importance of wheat research paper

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• Review Article
• Published: 13 August 2020

Strategies to improve wheat for human health

• Brittany Hazard   ORCID: orcid.org/0000-0002-3632-0415 1 ,
• Kay Trafford   ORCID: orcid.org/0000-0002-3814-0311 2 ,
• Alison Lovegrove 3 ,
• Simon Griffiths 4 ,
• Cristobal Uauy   ORCID: orcid.org/0000-0002-9814-1770 4 &
• Peter Shewry   ORCID: orcid.org/0000-0001-6205-2517 3  

Nature Food volume  1 ,  pages 475–480 ( 2020 ) Cite this article

1968 Accesses

62 Citations

50 Altmetric

Metrics details

• Biochemistry
• Biotechnology
• Gastroenterology

Despite their economic importance and growing demand, concerns are emerging around wheat-based foods and human health. Most wheat-based foods are made from refined white flour rather than wholemeal flour, and the overconsumption of these products may contribute to the increasing global prevalence of chronic diseases, particularly type 2 diabetes and obesity. Here, we review how the amount, composition and interactions of starch and cell wall polysaccharides, the major carbohydrate components in refined wheat products, impact human health. We discuss strategies and challenges to manipulate these components for improved diet and health using newly developed wheat genomics tools and resources. Commercial foods developed from these novel approaches must be produced without adverse effects on cost, consumer acceptability and processing properties.

This is a preview of subscription content, access via your institution

Access options

Access Nature and 54 other Nature Portfolio journals

Get Nature+, our best-value online-access subscription

24,99 € / 30 days

cancel any time

Subscribe to this journal

Receive 12 digital issues and online access to articles

111,21 € per year

only 9,27 € per issue

Buy this article

• Purchase on SpringerLink
• Instant access to full article PDF

Prices may be subject to local taxes which are calculated during checkout

Similar content being viewed by others

Sustainable plant-based ingredients as wheat flour substitutes in bread making

Historical changes in the contents and compositions of fibre components and polar metabolites in white wheat flour

Applying genomic resources to accelerate wheat biofortification

FAOSTAT Crops (Food and Agriculture Organization of the United Nations); http://www.fao.org/faostat/en/#data/QC

Mattei, J. et al. Reducing the global burden of type 2 diabetes by improving the quality of staple foods: the Global Nutrition and Epidemiologic Transition Initiative. Glob. Health 11 , 23 (2015).

Article   Google Scholar  

FAOSTAT New Food Balances (Food and Agriculture Organization of the United Nations); http://www.fao.org/faostat/en/#data/FBS

Shewry, P. R. & Hey, S. The contribution of wheat to human diet and health. Food Energy Secur. 4 , 178–202 (2015).

Article   PubMed   PubMed Central   Google Scholar  

Andersson, A. A. M. et al. Contents of dietary fibre components and their relation to associated bioactive components in whole grain wheat samples from the HEALTHGRAIN diversity screen. Food Chem. 136 , 1243–1248 (2013).

Article   CAS   PubMed   Google Scholar  

Brouns, F. J. P. H., van Buul, V. J. & Shewry, P. R. Does wheat make us fat and sick? J. Cereal Sci. 58 , 209–215 (2013).

Davis, W. R. Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health (Rodale Books, 2011).

EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA). Scientific opinion on the substantiation of health claims related to resistant starch and reduction of post-prandial glycaemic responses (ID 681), “digestive health benefits” (ID 682) and “favours a normal colon metabolism” (ID 783) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA J. 9 , 2024 (2011).

Article   CAS   Google Scholar  

Aune, D. et al. Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies. BMJ 353 , i2716 (2016).

Brownlee, I. A., Durukan, E., Masset, G., Hopkins, S. & Tee, E.-S. An overview of whole grain regulations, recommendations and research across Southeast Asia. Nutrients 10 , 752 (2018).

Article   PubMed Central   CAS   Google Scholar  

Seal, C. J. & Brownlee, I. A. Whole-grain foods and chronic disease: evidence from epidemiological and intervention studies. Proc. Nutr. Soc. 74 , 313–319 (2015).

Article   PubMed   Google Scholar  

Shao, Y. et al. Reduction of falling number in soft white spring wheat caused by an increased proportion of spherical B-type starch granules. Food Chem. 284 , 140–148 (2019).

Park, S.-H., Wilson, J. D. & Seabourn, B. W. Size granule distribution of hard red winter and hard red spring wheat: its effects on mixing and breadmaking quality. J. Cereal Sci. 49 , 98–105 (2009).

Chia, T. et al. A carbohydrate-binding protein, B-GRANULE CONTENT 1, influences starch granule size distribution in a dose-dependent manner in polyploid wheat. J. Exp. Bot. 71 , 105–115 (2020).

The definition of dietary fiber. Cereal Foods World 46 , 112–126 (2001); http://www.cerealsgrains.org/initiatives/definitions/Documents/DietaryFiber/DFDef.pdf

Haska, L., Nyman, M. & Andersson, R. Distribution and characterisation of fructan in wheat milling fractions. J. Cereal Sci. 48 , 768–774 (2008).

Loosveld, A.-M. A. et al. Structural variation and levels of water-extractable arabinogalactan-peptide in European wheat flours. Cereal Chem. 75 , 815–819 (1998).

Murphy, M. M., Douglass, J. S. & Birkett, A. Resistant starch intakes in the United States. J. Am. Diet. Assoc. 108 , 67–78 (2008).

Corrado, M. et al. Effect of semolina pudding prepared from starch branching enzyme IIa and b mutant wheat on glycaemic response in vitro and in vivo: a randomised controlled pilot study. Food Funct. 11 , 617–627 (2020).

Edwards, C. H. et al. Manipulation of starch bioaccessibility in wheat endosperm to regulate starch digestion, postprandial glycemia, insulinemia, and gut hormone responses: a randomized controlled trial in healthy ileostomy participants. Am. J. Clin. Nutr. 102 , 791–800 (2015).

Article   CAS   PubMed   PubMed Central   Google Scholar  

Ahuja, G., Jaiswal, S. & Chibbar, R. N. in Resistant Starch 1–22 (John Wiley and Sons, 2013).

Franco, C. M. L., do Rio Preto, S. J. & Ciacco, C. F. Factors that affect the enzymatic degradation of natural starch granules: effect of the size of the granules. Starch 11 , 422–426 (1992).

Bathgate, G. N., Clapperton, J. F. & Palmer, G. H. The significance of small starch granules. In Proc. Eur. Brew. Conv. Congr. Salzburg 183–186 (Elsevier, 1973).

Lovegrove, A. et al. Role of polysaccharides in food, digestion and health. Crit. Rev. Food Sci. Nutr. 57 , 237–253 (2015).

Aguilera, J. M. The food matrix: implications in processing, nutrition and health. Crit. Rev. Food Sci. Nutr. 59 , 3612–3629 (2019).

Chen, C. et al. Therapeutic effects of soluble fibre consumption on type 2 diabetes mellitus. Exp. Ther. Med. 12 , 1232–1242 (2016).

Article   ADS   CAS   PubMed   PubMed Central   Google Scholar  

Botticella, E. et al. Combining mutations at genes encoding key enzymes involved in starch synthesis affects the amylose content, carbohydrate allocation and hardness in the wheat grain. Plant Biotech. J. 16 , 1723–1734 (2018).

Gouseti, O. et al. Exploring the role of cereal dietary fibre in digestion. J. Agric. Food Chem. 67 , 8419–8424 (2019).

International Wheat Genetics Sequencing Consortium (IWGSC). Shifting the limits in wheat research and breeding using a fully annotated reference genome. Science 361 , eaar7191 (2018).

10+ Wheat Genomes Project The Wheat ‘Pan Genome’ (Wheat Initiative, 2011); http://www.10wheatgenomes.com/

Krasileva, K. V. et al. Uncovering hidden variation in polyploid wheat. Proc. Natl Acad. Sci. USA 114 , E913–E921 (2017).

Ramirez-Gonzalez, R. H., Uauy, C. & Caccamo, M. PolyMarker: a fast polyploid primer design pipeline. Bioinformatics 31 , 2038–2039 (2015).

Ramirez-Gonzalez, R. H. et al. The transcriptional landscape of polyploid wheat. Science 361 , eaar6089 (2018).

Article   PubMed   CAS   Google Scholar  

Borrill, P., Ramirez-Gonzalez, R. & Uauy, C. expVIP: a customizable RNA-seq data analysis and visualisation platform. Plant Physiol. 170 , 2172–2186 (2016).

Borrill, P., Harrington, S. A. & Uauy, C. Applying the latest advances in genomics and phenomics for trait discovery in polyploid wheat. Plant J. 97 , 56–72 (2019).

CAS   PubMed   Google Scholar  

Harrington, S. A., Backhaus, A. E., Singh, A., Hassani-Pak, K. & Uauy, C. The wheat GENIE3 network provides biologically-relevant information in polyploid wheat. G3 Genes Genomes Genetics https://doi.org/10.1534/g3.120.401436 (2020).

Arora, A. et al. Resistance gene cloning from a wild crop relative by sequence capture and association genetics. Nat. Biotechnol. 37 , 139–143 (2019).

Wingen, L. et al. Wheat landrace genome diversity. Genetics 205 , 1657–1676 (2017).

Zhang, Y. et al. Efficient and transgene-free genome editing in wheat through transient expression of CRISPR/Cas9 DNA or RNA. Nat. Commun. 7 , 12617 (2016).

Yamamori, M., Kato, M., Yui, M. & Kawasaki, M. Resistant starch and starch pasting properties of a starch synthase IIa-deficient wheat with apparent high amylose. Aust . J. Agric. Res. 57 , 531–535 (2006).

Hazard, B. et al. Mutations in durum wheat SBEII genes affect grain yield components, quality, and fermentation responses in rats. Crop Sci. 55 , 2813–2825 (2015).

Regina, A. et al. A genetic strategy generating wheat with very high amylose content. Plant Biotech. J. 13 , 1276–1286 (2015).

Schönhofen, A., Zhang, X. & Dubcovsky, J. Combined mutations in five wheat STARCH BRANCHING ENZYME II genes improve resistant starch but affect grain yield and bread-making quality. J. Cereal Sci. 75 , 165–174 (2017).

Borrill, P., Adamski, N. & Uauy, C. Genomics as the key to unlocking the polyploid potential of wheat. New Phytol. 208 , 1008–1022 (2015).

Chia, T. et al. Transfer of a starch phenotype from wild wheat to bread wheat by deletion of a locus controlling B-type starch granule content. J. Exp. Bot. 68 , 5497–5509 (2017).

Howard, T. et al. Identification of a major QTL controlling the content of B-type starch granules in Aegilops . J. Exp. Bot. 62 , 2217–2228 (2011).

Toole, G. A. et al. Spectroscopic analysis of diversity of arabinoxylan structures in cell walls of wheat cultivars ( Triticum aestivum ) in the HEALTHGRAIN diversity collection. J. Agric. Food Chem. 59 , 7075–7082 (2011).

Scheller, H. V. & Ulvskov, P. Hemicelluloses. Annu. Rev. of Plant Biol. 61 , 263–289 (2010).

Ward, J. et al. The HEALTHGRAIN cereal diversity screen: concept, results and prospects. J. Agric. Food Chem. 56 , 9699–9709 (2008).

Shewry, P. R. et al. Improving wheat as a source of dietary fibre for human health. Proc. Nutr. Soc. Summer Meeting 74 , E87 (Cambridge University Press, 2015).

Lovegrove, A. et al. Identification of a major QTL and associated marker for high arabinoxylan fibre in white wheat flour. PLoS ONE 15 , e0227826 (2020).

Lockyer, S. & Nugent, A. P. Health effects of resistant starch. Nutr. Bull. 42 , 10–41 (2017).

Mishra, A., Singh, A., Sharma, M., Kumar, P. & Roy, J. Development of EMS-induced mutation population for amylose and resistant starch variation in bread wheat ( Triticum aestivum ) and identification of candidate genes responsible for amylose variation. BMC Plant Biol. 16 , 217 (2016).

Article   PubMed   PubMed Central   CAS   Google Scholar  

Download references

Acknowledgements

Rothamsted Research, the John Innes Centre (JIC), NIAB and Quadram Institute Bioscience (QIB) receive grant-aided support from the Biotechnology and Biological Sciences Research Council (BBSRC) of the UK. The work at Rothamsted, the JIC and NIAB forms part of the Designing Future Wheat strategic programme (BB/P016855/1) and Molecules from Nature programme (BBS/E/J/000PR9799) and the work at QIB part of the Food Innovation and Health strategic programme (BB/R012512/1) and its constituent projects BBS/E/F/000PR10343 (Theme 1, Food Innovation) and BBS/E/F/000PR10345 (Theme 2, Digestion in the Upper GI Tract).

Author information

Authors and affiliations.

Quadram Institute Bioscience, Norwich, UK

Brittany Hazard

NIAB, Cambridge, UK

Kay Trafford

Rothamsted Research, Hertfordshire, UK

Alison Lovegrove & Peter Shewry

John Innes Centre, Norwich, UK

Simon Griffiths & Cristobal Uauy

You can also search for this author in PubMed   Google Scholar

Contributions

All authors contributed to writing the article.

Corresponding author

Correspondence to Peter Shewry .

Ethics declarations

Competing interests.

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Cite this article.

Hazard, B., Trafford, K., Lovegrove, A. et al. Strategies to improve wheat for human health. Nat Food 1 , 475–480 (2020). https://doi.org/10.1038/s43016-020-0134-6

Download citation

Received : 06 December 2019

Accepted : 17 July 2020

Published : 13 August 2020

Issue Date : August 2020

DOI : https://doi.org/10.1038/s43016-020-0134-6

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

This article is cited by

A multi-omic resource of wheat seed tissues for nutrient deposition and improvement for human health.

• Jingjing Zhi

Scientific Data (2023)

Combatting Fusarium head blight: advances in molecular interactions between Fusarium graminearum and wheat

Phytopathology Research (2022)

Loss of starch synthase IIIa changes starch molecular structure and granule morphology in grains of hexaploid bread wheat

• Brendan Fahy
• Oscar Gonzalez
• Brittany A. Hazard

Scientific Reports (2022)

A stealth health approach to dietary fibre

• P. Stephen Baenziger
• Katherine Frels
• Rod Wallace

Nature Food (2022)

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Sign up for the Nature Briefing: Translational Research newsletter — top stories in biotechnology, drug discovery and pharma.

Information

• Author Services

Initiatives

You are accessing a machine-readable page. In order to be human-readable, please install an RSS reader.

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited. For more information, please refer to https://www.mdpi.com/openaccess .

Feature papers represent the most advanced research with significant potential for high impact in the field. A Feature Paper should be a substantial original Article that involves several techniques or approaches, provides an outlook for future research directions and describes possible research applications.

Feature papers are submitted upon individual invitation or recommendation by the scientific editors and must receive positive feedback from the reviewers.

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

Original Submission Date Received: .

• Active Journals
• Find a Journal
• Proceedings Series
• For Authors
• For Reviewers
• For Editors
• For Librarians
• For Publishers
• For Societies
• For Conference Organizers
• Open Access Policy
• Institutional Open Access Program
• Special Issues Guidelines
• Editorial Process
• Research and Publication Ethics
• Article Processing Charges
• Testimonials
• Preprints.org
• SciProfiles
• Encyclopedia

Article Menu

• Subscribe SciFeed
• Recommended Articles
• Google Scholar
• on Google Scholar
• Table of Contents

Find support for a specific problem in the support section of our website.

Please let us know what you think of our products and services.

Visit our dedicated information section to learn more about MDPI.

JSmol Viewer

Meeting the challenges facing wheat production: the strategic research agenda of the global wheat initiative.

1. Introduction

2. background, 2.1. why wheat, 2.2. impact of climate change, 2.3. the wheat initiative, 2.4. global wheat research, 3. existing strategic research agenda—work in progress.

3.1. Objective 1: To Increase Yield Potential

3.2. objective 2: to protect ‘on farm’ yield, 3.3. objective 3: ensuring the supply of high-quality safe wheat, 3.4. objective 4: enabling technologies and the sharing of resources, 3.5. objective 5: germplasm accessibility, 3.6. objective 6: knowledge exchange, education and training, 4. major issues and challenges facing wheat production and research, 4.1. inconsistencies in regulatory environment, 4.2. access to staff with the necessary skills in both new and old technologies, 4.3. data access and standards, 4.4. support for multinational research and public–private partnerships, 5. research priorities, 5.1. strengthen existing research activities, 5.2. enhance agronomy in its broadest definition (crop production and soil management), 5.3. increase genetic diversity.

• A broad series of activities can be undertaken to address this research priority:
• Revise and update the Global Wheat Conservation Strategy prepared in 2007 [ 26 ].
• Encourage the large-scale genotyping and phenotypic characterisation of germplasm held in the major genebanks.
• Advocate for the free and open exchange of germplasm and associated data.
• Encourage the utilisation of existing specialist germplasm collections collated by EWGs and share the outcomes: ◦ Tetraploid collections developed by the Durum EWG ▪ Durum elite and landrace collection in conjunction with a tetraploid core collection (GDP: Global Durum wheat Panel) capturing about 80% of the AABB haplotypes [ 27 ] of the collection (TGC: Tetraploid wheat Global Collection) described in [ 28 ]. ◦ Heat and drought tolerant germplasm collections developed by HeDWIC. ◦ Wheat quality assessment panels developed by the Quality EWG.
• Support research aimed at the enhanced utilisation of unadapted germplasm: ◦ Development of introgression populations. ◦ Re-domestication. ◦ Exploration of novel germplasm evaluation strategies. ◦ Development of efficient methods for gene editing.

5.4. Understanding Root and Soil Biology

• Continuing improvement of root phenotyping techniques, particularly in the field.
• Expand information of soil–microbe–plant interactions.
• Integration of data and information on roots and the microbiome in the analysis of wheat production with the full cropping system. It will also be important to emphasise the differences between low and high input systems and organic farming.

6. Wheat Initiative Structure and Organisation

6.1. develop educational and training programs.

• Ensure the full and rapid implementation of the postgraduate and ECR plan for involvement in the EWGs.
• Establish an exchange program that provides partial funding for students to work in other laboratories.
• Encourage EWGs to deliver training workshops and courses, and link to existing options offered by other organisations, such as universities, CIMMYT and ICARDA.
• Develop an online Wheat Initiative seminar program.
• Develop mentoring programs to support students and link to industry.

6.2. The Wheat Initiative as an Advocacy and Lobby Organisation

• Produce public explanatory documents and videos covering the Wheat Initiative activities, major topics and issues affecting wheat production, such as the role of germplasm exchange, gene editing, hybrid wheat, and crop protection.
• Participate in relevant G20 workshops and meetings and develop links to government agencies and international organisations.
• Advocate and lobby for the support of transnational research.
• Develop links to the wheat grower and processing industry organisations.
• Promote wheat resources such as WheatIS and WheatVIVO.

6.3. Expand Engagement

• The Institutions’ Coordination Committee has established a sub-committee to work through the options to build membership.
• Develop and distribute documentation explaining the value to industry from joining the WI—Industry.
• Increase industry participation in WI activities, particularly in training and mentorship: a component would be to identify platforms and capabilities that could be used by industry.
• Identify and target government and institutional organisations in major wheat producing and wheat-importing countries to seek greater engagement in the WI.
• Target early career researchers in under-represented countries to encourage the membership of EWGs. In addition, provide support to allow key people from these regions to participate in WI activities.

6.4. Supporting Multinational Research

• Stage 1 —Coordination across existing research to capture synergies, prevent duplication and identify gaps—low incremental costs but a proactive coordination is instrumental and essential.
• Stage 2 —Project alignment and leverage of existing investments: initially focus on the twinning of existing projects or building on a call(s) for proposals by one or more national funders joining (e.g., recent AAFC (Canada)/BBSRC (UK) IWYP-aligned call-linked consecutive calls for proposals in each country).
• Stage 3 —Scaling-up joint investment: under the key areas of interest to all funders, funding can be allocated to a common/centrally managed pot/program or managed nationally by a lead funder, still aligned under a broad umbrella theme.

7. Conclusions

• Boost research and technology delivery capabilities by investing in staff and student training and encourage and support the exchange of personnel between research organisations and building research infrastructure. This can be achieved if national research programmes place priority on activities with strong international linkages. Financial or organisational support from national agencies to research groups seeking participation in international partnerships would be beneficial.
• Provide support, both financial and organisational, to international activities aiming to facilitate the exchange of resources, particularly germplasm, and support the evaluation and delivery of research outcomes.
• Actively participate in Wheat Initiative research alliances that gather the capabilities and resources targeting global research challenges. These include the work of the Expert Working Groups and the three current alliances: The International Wheat Yield Partnership (boosting wheat yield potential), the Alliance for Wheat Adaptation to Heat and Drought (producing heat- and drought-tolerant germplasm) and the Wheat Initiative Crop Health Alliance (diagnosis and monitoring of wheat diseases).

Author Contributions

Data availability statement, acknowledgments, conflicts of interest, abbreviations.

• FAO. Land Use in Agriculture by the Numbers. 2022. Available online: https://www.fao.org/sustainability/news/detail/en/c/1274219/#:~:text=Global%20trends,and%20pastures)%20for%20grazing%20livestock (accessed on 19 September 2022).
• World Bank. Arable Land (Hectares per Person). 2022. Available online: https://data.worldbank.org/indicator/AG.LND.ARBL.HA.PC (accessed on 19 September 2022).
• FAOSTAT. 2022. Available online: https://www.fao.org/faostat/en/#data (accessed on 19 September 2022).
• Braun, H.J.; Atlin, G.; Payne, T. Multi-location testing as a tool to identify plant response to global climate change. In Climate Change & Crop Production ; Reynolds, M.P., Ed.; CABI: Oxfordshire, UK, 2010; pp. 115–138. [ Google Scholar ] [ CrossRef ]
• Cossani, C.M.; Reynolds, M.P. Physiological traits for improving heat tolerance in wheat. Plant Physiol. 2012 , 160 , 1710–1718. [ Google Scholar ] [ CrossRef ] [ PubMed ] [ Green Version ]
• Moore, C.E.; Meacham-Hensold, K.; Lemonnier, P.; Slattery, R.A.; Benjamin, C.; Bernacchi, C.J.; Cavanagh, A.P. The effect of increasing temperature on crop photosynthesis: From enzymes to ecosystems. J. Exp. Biol. 2021 , 72 , 2822–2844. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Sarhadi, A.; Ausín, M.C.; Wiper, M.P.; Touma, D.; Diffenbaugh, N.S. Multidimensional risk in a nonstationary climate: Joint probability of increasingly severe warm and dry conditions. Sci. Adv. 2018 , 4 , eaau3487. [ Google Scholar ] [ CrossRef ] [ PubMed ] [ Green Version ]
• Gaupp, F.; Hall, J.; Hochrainer-Stigler, S.; Dadson, S. Changing risks of simultaneous global breadbasket failure. Nat. Clim. Chang. 2020 , 10 , 54–57. [ Google Scholar ] [ CrossRef ]
• Kornhuber, K.; Coumou, D.; Vogel, E.; Lesk, C.; Donges, J.F.; Lehmann, J.; Horton, R.M. Amplified Rossby waves enhance risk of concurrent heatwaves in major breadbasket regions. Nat. Clim. Chang. 2020 , 10 , 48–53. [ Google Scholar ] [ CrossRef ]
• Zampieri, M.; Ceglar, A.; Dentener, F.; Toreti, A. Wheat yield loss attributable to heat waves, drought and water excess at the global, national and subnational scales. Environ. Res. Lett. 2017 , 12 , 064008. [ Google Scholar ] [ CrossRef ]
• Trnka, M.; Feng, S.; Semenov, M.A.; Olesen, J.E.; Kersebaum, K.C.; Rötter, R.P.; Semerádová, D.; Klem, K.; Huang, W.; Ruiz-Ramos, M.; et al. Mitigation efforts will not fully alleviate the increase in water scarcity occurrence probability in wheat-producing areas. Sci. Adv. 2019 , 5 , eaau2406. [ Google Scholar ] [ CrossRef ] [ Green Version ]
• Liu, B.; Asseng, S.; Müller, C.; Ewert, F.; Elliott, J.; Lobell, D.B.; Martre, P.; Ruane, A.C.; Wallach, D.; Jones, J.W.; et al. Similar estimates of temperature impacts on global wheat yield by three independent methods. Nat. Clim. Chang. 2016 , 6 , 1130–1136. [ Google Scholar ] [ CrossRef ]
• Zaoh, C.; Liu, B.; Piao, S.; Wang, X.; Lobell, D.B.; Huang, Y.; Huang, M.; Yao, Y.; Bassu, S.; Ciais, P.; et al. Temperature increase reduces global yields of major crops in four independent estimates. Proc. Natl. Acad. Sci. USA 2017 , 114 , 9326–9331. [ Google Scholar ] [ CrossRef ]
• Challinor, A.J.; Watson, J.; Lobell, D.B.; Howden, S.M.; Smith, D.R.; Chhetri, N. A meta-analysis of crop yield under climate change and adaptation. Nat. Clim. Chang. 2014 , 4 , 287–291. [ Google Scholar ] [ CrossRef ] [ Green Version ]
• Ainsworth, E.A.; Long, S.P. 30 years of free-air carbon dioxide enrichment (FACE): What have we learned about future crop productivity and its potential for adaptation? Glob. Chang. Biol. 2020 , 27 , 27–49. [ Google Scholar ] [ CrossRef ]
• Russell, K.; Van Sanford, D.A. Breeding wheat for resilience to increasing nighttime temperatures. Agronomy 2020 , 10 , 531. [ Google Scholar ] [ CrossRef ] [ Green Version ]
• Beres, B.L.; Hatfield, J.L.; Kirkegaard, J.A.; Eigenbrode, S.D.; Pan, W.L.; Lollato, R.P.; Hunt, J.R.; Strydhorst, S.; Porker, K.; Lyon, D.; et al. Towards a better understanding of genotype × environment × management interactions—A global wheat initiative agronomic research strategy. Front. Plant Sci. 2020 , 11 , 828. [ Google Scholar ] [ CrossRef ]
• Pardey, P.G.; Chan-Kang, C.; Dehmer, S.P.; Beddow, J.M. Agriculture R&D is on the move. Nature 2016 , 537 , 301–303. [ Google Scholar ] [ CrossRef ] [ Green Version ]
• Pardey, P.G.; Chan-Kang, C.; Beddow, J.M.; Dehmer, S.P. Long-run and Global R&D Funding Trajectories: The US Farm Bill in a Changing Context. Am. J. Agric. Econ. 2015 , 97 , 1312–1323. [ Google Scholar ] [ CrossRef ]
• Walkowiak, S.; Gao, L.; Monat, C.; Haberer, G.; Kassa, M.T.; Brinton, J.; Ramirez-Gonzalez, R.H.; Kolodziej, M.C.; Delorean, E.; Thambugala, D.; et al. Multiple wheat genomes reveal global variation in modern breeding. Nature 2020 , 588 , 277–283. [ Google Scholar ] [ CrossRef ]
• McCouch, S.; Baute, G.J.; Bradeen, J.; Bramel, P.; Bretting, P.K.; Buckler, E.; Burke, J.M.; Charest, D.; Cloutier, S.; Cole, G.; et al. Agriculture: Feeding the future. Nature 2013 , 499 , 23–24. [ Google Scholar ] [ CrossRef ] [ Green Version ]
• Feuillet, C.; Langridge, P.; Waugh, R. Cereal breeding takes a walk on the wild side. Trends Genet. 2008 , 24 , 24–32. [ Google Scholar ] [ CrossRef ]
• Dreisigacker, S.; Kishee, M.; Lahe, J.; Warburton, M. Use of synthetic hexaploid wheat to increase diversity for CIMMYT bread wheat improvement. Aust. J. Agric. Res. 2008 , 59 , 413–420. [ Google Scholar ] [ CrossRef ]
• Miller, T.E. Systematics and evolution. In Wheat Breeding: Its Scientific Basis ; Lupton, F.G.H., Ed.; Chapman & Hall: London, UK, 1987; pp. 1–30. [ Google Scholar ]
• Hatta, M.A.M.; Steuernagel, B.; Wulff, B.B.H. Rapid gene cloning in wheat. In Applications of Genetics and Genomic Research in Cereals ; Miedaner, T., Korzun, V., Eds.; Woodhead Publishing: Swaston, UK, 2019; pp. 65–95. [ Google Scholar ] [ CrossRef ]
• CIMMYT. Global Strategy for the Ex Situ Conservation with Enhanced Access to Wheat, Rye and Triticale Genetic Resources. 2007. Available online: https://www.croptrust.org/fileadmin/uploads/croptrust/Documents/Ex_Situ_Crop_Conservation_Strategies/Wheat-Strategy-FINAL-20Sep07.pdf (accessed on 19 September 2022).
• Mazzucotelli, E.; Sciara, G.; Mastrangelo, A.M.; Desiderio, F.; Xu, S.S.; Faris, J.; Hayden, M.J.; Tricker, P.J.; Ozkan, H.; Echenique, V.; et al. The Global Durum Wheat Panel (GDP): An International Platform to Identify and Exchange Beneficial Alleles. Front. Plant Sci. 2020 , 11 , 569905. [ Google Scholar ] [ CrossRef ]
• Maccaferri, M.; Harris, N.S.; Twardziok, S.O.; Pasam, R.K.; Gundlach, H.; Spannagl, M.; Ormanbekova, D.; Lux, T.; Prade, V.M.; Milner, S.G.; et al. Durum wheat genome highlights past domestication signatures and future improvement targets. Nat. Gen. 2019 , 51 , 885–895. [ Google Scholar ] [ CrossRef ] [ PubMed ] [ Green Version ]
• Ober, E.S.; Alahmad, S.; Cockram, J.; Forestan, C.; Hickey, L.T.; Kant, J.; Maccaferri, M.; Marr, E.; Milner, M.; Pinto, F.; et al. Wheat root systems as a breeding target for climate resilience. Theor. Appl. Genet. 2021 , 134 , 1645–1662. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Maccaferri, M.; El-Feki, W.; Nazemi, G.; Salvi, S.; Canè, M.A.; Cholalongo, M.C.; Stefanelli, S.; Tuberosa, R. Prioritizing quantitative trait loci for root system architecture in tetraploid wheat. J. Exp. Bot. 2016 , 67 , 1161–1178. [ Google Scholar ] [ CrossRef ] [ PubMed ]
• Alahmad, S.; El Hassouni, K.; Bassi, F.M.; Dinglasan, E.; Youssef, C.; Quarry, G.; Aksoy, A.; Mazzucotelli, E.; Juhász, A.; Able, J.A.; et al. A major root architecture QTL responding to water limitation in durum wheat. Front. Plant Sci. 2019 , 10 , 436. [ Google Scholar ] [ CrossRef ] [ PubMed ]

Click here to enlarge figure

Share and Cite

Langridge, P.; Alaux, M.; Almeida, N.F.; Ammar, K.; Baum, M.; Bekkaoui, F.; Bentley, A.R.; Beres, B.L.; Berger, B.; Braun, H.-J.; et al. Meeting the Challenges Facing Wheat Production: The Strategic Research Agenda of the Global Wheat Initiative. Agronomy 2022 , 12 , 2767. https://doi.org/10.3390/agronomy12112767

Langridge P, Alaux M, Almeida NF, Ammar K, Baum M, Bekkaoui F, Bentley AR, Beres BL, Berger B, Braun H-J, et al. Meeting the Challenges Facing Wheat Production: The Strategic Research Agenda of the Global Wheat Initiative. Agronomy . 2022; 12(11):2767. https://doi.org/10.3390/agronomy12112767

Langridge, Peter, Michael Alaux, Nuno Felipe Almeida, Karim Ammar, Michael Baum, Faouzi Bekkaoui, Alison R. Bentley, Brian L. Beres, Bettina Berger, Hans-Joachim Braun, and et al. 2022. "Meeting the Challenges Facing Wheat Production: The Strategic Research Agenda of the Global Wheat Initiative" Agronomy 12, no. 11: 2767. https://doi.org/10.3390/agronomy12112767

Article Metrics

Article access statistics, further information, mdpi initiatives, follow mdpi.

Subscribe to receive issue release notifications and newsletters from MDPI journals

• Search Menu
• Sign in through your institution
• Advance articles
• Darwin Reviews
• Special Issues
• Expert View
• Flowering Newsletter Reviews
• Technical Innovations
• Editor's Choice
• Virtual Issues
• Community Resources
• Reasons to submit
• Author Guidelines
• Peer Reviewers
• Submission Site
• Open Access
• About Journal of Experimental Botany
• About the Society for Experimental Biology
• Editorial Board
• Advertising and Corporate Services
• Journals Career Network
• Permissions
• Self-Archiving Policy
• Dispatch Dates
• Journal metrics
• Journals on Oxford Academic
• Books on Oxford Academic

Article Contents

Introduction, origin and evolution of wheat, cultivated wheats today, why has wheat been so successful, wheat gluten proteins and processing properties, wheat in nutrition and health, adverse reactions to wheat, the future for wheat.

• < Previous
• Article contents
• Figures & tables
• Supplementary Data

P. R. Shewry, Wheat, Journal of Experimental Botany , Volume 60, Issue 6, April 2009, Pages 1537–1553, https://doi.org/10.1093/jxb/erp058

• Permissions Icon Permissions

Wheat is the dominant crop in temperate countries being used for human food and livestock feed. Its success depends partly on its adaptability and high yield potential but also on the gluten protein fraction which confers the viscoelastic properties that allow dough to be processed into bread, pasta, noodles, and other food products. Wheat also contributes essential amino acids, minerals, and vitamins, and beneficial phytochemicals and dietary fibre components to the human diet, and these are particularly enriched in whole-grain products. However, wheat products are also known or suggested to be responsible for a number of adverse reactions in humans, including intolerances (notably coeliac disease) and allergies (respiratory and food). Current and future concerns include sustaining wheat production and quality with reduced inputs of agrochemicals and developing lines with enhanced quality for specific end-uses, notably for biofuels and human nutrition.

Wheat is counted among the ‘big three’ cereal crops, with over 600 million tonnes being harvested annually. For example, in 2007, the total world harvest was about 607 m tonnes compared with 652 m tonnes of rice and 785 m tonnes of maize ( http://faostat.fao.org/ ). However, wheat is unrivalled in its range of cultivation, from 67º N in Scandinavia and Russia to 45º S in Argentina, including elevated regions in the tropics and sub-tropics ( Feldman, 1995 ). It is also unrivalled in its range of diversity and the extent to which it has become embedded in the culture and even the religion of diverse societies.

Most readers will be aware of the significance of bread in the Judaeo-Christian tradition including the use of matzo (hard flat bread) at the Jewish Passover and of bread to represent the ‘host’ at the Christian Eucharist (Holy Communion). The latter may be a thin unleavened wafer, similar to the Jewish matzo, in the Roman Catholic Church and some Protestant denominations, or leavened in other Protestant denominations and the Eastern Orthodox Church. But how many readers are aware that bread is treated as sacred in everyday life in the largely Muslim communities of Central Asia, such as Uzbekistan and Kyrgyzstan? In this culture, the leavened round breads (nan) are stamped before baking and must be treated with respect, including being kept upright and never left on the ground or thrown away in public. These customs almost certainly originate from earlier indigenous religions in the Middle East in which wheat played a similar role and was sometimes equated with the sun and its god.

Although such cultural and religious traditions are fascinating and will certainly reward further study, they are essentially outside the scope of this article which will examine why wheat has developed and continues to be so successful as a crop and food source.

The first cultivation of wheat occurred about 10 000 years ago, as part of the ‘Neolithic Revolution’, which saw a transition from hunting and gathering of food to settled agriculture. These earliest cultivated forms were diploid (genome AA) (einkorn) and tetraploid (genome AABB) (emmer) wheats and their genetic relationships indicate that they originated from the south-eastern part of Turkey ( Heun et al. , 1997 ; Nesbitt, 1998 ; Dubcovsky and Dvorak, 2007 ). Cultivation spread to the Near East by about 9000 years ago when hexaploid bread wheat made its first appearance ( Feldman, 2001 ).

The earliest cultivated forms of wheat were essentially landraces selected by farmers from wild populations, presumably because of their superior yield and other characteristics, an early and clearly non-scientific form of plant breeding! However, domestication was also associated with the selection of genetic traits that separated them from their wild relatives. This domestication syndrome has been discussed in detail by others, but two traits are of sufficient importance to mention here. The first is the loss of shattering of the spike at maturity, which results in seed loss at harvesting. This is clearly an important trait for ensuring seed dispersal in natural populations and the non-shattering trait is determined by mutations at the Br ( brittle rachis ) locus ( Nalam et al. , 2006 ).

The second important trait is the change from hulled forms, in which the glumes adhere tightly to the grain, to free-threshing naked forms. The free forms arose by a dominant mutant at the Q locus which modified the effects of recessive mutations at the Tg ( tenacious glume ) locus ( Jantasuriyarat et al. , 2004 ; Simons et al. , 2006 ; Dubkovsky and Dvorak, 2007 ).

Cultivated forms of diploid, tetraploid, and hexaploid wheat all have a tough rachis apart from the spelt form of bread wheat. Similarly, the early domesticated forms of einkorn, emmer, and spelt are all hulled, whereas modern forms of tetraploid and hexaploid wheat are free-threshing.

Whereas einkorn and emmer clearly developed from the domestication of natural populations, bread wheat has only existed in cultivation, having arisen by hybridization of cultivated emmer with the unrelated wild grass Triticum tauschii (also called Aegilops tauschii and Ae . squarosa ). This hybridization probably occurred several times independently with the novel hexaploid (genome AABBDD) being selected by farmers for its superior properties. The evolution of modern wheats is illustrated in Fig. 1 which also shows examples of spikes and grain.

The evolutionary and genome relationships between cultivated bread and durum wheats and related wild diploid grasses, showing examples of spikes and grain. Modified from Snape and Pánková (2006) , and reproduced by kind permission of Wiley-Blackwell.

The genetic changes during domestication mean that modern wheats are unable to survive wild in competition with better adapted species. This was elegantly demonstrated by John Bennet Lawes in the 1880s when he decided to allow part of the famous long-term Broadbalk experiment at Rothamsted to return to its natural state ( Dyke, 1993 ). He therefore left part of the wheat crop unharvested in 1882 and monitored the growth in successive years. After a good crop in 1883 the weeds dominated and in 1885 the few remaining wheat plants (which were spindly with small ears) were collected and photographed.

The A genomes of tetraploid and hexaploid wheats are clearly related to the A genomes of wild and cultivated einkorn, while the D genome of hexaploid wheat is clearly derived from that of T . tauschii . In fact, the formation of hexaploid wheat occurred so recently that little divergence has occurred between the D genomes present in the hexaploid and diploid species. By contrast, the B genome of tetraploid and hexaploid wheats is probably derived from the S genome present in the Sitopsis section of Aegilops , with Ae . speltoides being the closest extant species. The S genome of Ae . speltoides is also closest to the G genome of T . timopheevi , a tetraploid species with the A and G genomes ( Feldman, 2001 ).

The spread of wheat from its site of origin across the world has been elegantly described by Feldman (2001) and is only summarized here. The main route into Europe was via Anatolia to Greece (8000 BP) and then both northwards through the Balkans to the Danube (7000 BP) and across to Italy, France and Spain (7000 BP), finally reaching the UK and Scandanavia by about 5000 BP. Similarly, wheat spread via Iran into central Asia reaching China by about 3000 BP and to Africa, initially via Egypt. It was introduced by the Spaniards to Mexico in 1529 and to Australia in 1788.

Currently, about 95% of the wheat grown worldwide is hexaploid bread wheat, with most of the remaining 5% being tetraploid durum wheat. The latter is more adapted to the dry Mediterranean climate than bread wheat and is often called pasta wheat to reflect its major end-use. However, it may also be used to bake bread and is used to make regional foods such as couscous and bulgar in North Africa. Small amounts of other wheat species (einkorn, emmer, spelt) are still grown in some regions including Spain, Turkey, the Balkans, and the Indian subcontinent. In Italy, these hulled wheats are together called faro ( Szabó and Hammer, 1996 ) while spelt continues to be grown in Europe, particularly in Alpine areas ( Fossati and Ingold, 2001 ).

The recent interest in spelt and other ancient wheats (including kamut, a tetraploid wheat of uncertain taxonomy, related to durum wheat) as healthy alternatives to bread wheat ( Abdel-Aal et al. , 1998 ) may also lead to wider growth for high value niche markets in the future.

Despite its relatively recent origin, bread wheat shows sufficient genetic diversity to allow the development of over 25 000 types ( Feldman et al. , 1995 ) which are adapted to a wide range of temperate environments. Provided sufficient water and mineral nutrients are available and effective control of pests and pathogens is ensured, yields can exceed 10 tonnes ha −1 , comparing well with other temperate crops. However, deficiencies in water and nutrients and the effects of pests and pathogens cause the global average yield to be low, at about 2.8 tonnes ha −1 . Wheat is also readily harvested using mechanical combine harvesters or traditional methods and can be stored effectively indefinitely before consumption, provided the water content is below about 15% dry weight and pests are controlled.

There is no doubt that the adaptability and high yields of wheat have contributed to its success, but these alone are not sufficient to account for its current dominance over much of the temperate world. The key characteristic which has given it an advantage over other temperate crops is the unique properties of doughs formed from wheat flours, which allow it to be processed into a range of breads and other baked products (including cakes and biscuits), pasta and noodles, and other processed foods. These properties depend on the structures and interactions of the grain storage proteins, which together form the ‘gluten’ protein fraction.

Transcriptomic studies have shown that over 30 000 genes are expressed in the developing wheat grain ( Wan et al. , 2008 ) while proteomic analysis of mature grain has revealed the presence of about 1125 individual components ( Skylas et al. , 2000 ). However, many of these components are present in small amounts and have little or no impact on the utilization of the grain, with one protein fraction being dominant in terms of amount and impact. This fraction is the prolamin storage proteins, which correspond to the gluten proteins. The precise number of individual gluten protein components has not been determined, but 2D gel analyses suggest that about 100 is a reasonable estimate. Together they have been estimated to account for about 80% of the total grain protein in European wheats ( Seilmeier et al. , 1991 ).

Gluten was one of the earliest protein fractions to be described by chemists, being first described by Beccari in 1728 (see translation by Bailey, 1941 ). It is traditionally prepared by gently washing wheat dough in water or dilute salt solution, leaving a cohesive mass which comprises about 80% protein, the remainder being mainly starch granules which are trapped in the protein matrix.

The ability to prepare the gluten proteins in an essentially pure state by such a simple procedure depends on their unusual properties. Firstly, they are insoluble in water or dilute salt solutions but are soluble in alcohol/water mixtures (as discussed below) and were hence defined as ‘prolamins’ by TB Osborne in his classic studies of plant proteins carried out at the end of the 19th century and the start of the 20th century ( Osborne, 1924 ). Secondly, the individual gluten proteins are associated by strong covalent and non-covalent forces which allow the whole fraction to be isolated as a cohesive mass.

What is the origin of gluten?

In common with other seed storage proteins, the gluten proteins are secretory proteins, being synthesized on the rough endoplasmic reticulum and co-translationally transported into the lumen of the ER. Once within the ER lumen, cereal seed storage proteins may follow two routes: a Golgi-dependent route leading to deposition within protein bodies of vacuolar origin or a Golgi-independent route in which protein deposits formed within the ER lumen may ultimately fuse with protein bodies of vacuolar origin (see Kumamaru et al. , 2007 , for a review).

Work carried out by Galili and colleagues ( Levanany et al. , 1992 ; Galili et al. , 1995 ; Galili, 1997 ) indicated that wheat gluten proteins may follow both routes, and this has recently been confirmed using epitope tags and specific antibodies to follow individual proteins and groups of proteins in cells of developing grain ( Tosi et al. , 2009 ). It is also clear that the protein deposits fuse to form a continuous matrix as the cells of the starchy endosperm dry and die during the later stages of grain maturation ( Fig. 2A ). Thus a proteinaceous network is present in each endosperm cell ( Fig. 2B ) and these networks are brought together when flour is mixed with water to form a continuous network in the dough. Washing the dough to remove non-gluten components therefore allows the network to be recovered as the cohesive mass which is called gluten ( Fig. 2C ).

The origin of wheat gluten. (A) Transmission electron microscopy of the developing starchy endosperm cells at 46 d after anthesis shows that the individual protein bodies have fused to form a continuous proteinaceous matrix. Taken from Shewry et al. , 1995 , ( Biotechnology 13, 1185–1190) and provided by Dr M Parker (IFR, Norwich, UK). (B) Digestion of a flour particle with amylases to remove starch reveals a continuous proteinaceous network. Taken from Amend and Beauvais (1995) and reproduced by kind permission of Getreidetechnologie. (C) After kneading, dough can be washed to recover the gluten network as a cohesive mass which is stretched in the photograph to demonstrate its viscoelastic properties.

The biochemical and molecular basis for gluten functionality

Humankind has been aware for many centuries that wheat dough has unusual properties which are shared to a limited extent by doughs made from rye flour but not by those from other cereal flours. These properties, which are usually described as ‘viscoelasticity’, are particularly important in making leavened bread, as they allow the entrapment of carbon dioxide released during leavening. However, they also underpin a range of other uses including making unleavened breads, cakes, and biscuits, pasta (from durum wheat), and noodles (from bread wheat). They are also exploited in the food industry where gluten proteins may be used as a binder in processed foods.

The volume of research carried out on wheat gluten is vast, with a simple search of the Web of Science database showing almost 20 000 papers since 1945. This volume not only reflects the commercial importance of wheat processing, but also the complexity of the system which remains incompletely understood. They include studies at the genetic, biochemical, biophysical, and functional (ie processing) levels.

Genetic studies have exploited the extensive polymorphism which exists between the gluten protein fractions present in different genotypes to establish genetic linkages between either groups of gluten proteins, or allelic forms of these, and aspects of processing quality. Similarly, studies at the biochemical and biophysical levels have demonstrated a relationship between dough strength and the ability of the gluten proteins to form polymeric complexes (called glutenins). Combining results from these two approaches highlighted the importance of a specific group of gluten proteins, called the high molecular weight (HMW) subunits of glutenin.

Cultivars of bread wheat express between three and five HMW subunit genes, with the encoded proteins accounting for up to about 12% of the total grain protein ( Seilmeier et al. , 1991 ; Halford et al. , 1992 ). The HMW subunits are only present in high molecular mass polymers and allelic variation in both the number of expressed genes and the properties of the encoded proteins results in effects on the amount and size of the polymers and hence dough strength (reviewed by Payne, 1987 ; Shewry et al. , 2003 b ). These glutenin polymers are known to be stabilized by inter-chain disulphide bonds, but it is apparent that non-covalent hydrogen bonds are also important in stabilizing the interactions between glutenin polymers and monomeric gluten proteins (called gliadins) ( Belton, 2005 ). Hence, the individual gliadins and glutenin polymers can be separated using solvents which disrupt hydrogen bonding (such as urea) but reducing agents (such as 2-mercaptoethanol or dithiothreitol) are required to break down the glutenin polymers to release the individual subunits.

Although the HMW subunits are the main determinants of glutenin elasticity relationships between other gluten proteins and functional properties have also been reported (reviewed by Shewry et al. , 2003 a ).

The relationship between the HMW subunits and dough strength was first established over 25 years ago ( Payne et al. , 1979 ) and allelic forms associated with good processing quality have been selected by plant breeders for over two decades, using simple SDS-PAGE separations. The established relationships between the number of expressed HMW subunit genes, the total amount of HMW subunit protein and dough strength have also resulted in the HMW subunit genes being an attractive target for genetic transformation, in order to increase their gene copy number and hence dough strength.

The first studies of this type were reported over 10 years ago ( Altpeter et al. , 1996 ; Blechl and Anderson, 1996 ; Barro et al. , 1997 ) and many studies have since been reported (reviewed by Shewry and Jones, 2005 ; Jones et al. , 2009 ). It is perhaps not surprizing that the results have been ‘mixed’, but some conclusions can be drawn. Firstly, expression of an additional HMW subunit gene can lead to increased dough strength, even when a modern good quality wheat cultivar is used as the recipient (see Field et al. , 2008 ; Rakszegi et al. , 2008 , as recent examples, and reviews of earlier work cited above). However, the effect depends on the precise HMW subunit gene which is used and on the expression level, with the transgenes resulting in over-strong (ie too elastic) gluten properties in some studies. Thus, although transgenesis is a realistic strategy to increase dough strength in wheat, it is also necessary to have an understanding of the underlying mechanisms in order to optimize the experimental design.

Wheat is widely consumed by humans, in the countries of primary production (which number over 100 in the FAO production statistics for 2004) and in other countries where wheat cannot be grown. For example, imported wheat is used to meet consumer demands for bread and other food products in the humid tropics, particularly those with a culinary tradition dating back to colonial occupation. Statistics are not available for the total volume of wheat which is consumed directly by humans as opposed to feeding livestock, although figures for the UK indicate about one-third of the total production (approximately 5.7 m tonnes per annum are milled with home production being 15–16 m tonnes). Globally there is no doubt that the number of people who rely on wheat for a substantial part of their diet amounts to several billions.

The high content of starch, about 60–70% of the whole grain and 65–75% of white flour, means that wheat is often considered to be little more than a source of calories, and this is certainly true for animal feed production, with high-yielding, low-protein feed varieties being supplemented by other protein-rich crops (notably soybeans and oilseed residues).

However, despite its relatively low protein content (usually 8–15%) wheat still provides as much protein for human and livestock nutrition as the total soybean crop, estimated at about 60 m tonnes per annum (calculated by Shewry, 2000 ). Therefore, the nutritional importance of wheat proteins should not be underestimated, particularly in less developed countries where bread, noodles and other products (eg bulgar, couscous) may provide a substantial proportion of the diet.

Protein content

Although wheat breeders routinely select for protein content in their breeding programmes (high protein for breadmaking and low protein for feed and other uses), the current range of variation in this parameter in commercial cultivars is limited. For example, Snape et al. (1993) estimated that typical UK breadmaking and feed wheats differed in their protein content by about 2% dry weight (eg from about 12–14% protein) when grown under the same conditions, which is significantly less than the 2-fold differences which can result from high and low levels of nitrogen fertilizer application. This limited variation in conventional wheat lines has led to searches for ‘high protein genes’ in more exotic germplasm.

Early studies of the USDA World Wheat Collection showed approximately 3-fold variation in protein content (from 7–22%), with about one-third of this being under genetic control ( Vogel et al. , 1978 ). However, the strong environmental impact on protein content (accounting for two-thirds of the variation) underpins the difficulty of breeding for this trait. Nevertheless, some success has been achieved by incorporating sources of variation from exotic bread wheat lines or related wild species.

The former include Atlas 50 and Atlas 66, derived from the South American line Frandoso, and Nap Hal from India. These lines appear to have different ‘high protein genes’ and both were extensively used in breeding programmes in Nebraska with the Atlas 66 gene being successfully incorporated into the commercial variety Lancota ( Johnson et al. , 1985 ). Frandoso and related Brazilian lines have also been successfully exploited in other breeding programmes in the USA ( Busch and Rauch, 2001 ). The Kansas variety, Plainsman V, also contained a high protein gene(s) from a related Aegilops species ( Finney, 1978 ).

The most widely studied source of ‘high protein’ is wild emmer (tetraploid Tr . turgidum var. dicoccoides ) wheats from Israel. One accession, FA15-3, accumulates over 40% of protein when grown with sufficient nitrogen ( Avivi, 1978 ). The gene in this line was mapped to a locus on chromosome 6B (called Gpc-B1 ), which accounted for about 70% of the variation in protein content in crosses ( Chee et al. , 2001 ; Distelfeld et al. , 2004, 2006 ). More recent studies have shown that the gene Gpc-B1 encodes a transcription factor which accelerates senescence in the vegetative parts of the plant, resulting in increased mobilization and transfer to the grain of both nitrogen and minerals (notably iron and zinc) ( Uauy et al. , 2006 ). However, it remains to be shown whether this gene can be incorporated into high-yielding and commercially viable lines.

Protein composition

Of the 20 amino acids commonly present in proteins, 10 can be considered to be essential in that they cannot be synthesized by animals and must be provided in the diet. Furthermore, if only one of these is limiting the others will be broken down and excreted. There has been much debate about which amino acids are essential and the amounts that are required, with the most recent values for adult humans being shown in Table 1 . This table includes a combined value for the two aromatic amino acids, tyrosine and phenylalanine, which are biosynthetically related, and both single and combined values for the two sulphur-containing amino acids: methionine, which is truly essential, and cysteine which can be synthesized from methionine. Comparison with the values for whole wheat grain and flour shows that only lysine is deficient, with some essential amino acids being present in considerably higher amounts than the requirements. However, the lysine content of wheat also varies significantly with the values shown in Table 1 being typical of grain of high protein content and the proportion increasing to over 30 mg g −1 protein in low protein grain ( Mossé and Huet, 1990 ). This decrease in the relative lysine content of high protein grain results from proportional increases in the lysine-poor gluten proteins when excess N is available (for example, when fertilizer is applied to increase grain yield and protein content) and also accounts for the lower lysine content of the white flour (the gluten proteins being located in the starchy endosperm tissue).

Recommended levels of essential amino acids for adult humans compared with those in wheat grain and flour (expressed as mg g −1 protein)

FAO/WHO/UNU (2007) .

Calculated from literature values as described in Shewry (2007) .

The amino acid requirements for infants and children vary depending on their growth rate, being particularly high in the first year of life. Similarly, higher levels of essential amino acids are required for rapidly growing livestock such as pigs and poultry.

Wheat as a source of minerals

Iron deficiency is the most widespread nutrient deficiency in the world, estimated to affect over 2 billion people ( Stoltzfus and Dreyfuss, 1998 ). Although many of these people live in less developed countries, it is also a significant problem in the developed world. Zinc deficiency is also widespread, particularly in Sub-Saharan Africa and South Asia, and has been estimated to account for 800 000 child deaths a year (Micronutrient Initiative, 2006 ), in addition to non-lethal effects on children and adults. Wheat and other cereals are significant sources of both of these minerals, contributing 44% of the daily intake of iron (15% in bread) and 25% of the daily intake of zinc (11% in bread) in the UK ( Henderson et al. , 2007 ). There has therefore been considerable concern over the suggestion that the mineral content of modern wheat varieties is lower than that of older varieties.

This was initially suggested by Garvin et al. (2006) who grew 14 red winter wheat cultivars bred between 1873 and 2000 in replicate field experiments and determined their mineral contents. Plants were grown at two locations in Kansas and significant negative correlations were found between grain yield, variety release date, and the concentrations of zinc in material from both of these sites and of iron in materials from only one site. Similar trends were reported by Fan et al. (2008 a , b ) who took a different approach. Rather than carrying out direct comparisons of varieties in field trials, they analysed grain grown on the Rothamsted Broadbalk long-term wheat experiment. This experiment was established in 1843 and uses a single variety which is replaced by a more modern variety at regular intervals. Analysis of archived grain showed significant decreases in the contents of minerals (Zn, Fe, Cu, Mg) since semi-dwarf cultivars were introduced in 1968. A similar difference was observed between the cultivars Brimstone (semi-dwarf) and Squareheads Master (long straw) which were grown side by side in 1988–1990, the concentrations of Zn, Cu, Fe, and Mg being 18–29% lower in Brimstone. A more recent comparison of 25 lines grown also showed a decline in the concentrations of Fe and Zn since semi-dwarf wheats were introduced ( Zhao et al. , 2009 ) ( Fig. 3 ). Although the decrease in the mineral content of modern wheats is partly due to dilution, resulting from increased yield (which was negatively correlated with mineral content), it has been suggested that short-strawed varieties may be intrinsically less efficient at partitioning minerals to the grain compared with the translocation of photosynthate.

The relationship between the iron content of wholemeal flours from 25 wheat cultivars grown on six trial sites/seasons and their release dates. Taken from Zhao et al. (2009) and reproduced by kind permission of Elsevier.

Such genetic differences in mineral content are clearly relevant to international efforts to increase the mineral content of wheat to improve health in less developed countries. Thus, increasing iron, zinc, and vitamin A contents are a major focus of the HarvestPlus initiative of the Consultative Group on International Agricultural Research (CGIAR) which is using conventional plant breeding ( Ortiz-Monasterio et al. , 2007 ) while other laboratories are using genetic engineering approaches (reviewed by Brinch-Pedersen et al. , 2007 ).

These initiatives are focusing not only on contents of minerals but also on their bioavailability. Iron is predominantly located in the aleurone and as complexes with phytate ( myo -inositolphosphate 1,2,3,4,5,6-hexa-kisphosphate). These complexes are largely insoluble, restricting mineral availability to humans and livestock. The use of transgenesis to express phytase in the developing grain can result in increased mineral availability, particularly when a heat-stable form of the enzyme is used to allow hydrolysis to occur during food processing (reviewed by Brinch-Pedersen et al. , 2007 ).

Guttieri et al. (2004) also reported an EMS-induced low phytate mutant of wheat. This mutation resulted in 43% less phytic acid in the aleurone, but has not so far been incorporated into commercial cultivars. However, previous experience with low phytic acid mutants of maize, barley, and soy bean has shown that they may also have significant effects on yield and germination rates (reviewed by Brinch-Pedersen et al. , 2007 ).

Wheat as a source of selenium

Selenium is an essential micronutrient for mammals (but not plants), being present as selenocysteine in a number of enzymes. However, it is also toxic when present in excess (above about 600 μg d −1 ; Yang and Xia, 1995 ). Cereals are major dietary sources of selenium in many parts of the world, including China ( FAO/WHO, 2001 ), Russia ( Golubkina and Alfthan, 1999 ), and the UK (MAFF, 1997). However, the content of selenium in wheat varies widely from about 10 μg kg −1 to over 2000 μg kg −1 ( FAO/ WHO, 2001 ; Combs, 2001 ).

The concentration of selenium in wheat is largely determined by the availability of the element in the soil. Consequently, wheat produced in Western Europe may contain only one-tenth of the selenium that is present in wheat grown in North America. Thus, a survey of 452 grain samples grown in the UK in 1982 and 1992 showed a mean value of 27 μg Se kg −1 fresh weight ( Adams et al. , 2002 ) compared with 370 μg SE kg −1 fresh weight for 290 samples from the USA ( Wolnik et al. , 1983 ).

Because the import of wheat from North America into Europe has declined over the last 25 years, the intake of selenium in the diet has also decreased, which has resulted in concern in some European countries. One response to this is to apply selenium to the crops in fertilizer (called biofortification), which is practised in Finland ( Eurola et al. , 1991 ).

Unlike iron, selenium is not concentrated in the aleurone, being present wherever sulphur is present. The concentration of selenium in grain from the Broadbalk continuous wheat experiment also appeared to be determined principally by the sulphur availability in the soil (which competes to prevent selenium uptake), with no evidence of decreased levels over time ( Fan et al. , 2008 b ). However, sulphur fertilizer is often applied to wheat to improve the grain quality ( Zhao et al. , 1997 ) and this could clearly have negative impacts on selenium in grain.

The reader is referred to a recent review article by Hawkesford and Zhao (2007) for a detailed review of selenium in wheat.

Wholegrain wheat and health

The consumption of white flour and bread have historically been associated with prosperity and the development of sophisticated roller mills in Austro-Hungary during the second part of the 19th century allowed the production of higher volumes of whiter flour than it was possible to produce by traditional milling based on grinding between stones and sieving (see Jones, 2007 , for a fascinating account of the history of roller milling). However, the increased consumption of bread made from highly refined white flour was not accepted universally, leading to what we would today recognize as a movement to increase the consumption of wholegrain products.

In 1880, May Yates founded the Bread Reform League in London to promote a return to wholemeal bread, particularly to improve the nutrition of the children of the poor, and suggested in 1909 that an official minimum standard of 80% flour extraction rate should be adopted. This was called ‘Standard Bread’. Although we now appreciate the nutritional advantages of wholegrain products, this was not supported by the science of the time and clearly conflicted with the tastes of consumers as well as the economics of bread production. Nevertheless, the League continued to campaign and received scientific support in 1911 when Gowland Hopkins agreed that ‘Standard Bread’ may contain ‘unrecognized food substances’ which were vital for health: these were subsequently called vitamins ( Burnett, 2005 ).

By contrast, Thomas Allinson (1858–1918) had a much greater impact by marketing and vigorously promoting his own range of wholemeal products. He can therefore be regarded as the father of the wholegrain movement and remains a household name to this day in the UK ( Pepper, 1992 ).

We now know that wholegrain wheat products contain a range of components with established or proposed health benefits which are concentrated or solely located in the bran. Hence they are either present in lower amounts or absent from white flour which is derived almost exclusively from starchy endosperm cells. They vary widely in their concentrations. For example, lignans, a group of polyphenols with phytoestrogen activity, are present at levels up to about 10 μg g −1 in wholemeal wheat and twice this level in bran ( Nagy-Scholz and Ercsey, 2009 ), while total phenolic acids in wholemeal range up to almost 1200 μg g −1 ( Li et al. , 2008 ).

The most detailed study of wheat phytochemicals which has so far been reported was carried out as part of the EU Framework 6 HEALTHGRAIN programme ( Poutanen et al. , 2008 ; Ward et al. , 2008 ). This study determined a range of phytochemicals in 150 wheat lines grown on a single site in one year, meaning that the levels of the components may have been influenced by environmental as well as genetic effects. The lines were selected to represent a broad range of dates and places of origin. The choice of phytochemicals focused on those which have putative health benefits and for which cereals are recognized dietary sources. For example, cereals are considered to account for about 22% of the daily intake of folate (vitamin B12) in the UK ( Goldberg, 2003 ) and 36% and 43% of the daily intake in Finnish women and men, respectively ( Findiet Study Group, 2003 ). In the HEALTHGRAIN study the contents of folates in wholemeal varied from 364 to 774 ng g −1 dry weight in 130 winter wheats and from 323 to 741 ng g −1 dry weight in 20 spring wheats, with the content in the former being positively correlated with bran yield and negatively correlated with seed weight (indicating concentration in the bran) ( Piironen et al. , 2008 ).

The quantitatively major group of phytochemicals in the wheat grain is phenolic acids, derivatives of either hydroxybenzoic acid or hydroxycinnamic acid. Epidemiological studies indicate that phenolic acids have a number of health benefits which may relate to their antioxidant activity; the total antioxidant activities of grain extracts and their phenolic acid contents being highly correlated ( Drankham et al. , 2003 ; Beta et al. , 2005 ; Wende et al. , 2005 ).

Cereals are also significant sources of tocols (which include vitamin E) (27.6–79.7 μg g −1 in the HEALTHGRAIN study) ( Lampi et al. , 2008 ) and sterols (670–959 μg g −1 ) ( Nurmi et al. , 2008 ).

The HEALTHGRAIN study also determined the levels of dietary fibre. In wheat, this mainly derives from cell wall polymers: arabinoxylans (approximately 70%) with lower amounts of (1-3)(1-4)β- D -glucans (approximately 20%) and other components. The arabinoxylans also occur in soluble and insoluble forms, with the latter being rich in bound phenolic acids which form oxidative cross-links. These bound phenolic acids account, on average, for 77% of the total phenolic acid fraction and are predominantly ferulic acid. Soluble fibre is considered to have health benefits ( Moore et al. , 1998 ; Lewis and Heaton, 1999 ) which are not shared by insoluble fibre and these may therefore be reduced by the phenolic acid cross-linking. However, insoluble fibre may also have benefits in delivering phenolic antioxidants into the colon: these benefits may include reduction in colo-rectal cancer ( Vitaglione et al. , 2008 ).

The HEALTHGRAIN study showed wide variation in the contents of total and water-extractable arabinoxylans in both white flour and bran fractions ( Gebruers et al. , 2008 ) ( Fig. 4 ). Similarly, Ordaz-Ortiz et al. (2005) showed variation from 0.26% to 0.75% dry weight in the content of water-extractable arabinoxylan in 20 French wheat lines and from 1.66% to 2.87% dry weight in total arabinoxylans. A high proportion of the variation in water-extractable arabinoxylans is also heritable ( Martinant et al. , 1999 ).

Contents of arabinoxylan (AX) fibre in flour and bran of 150 wheat cultivars grown on a single site as part of the EU FP6 HEALTHGRAIN project. (A) Total AX in flour (mg g −1 ); (B) water-extractable AX in flour (%); (C) total AX in bran (mg g −1 ), and (D) water-extractable AX in bran. Prepared from data reported by Gebruers et al. (2008) with permission of the authors.

It is clear from these and other studies that there is sufficient genetically determined variation in the phytochemical and fibre contents of wheat to be exploited in breeding for varieties with increased nutritional benefits.

Allergy to wheat

Both respiratory and food allergies to wheat have been reported.

Respiratory allergy (bakers' asthma) has been known since Roman times (when slaves handling flour and dough were required to wear masks) and is currently one of the most important forms of occupational allergy. For example, it is the second most widespread occupational allergy in the UK and has been reported to affect over 8% of apprentice bakers in Poland after only 2 years exposure ( Walusiak et al. , 2004 ). A wide range of wheat grain proteins have been shown to react with immunoglobulin (Ig)E in sera of patients with bakers' asthma, including gliadins, glutenins, serpins (serine proteinase inhibitors), thioredoxin, agglutinin, and a number of enzymes (α- and β-amylases, peroxidase, acyl CoA oxidase, glycerinaldehyde-3-phosphate dehydrogenase and triosephosphate isomerase) (reviewed by Tatham and Shewry, 2008 ). However, it is clear that the predominant wheat proteins responsible for bakers' asthma are a class of α-amylase inhibitors, also known as CM proteins due to their solubility in chloroform:methanol mixtures ( Salcedo et al. , 2004 ). Furthermore, their activity has been demonstrated by a range of approaches including skin pricks and RAST (radioallergosorbent test) as well as immunoblotting, ELISA, and screening expression libraries with IgE fractions.

The CM proteins comprise monomeric, dimeric, and tetrameric forms, with subunit masses ranging between about 10 000 and 16 000. They differ in their spectrum of activity but all inhibit mammalian and insect α-amylases (including those in some pest organisms) rather than endogenous wheat enzymes. Hence, they are considered to be protective rather than regulatory in function. Eleven individual subunits have been shown to play a role in bakers' asthma (using one or more of the assays listed above) but they differ in their activity, with a glycosylated form of CM16 being particularly active.

Wheat is listed among the ‘big eight’ food allergens which together account for about 90% of all allergic responses. However, the incidence of true (ie IgE-mediated) food allergy is, in fact, fairly infrequent in adults, although it may affect up to 1% of children ( Poole et al. , 2006 ). A number of wheat proteins have been reported to be responsible for allergic responses to the ingestion of wheat products but only one syndrome has been studied in detail. Wheat-dependent exercise-induced anaphylaxis (WDEIA) is a well-defined syndrome in which the ingestion of a product containing wheat followed by physical exercise can result in an anaphylactic response. Work carried out by several groups has clearly established that this condition is associated with a group of ω-gliadins (called ω5-gliadins) which are encoded by genes on chromosome 1B ( Palosuo et al. , 2001 ; Morita et al. , 2003 ; Battais et al. , 2005 ). Mutational analysis has also identified immunodominant epitopes in the ω5-gliadins: short glutamine-rich and proline-rich sequences present in the repetitive domains of the proteins ( Matsuo et al. , 2004 , 2005 ; Battais et al. , 2005 ). However, a number of other proteins have also been shown to react with IgE from patients with WDEIA, including gliadins, glutenin subunits, and related proteins from barley and rye (reviewed by Tatham and Shewry, 2008 ).

Other allergic responses to wheat proteins include atopic dermatitis, urticaria, and anaphylaxis. Not surprizingly, these symptoms have been associated with a number of wheat proteins, most notably gluten proteins but also CM proteins, enzymes, and lipid transfer protein (LTP) (reviewed by Tatham and Shewry, 2008 ).

Comparison of the proteins identified as responsible for the respiratory and food allergy shows significant overlap in their functions (most being storage or protective) and identities (notably gluten proteins and CM proteins).

Intolerance to wheat

Dietary intolerance to wheat is almost certainly more widespread than allergy, notably coeliac disease (CD) which is estimated to affect 1% of the population of Western Europe ( Feighery, 1999 ), and dermatitis herpetiformis which has an incidence between about 2-fold and 5-fold lower than CD ( Fry, 1992 ).

CD is a chronic inflammation of the bowel which leads to malabsorption of nutrients. Like bakers' asthma, CD has been known since classical times but it was only defined in detail in 1887 and its relationship to wheat established by Dicke in the late 1940s ( Losowsky, 2008 ).

A series of elegant studies carried out over the past decade, particularly by Sollid, Koning and co-workers, have established that CD results from an autoimmune response which is triggered by the binding of gluten peptides to T cells of the immune system in some (but not all) individuals with the human leucocyte antigens (HLAs) DQ2 or DQ8, expressed by specialized antigen-presenting cells. The presented peptides are then recognized by specific CD4+ T cells which release inflammatory cytokines which lead to the flattening of the intestinal epithelium. It has also been demonstrated that tissue transglutaminase enzyme present in the epithelium of the intestine plays an important role, generating toxic peptides by deamidation of glutamine residues to give glutamate.

The HLA-DQ2 antigen is present in about 95% of coeliac patients ( Karell et al. , 2003 ) and detailed studies have identified the peptide sequences which are recognized by intestinal T cell lines, using either peptide fractions produced from gluten proteins or synthetic peptides. This has led to the definition of two overlapping immunodominant epitopes corresponding to residues 57–68 (α-9) and 62–75 (α-2) of A gliadin (a form of α-gliadin) ( Arentz-Hansen et al. , 2000 , 2002 ; Anderson et al. , 2000 ; Ellis et al. , 2003 ). Related epitopes were similarly defined in γ-gliadins, corresponding to residues 60–79, 102–113, 115–123, and 228–236 ( Sjöström et al. , 1998 ; Arentz-Hansen et al. , 2002 ; Vader et al. , 2002 a ). Furthermore, Vader et al. (2002 b ) showed that the spacing between glutamine and proline residues determined the specificity of glutamine deamidation and hence peptide activation, and developed algorithms to predict the presence of novel T cell stimulatory peptides in gluten proteins and in related proteins from other cereals.

Less work has been carried out on the determinants of the HLA8-DQ8 associated coeliac disease, which affects only about 6% of patients without HLA-DQ2 and 10% of patients with HLA-DQ2 ( Karell et al. , 2003 ). This has again allowed immunodominant epitopes to be identified in gliadins and glutenin subunits ( van der Wal et al. , 1998 , 1999 ; Mazzarella et al. , 2003 ; Tollefsen et al. , 2006 ) although detailed structural studies indicate that the HLA-DQ2 and HLA-DQ8-mediated forms of the disease may differ in their molecular mechanisms ( Henderson et al. , 2007 ).

The possibility of producing wheat which lacks the coeliac toxic peptides has been discussed for many years but interest in the strategy tended to decline as it became clear that most, if not all, gluten proteins are toxic to at least some susceptible individuals, rather than only the α-gliadins as initially thought. However, Spaenij-Dekking et al. (2005) and van Herpen et al. (2006) have shown that it is possible to identify natural forms of gliadin which have few or no coeliac toxic epitopes, raising the possibility of selecting for less toxic lines of wheat by classical plant breeding. RNA interference (RNAi) technology has also been used to silence the α-gliadin ( Becker et al. , 2006 ; Wieser et al. , 2006 ) and γ-gliadin ( Gil-Humanes et al. , 2008 ) gene families, although some effects on grain-processing properties were observed.

The combination of these two approaches may therefore allow the production of less toxic, if not non-toxic, wheat for coeliac patients without significant loss of the processing properties conferred by the gluten proteins.

Dermatitis herpetiformis is a skin eruption resulting from ingestion of gluten, and is associated with the deposition of IgA antibodies in dermal papillae. These include IgA antibodies to epidermal transglutaminase which is considered to be an important autoantigen in disease development ( Hull et al. , 2008 ).

Other medical conditions related to gluten proteins

There are many reports of the association of wheat, and particularly wheat proteins, with medical conditions, ranging from improbable reports in the popular press to scientific studies in the medical literature. Not surprisingly, they include autoimmune diseases such as rheumatoid arthritis which may be more prevalent in coeliac patients and relatives ( Neuhausen et al. , 2008 ). It is perhaps easier to envisage mechanisms for relationships between such diseases which have a common immunological basis ( Hvatum et al. , 2006 ) than to explain a well-established association between wheat, coeliac disease, and schizophrenia ( Singh and Roy, 1975 ; Kalaydiian et al. , 2006 ) Other reported associations include ones with sporadic idiopathic ataxia (gluten ataxia) ( Hadjivassiliou et al. , 2003 ), migraines ( Grant, 1979 ), acute psychoses ( Rix et al. , 1985 ), and a range of neurological illnesses ( Hadjivassiliou et al. , 2002 ). An association with autism has also been reported ( Lucarelli et al. , 1995 ) with some physicians recommending a gluten-free, casein-free diet ( Elder, 2008 ).

Some of these effects may be mediated via the immune system but effects which are not immune-mediated are notoriously difficult to define and diagnose. However, they could result from the release within the body of bioactive peptides, derived particularly from gluten protein. Thus, gluten has been reported to be a source of a range of such peptides including opioid peptides (exorphins) ( Takahashi et al. , 2000 ; Yoshikawa et al. , 2003 ) and an inhibitor of angiotensin I-converting enzyme ( Motoi and Kodama, 2003 ) (see also reviews by Dziuba et al. , 1999 ; Yamamoto et al. , 2003 ). However, these activities were demonstrated in vitro and their in vivo significance has not been established.

There is little doubt that wheat will retain its dominant position in UK and European agriculture due to its adaptability and consumer acceptance. However, it may also need to adapt to face changing requirements from farmers, food processors, governments, and consumers.

Reducing inputs

Currently grown wheat cultivars require high inputs of nitrogen fertilizer and agrochemicals to achieve high yields combined with the protein content required for breadmaking. For example, UK farmers currently apply 250–300 kg N ha −1 in order to achieve the 13% protein content required for the Chorleywood Breadmaking Process, which is the major process used for breadmaking in the UK. Since a 10 tonnes ha −1 crop containing 13% protein equates to about 230 kg N ha −1 , this means that 50–70 kg N ha −1 may be lost. As fertilizer N currently costs about £1 kg −1 this represents a significant financial loss as well as a loss of the energy required for fertilizer production and may also have environmental consequences.

A number of projects worldwide are therefore focusing on understanding the processes that determine the efficiency of uptake, assimilation, and utilization of nitrogen in order to improve the efficiency of nitrogen recovery in the grain (reviewed by Foulkes et al. , 2009 ).

Reducing the nitrogen requirement of wheat does not only relate to the grain protein content, as an adequate supply of nitrogen is also essential for high wheat yields in order to build a canopy and fix carbon dioxide by photosynthesis. Furthermore, a substantial proportion of this nitrogen is remobilized and redistributed to the developing grain during canopy senescence ( Dalling, 1985 ). Hawkesford and colleagues at Rothamsted Research have targeted this process in order to develop a strategy for improving the recovery of N in the grain, using a combination of biochemical analysis and metabolite and transcript profiling to identify differences in metabolites and gene expression which are associated with efficient mobilization and redistribution ( Howarth et al. , 2008 ). Some of the genes identified in these and similar studies are suitable candidates for manipulation to increase the proportion of the total nitrogen recovered in the grain.

Stability of quality

The increases in temperature and carbon dioxide concentration associated with climate change are expected to have effects on crop development and yield, although the magnitude of these is difficult to predict due to interactions with other factors which may also be affected, notably water availability and populations of pests and pathogens ( Coakley et al. , 1999 ; Semenov, 2008 ). Similarly, although it is generally accepted that higher growth temperatures result in greater dough strength, the precise effects are not clearly understood (see review by Dupont and Altenbach, 2003 ) with heat stress (ie above 30–33 °C) actually resulting in dough weakening and reduced quality ( Blumenthal et al. , 1993 ). A recent review of the effects of CO 2 concentration on grain quality also failed to draw clear conclusions ( Högy and Fangmeier, 2008 ).

Of more immediate interest to wheat breeders and grain-utilizing industries are year-to-year fluctuations in growth conditions, and the frequency and magnitude of such fluctuations are also predicted to increase in the future ( Porter and Semenov, 2005 ). Although some cultivars are generally considered to be more consistent in quality than others, this is largely anecdotal with no detailed scientific comparisons.

Given the recent advances in ‘omics’ technologies it should now be possible to dissect the effects of G×E on grain development and quality, and to establish markers suitable for use in plant breeding. However, this will require substantial resources and a multi-disciplinary approach: by growing mapped populations and lines in multi-site/multi-year trials and determining aspects of composition and quality from gene expression profiling to pilot scale breadmaking.

Wan et al. (2009) have reported the application of this approach using a limited set of seven doubled haploid lines to identify a number of transcripts whose expression profile was associated with quality traits independently of environmental conditions. Millar et al. (2008) also reported a larger study in which three doubled haploid populations of wheat were used to map novel QTLs (quantitative trait loci) for breadmaking and pastry making which were stable over two years field trials, but did not relate quality traits to gene expression profiles.

Wheat is an attractive option as a ‘first generation biofuel’ as the high content of starch is readily converted into sugars (saccharification) which can then be fermented into ethanol. Murphy and Power (2008) recently reported that the gross energy recovered in ethanol using wheat was 66 GJ ha −1 a −1 , but that this only corresponds to 50% energy conversion and that the net energy production is as low as 25 GJ ha −1 a −1 . The same authors also calculated that the net energy production could be increased to 72 GJ ha −1 a −1 if the straw was combusted and the residue after distillation, called stillage or distillers grain and solubles (DGS), was converted to biogas (biomethane).

A major concern about using wheat grain for biofuel production is the high energy requirement for crop production, including that required to produce nitrogenous fertilizer. It is therefore necessary to develop new crop management strategies to reduce inputs ( Loyce et al. , 2002 ) as well as exploiting wheats with low N input requirements combined with high starch contents ( Kindred et al. , 2008 ).

The second major concern is, of course, the impact on international grain prices which may exacerbate problems of grain supply to less affluent populations.

New benefits to consumers

The increasing awareness of the important role of wheat-based products in a healthy diet has been discussed above, focusing on the identification and exploitation of natural variation in bioactive components. However, in some cases the natural variation in a trait may be limited in extent or difficult to exploit and, in this case, other approaches may be required. Currently, the most important target of this type of approach is resistant starch.

Most of the starch consumed in the human diet, including wheat starch, is readily digested in the small intestine, resulting in a rapid increase in blood glucose which may contribute to the development of type 2 diabetes and obesity ( Sobal, 2007 ). However, a fraction of the starch may resist digestion and pass through the small intestine to the colon, where it is fermented to short chain fatty acids, notably butyrate, which may have health benefits including reduction of colo-rectal cancer (as discussed by Topping, 2007 ).

Although the proportion of resistant starch (RS) depends on a number of factors including the effects of food processing, the most widely studied form is high amylose starch. In most species, amylose accounts for 20–30% of starch and amylopectin for 70–80%. However, mutant lines have been identified in a number of species in which the proportion of amylose is increased up to about 40% (e.g. Glacier barley; Yoshimoto et al. , 2000 ).

Selection for high amylose mutants is relatively easy in a diploid species such as barley, but more painstaking approaches are required in hexaploid wheat as mutations in homoeologous genes on all three genomes may be required to have a significant effect on the phenotype. This has been demonstrated very elegantly by Yamamori et al. (2000) who combined mutations in the gene encoding the starch synthase II enzyme (also called starch granule protein 1) that catalyses the synthesis of amylopectin. The resulting triple mutant line contained about 37% amylose.

However, the complexity of starch biosynthesis means that similar high amylose phenotypes can result from changes in other enzymes, with a notable example being the use of RNA interference technology to down-regulate the gene encoding starch-branching enzyme IIa ( Regina et al. , 2006 ). The resulting transgenic lines had up to 80% amylose and increased RS as measured in rat feeding trials. This study demonstrates the power of GM technology, although it remains to be shown that lines with such high levels of amylose will have acceptable yields and properties for milling and processing.

It also remains to be shown that consumers will be prepared to eat bread and other foods produced from GM wheat. The wheat grain and its products have been treated with reverence by humans for millennia and GM wheat may just be regarded as a step too far, even in countries in which other GM crops are currently accepted.

I wish to thank all of my colleagues and collaborators who have contributed to the work discussed in this article, Professor John Snape and the John Innes Institute for providing Fig. 1 and Dr Jane Ward (Rothamsted) for preparing Fig. 4 . Rothamsted Research receives grant-aided support from the Biotechnology and Biological Sciences Research Council of the UK.

Google Scholar

Google Preview

Email alerts

Citing articles via.

• Recommend to your Library

Affiliations

• Online ISSN 1460-2431
• Print ISSN 0022-0957
• Copyright © 2024 Society for Experimental Biology
• About Oxford Academic
• Publish journals with us
• University press partners
• What we publish
• New features  
• Open access
• Institutional account management
• Rights and permissions
• Get help with access
• Accessibility
• Advertising
• Media enquiries
• Oxford University Press
• Oxford Languages
• University of Oxford

Oxford University Press is a department of the University of Oxford. It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide

• Copyright © 2024 Oxford University Press
• Cookie settings
• Cookie policy
• Privacy policy
• Legal notice

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• Plants (Basel)

Factors Affecting the Nutritional, Health, and Technological Quality of Durum Wheat for Pasta-Making: A Systematic Literature Review

Silvia zingale.

1 Department of Agriculture, Food and Environment (Di3A), University of Catania, Via S. Sofia n. 100, 95123 Catania, Italy

Alfio Spina

2 Agricultural Research Council and Economics (CREA)—Research Centre for Cereal and Industrial Crops, Corso Savoia, 190, 95024 Acireale, Italy

Carlo Ingrao

3 Department of Economics, Management and Business Law, University of Bari Aldo Moro, Largo Abbazia Santa Scolastica, 53, 70124 Bari, Italy

Biagio Fallico

Giuseppe timpanaro, umberto anastasi, paolo guarnaccia, associated data.

No new data were created or analyzed in this study. Data sharing is not applicable to this article.

Durum wheat is one of the most important food sources in the world, playing a key role in human nutrition, as well as in the economy of the different countries in which its production areas are concentrated. Its grain also represents a staple and highly versatile ingredient in the development of health foods. Nonetheless, the aspects determining durum wheat’s health quality and their interactions are many, complex, and not entirely known. Therefore, the present systematic literature review aims at advancing the understanding of the relationships among nutritional, health, and technological properties of durum wheat grain, semolina, and pasta, by evaluating the factors that, either positively or negatively, can affect the quality of the products. Scopus, Science Direct, and Web of Science databases were systematically searched utilising sets of keywords following the PRISMA guidelines, and the relevant results of the definitive 154 eligible studies were presented and discussed. Thus, the review identified the most promising strategies to improve durum wheat quality and highlighted the importance of adopting multidisciplinary approaches for such purposes.

1. Introduction

Durum wheat ( Triticum turgidum L. subsp. durum (Desf.) Husn) is a tetraploid species (2n = 28) farmed annually on an estimated cropping area of 18 × 10 6 ha, indicative of nearly 8–10% of the total wheat cultivated area in the world, and a yearly production varying from 35 to 40 × 10 6 Mg [ 1 ]. Generally, it is well suited to locations with low and/or irregular rainfall and repeated heat stress, such as the Mediterranean Basin, where it represents a staple crop and a valuable commodity [ 2 ]. Other major durum wheat producers, besides the countries of the Mediterranean Basin (Turkey, Italy, Morocco, Syria, Tunisia, France, Spain, and Greece), are Canada, Mexico, USA, Russia, Kazakhstan, Azerbaijan, and India, with the first three being the most important exporters [ 2 ]. With a cropping area of 1.3 × 10 6 ha, Italy is the top producer of durum wheat in the EU, providing 4.1 × 10 6 Mg of grain [ 3 ].

Compared with common wheat ( Triticum aestivum L. subsp. aestivum ), which is the largest cultivated cereal crop, durum wheat is distinguished by stronger gluten, grain yellow colour, and longer durability, all of which are necessary for pasta-making [ 4 ]. The latter, however, does not correspond to the exclusive end-product because bread made with durum wheat semolina and pasta made with common wheat flour also exist [ 5 ]. Regarding this, Italy has a considerable role in durum wheat production, mostly as a result of the economic status of the pasta industry, which has pushed the intense breeding work conducted since the beginning of the 20th century [ 6 ].

Thus far, it has not been possible to propose a simple and exhaustive definition of durum wheat quality because it changes depending on the supply chain’s stakeholders (farmer, grain dealer, seed company, milling industry, pasta industry, consumer), and end-use [ 7 ]. Nevertheless, the quality of final products is influenced by the quality of the grain and semolina, which, in turn, are mainly controlled by the genotype but also by the environmental conditions, crop management, and processing techniques. In this regard, Sicignano et al. 2015 [ 8 ] presented a step-by-step manual to simplify the understanding of the most important issues that can affect pasta characteristics.

It is particularly well recognised that the main contributing factors to pasta quality are protein content and gluten properties [ 7 ], which are responsible for dough properties such as dough strength, extensibility, and stability. Indeed, cooked pasta has a distinct structure, consisting of a protein network that firmly entraps starch granules. The structure and composition (amylose content and ratio of large to small starch granules) of such a matrix contribute to the nutritional properties of pasta and make the latter contain slowly digestible starch and have a medium-low glycaemic index [ 9 , 10 , 11 ]. Accordingly, consuming pasta was associated with lower postprandial blood glucose and insulin response and with decreased esophageal cancer risk when compared with bread [ 12 , 13 ].

High levels of yellow pigments and lesser oxidative enzyme activity are additional significant features to consider when making pasta with superior cooking and sensory properties [ 14 ].

Pasta may also be a means of phytochemicals, such as phenolic compounds, vitamins, and minerals, which contribute to health benefits, depending on the raw material used in its preparation. However, reduced information on the content and composition of such bioactive compounds in durum wheat is available [ 15 ]. Indeed, current cereal breeding programs have addressed mainly higher yields and improved technological quality for industrial processing whilst neglecting traits related to nutrition, health, digestibility, and potential allergenicity [ 16 , 17 ]. From this point of view, recent studies on the phytochemicals content of durum wheat products have recently been conducted, underscoring very attractive opportunities for breeding programs to improve wheat nutritional and functional quality [ 18 , 19 , 20 , 21 , 22 ]. Other trends regarded the incorporation of plant-based ingredients, probiotic strains, and/or fibre into pasta products to improve their nutritional value and associated health benefits. However, more research still has to be conducted to evaluate other beneficial compounds in cooked pasta and to estimate more deeply the conditions of the pasta-making process that strongly impact the quality of final products [ 9 ].

In virtue of these considerations, the aim of this systematic literature review was to advance the understanding of nutritional, technological, and health properties of durum wheat grain, semolina, and pasta, through an integrated and holistic approach. To that end, this paper’s authors evaluated all those factors that could, either positively or negatively, affect the quality of the durum-wheat-derived products, such as semolina and pasta. In this respect, according to the author’s knowledge, this is the first time that a systematic literature review (SLR) has been performed on so many quality aspects of durum wheat. In fact, other reviews provided valuable insights on a single or small number of durum wheat quality-related topics, such as breeding history and quality [ 6 , 23 , 24 , 25 , 26 ], human health effects of durum wheat consumption [ 27 , 28 ], enrichment of pasta with non-conventional ingredients [ 29 , 30 ], grain composition and end-use quality [ 31 , 32 ], pasta-making [ 8 , 33 , 34 ] and drying impacts [ 35 , 36 ], and durum wheat colour [ 37 , 38 ], etc. This might be interpreted as a sign of the novelty of this paper and the added value it can bring to the literature by identifying new research priorities and innovative approaches to enhance the overall quality of durum wheat for pasta production.

2. Materials and Methods

This systematic review was conducted following the PRISMA guidelines [ 39 ]. To perform the literature search, Science Direct, Scopus, and Web of Science were screened to retrieve published studies regarding the factors affecting the nutritional, technological, and health properties of durum wheat grain, semolina, and pasta. The following search keywords were used: (“durum wheat”) AND (grain OR semolina pasta) AND (nutritional OR technological OR health quality) AND (effect OR influence OR impact). The above-mentioned databases were chosen for their research builder’s simplicity and wide selection of Life Sciences Journals featuring original research, insightful analysis, current theory, and more.

The obtained articles were screened in a two-step selection process to ensure their relevance:

• In the first step, authors read titles and abstracts and excluded those articles that did not explicitly examine the effects of one or more specific variables/factors on the technological, nutritional, and/or health properties of durum wheat samples of grain, semolina and pasta;
• In the second step, the full texts of the selected articles were critically read, and then were discarded those that (a) did not include original research data; (b) had not implemented appropriate treatments, or had not used accurate analytic methods to simulate and measure, respectively, the effects of the investigated factor on the quality properties of durum wheat; (c) had not been peer-reviewed; and (d) had not been entirely published in English. Thus, the authors did not include review and meta-analysis articles, book chapters, opinion/commentary, and conference papers.

Exhaustive details of the screening process can be found in the PRISMA flow chart ( Figure 1 ). The selected articles were classified concerning details of publication (authors, title, year of publication) and the type of variables/factors investigated.

Flowchart of studies included in the present review ( n - the number of studies), showing the number of articles identified, included, and excluded through the different phases of the systematic review.

3. Results and Discussion

3.1. overview of the reviewed studies.

Among the studies published until 26 June 2022 (data last searched), 257 articles were found from the Scopus (86), Science Direct (31), and Web of Science (140) databases. After removing duplicates, 220 research articles were identified. Then, according to titles and abstracts, 171 papers were recognised as potentially suitable, whereas 49 papers were excluded due to the presence of irrelevant content or information on other qualitative aspects of durum wheat in titles and abstracts. Therefore, the full texts of the remaining 171 papers were scrutinised, and finally, 154 eligible articles were included in the qualitative synthesis. Lists of references (cross-referencing) were also examined to identify relevant studies to complete the search, and 21 additional articles were included.

Figure 2 shows the annual scientific production dealing with the research on factors affecting durum wheat quality: from it, it is possible to note that the number of papers has fluctuated over the last two decades, reaching a maximum of 17 papers in 2019, 2020, and 2021.

Published papers per year, in the period 1989–2022, according to the review’s criteria.

Readers are referred to Figure 3 and Table 1 for a summary of the variables investigated within the studies and to Section 3.2 , Section 3.3 and Section 3.4 for a more critical and exhaustive discussion of the objectives, findings, and recommendations of the different reviewed studies.

Distribution of the durum-wheat quality factors, as explored by the authors of the papers included in the review sample.

Classification of the reviewed studies according to the type of variable investigated.

1 Elaborated by this paper’s team of authors, based on the publication years of the reviewed studies.

As shown in both Figure 3 and Table 1 , research on DW quality has been mainly focused on the following:

• - The experimentation with new pasta formulations;
• - The impacts of the processing;
• - The influence of agronomic management;
• - The selection of genotypes.

In contrast, the effects of environmental stresses and G × E × AM interactions have been poorly studied.

Moreover, as indicated by the study periods in Table 1 , the majority of the factors have been investigated within the last two decades, except for processing ones with a longer history of research, as documented by the first paper published in 1989.

This could be explained considering the interest of both researchers and industry in identifying, through scientifically sound methods, the key elements to improve semolina and pasta quality traits.

3.2. Cropping Factors

3.2.1. genotype effects.

This section was aimed at reviewing papers that evaluated the genotype effects on durum wheat’s technological, nutritional, and health-promoting properties. Indeed, wheat breeding programs were mainly aimed at the development of wheat varieties that provide superior-quality finished products, especially in relation to technological aspects. However, because customers are paying more attention to their health, wheat breeding projects are increasingly designed for enhancing production and endowing derived products with a higher nutritional value [ 27 ]. As a consequence, a number of studies have investigated how G, E, and G × E interactions can influence the expression of different quality features, such as:

• Nutritional and technological properties;
• Other quality features determined by the accumulation of certain metabolites [ 103 ].

Specifically, a significant process of genetic erosion has been triggered by the replacement of wild relatives and landraces with improved varieties, resulting in the loss of possibly beneficial unexplored alleles. The latter could be especially advantageous to improve the currently cultivated durum wheat genotypes’ ability to tolerate biotic and abiotic stresses, as well as their nutritional and technological quality [ 185 ]. Consequently, scientists are devoting increasing resources and work to the search for beneficial alleles and traits from local germplasm collections in order to restore their programs toward food security and quality [ 186 ].

Such a trend was upheld by this review’s findings since many of the considered studies were found to be focused on the screening and/or comparison of durum wheat germplasms, including landraces, old, and modern varieties, related to different quality aspects. For instance, several studies evaluated the genotype effects on durum wheat protein quantity and quality [ 44 , 45 , 47 , 48 ]. Indeed, the latter has always been among the crucial subjects of wheat breeding, with applications mostly focused on the selection of genotypes associated with strong gluten, generally measured with gluten index or rheological tests [ 48 , 187 ]. In their recent two-year field study, De Santis et al. 2017 [ 47 ] carried out a comparative assessment of eight current and seven old Italian durum wheat genotypes to examine the changes in gluten composition and quality raised by the breeding of Italian durum wheat genotypes in the 20th century. Through the discussion of the results, the authors stated that modern genotypes were characterised by a higher gluten quality compared with old cultivars, as measured through the gluten index, and attributed that fact to a significantly major expression of B-type low molecular weight glutenin sub-units (LMW-GS), and a higher glutenin/gliadin ratio. Moreover, there were no significant differences between old and modern genotypes relating to α-type and γ-type gliadins, the former of which is regarded as one of the major fractions determining coeliac disease.

In line with this, De Santis et al. 2018 [ 48 ] also evaluated the grain protein composition of two groups of durum wheat varieties, namely old and modern ones, under Mediterranean environment conditions. As for De Santis et al. 2017 [ 47 ], in this case, modern genotypes revealed a higher relative content of soluble glutenin and a slight decrease in the amount of gliadin fraction, which is generally responsible for gluten-related disorders.

Similarly, Ficco et al. 2019 [ 44 ] assessed gluten peptides release during in vitro digestion as well as the content of potential prebiotic carbohydrates in nine old and three modern durum wheat genotypes. According to their findings, the old genotypes’ whole meal flours are unable to cause a lower exposure to gluten peptides and, in many cases, produce a greater amount of immunogenic and toxic peptides than modern varieties. Regarding possibly prebiotic carbohydrates, instead, even though the modern varieties were richer in total starch, the old genotypes featured a greater amount of resistant starch, always > 1%.

Rises in gluten strength of modern varieties through time were also evaluated by Roncallo 2021 [ 46 ] in a worldwide durum wheat collection and were closely associated with changes in allele composition in the high molecular weight glutenin sub-units (HMW-GS) and LMW-GS, specifically with a progressive replacement of the 20x + 20y banding pattern by the 7 + 8 and 6 + 8 subunits at Glu-B1.

Likewise, another work within those reviewed, namely Fiore 2019 [ 55 ], was aimed at studying the germplasm of durum wheat Sicilian landraces by measuring its agronomic, morphological, and quality features and utilising single nucleotide polymorphisms (SNP) markers. As expectable, within the quality-related traits, they discovered significantly greater protein content (always >16.0%) and weaker gluten (as evidenced by gluten index values ranging from 18.8 to 59.5) in the Sicilian landraces compared with two modern cultivars. Moreover, the protein content and the characteristics related to gluten (dry and wet gluten, water binding in wet gluten, and gluten index) were also the quality traits with the stronger influence in discriminating landraces from the other groups of cultivars used as testers, namely a bread wheat variety, two traditional varieties, and two modern ones.

From that perspective, the dilution effect of proteins and other minor components for the increased amount of carbohydrates may be another possible cause for the decrease in protein content in durum wheat varieties, in addition to the direct genetic effects of the breeding conducted up-to-date [ 49 ]. Hence, the pasta-making industry has to blend different cultivars with high gluten quality to reach proper processing properties. Padalino et al. 2014 [ 49 ] emphasised that the decrease in protein concentration is a real issue for this sector. According to them, even though it is possible to state that these cultivar mixtures could represent a good compromise for the technological quality aspects, the same is not completely true for the nutritional attributes.

To investigate this position, Padalino et al. 2014 [ 49 ] studied six distinct mono-varietal durum wheat cultivars (both modern and old varieties) and evaluated their effects on pasta quality compared with a control pasta made with a commercially available semolina mixture. According to their results, the Cappelli (old variety) pasta performed the highest protein and ash contents; the lowest available carbohydrate content; the lowest glycaemic index; and higher firmness, adhesiveness, and bulkiness values compared with the other spaghetti samples. Therefore, the authors concluded that semolina products based on mono-varietal cultivars could provide durum wheat pasta with a good balance between nutritional and cooking quality.

How genetics can influence gluten quality by determining differences in the amount and composition of glutenins, gliadins, and celiac disease (CD)-triggering peptides was also investigated. In particular, one study among those reviewed, Ronga et al. 2020 [ 113 ], analysed the accumulation of gluten-derived toxic and immunogenic peptides using proteomic techniques in six durum wheat genotypes belonging to the Italian Durum Wheat Network of variety trials. The results showed that whilst toxic peptides’ accumulation was heavily influenced by genotypes, immunogenic peptides expressed marked variation across the different locations, with significant genotype-by-year and genotype-by-site interactions. Moreover, a weak association between grain yield and protein content and toxic and immunogenic peptide accumulation was detected. Overall, the conclusions by Ronga et al. 2020 [ 113 ] were central to specifying the possibility of selecting the agronomic conditions to maximise production in terms of yield, maintain good protein content whilst decreasing the content of peptides implicated in the CD, and consequently reduce the exposure of non-celiac predisposed subjects.

Two of the studies that were reviewed—namely, those by Hogg et al. 2015 [ 50 ] and Botticella et al. 2016 [ 51 ]—introduced another way to obtain healthier pasta with a low glycemic impact. Both papers assessed the effects of SSIIa null mutations on durum wheat grain and pasta quality, as these kinds of mutations are expected to significantly increase the amylose content , thus lowering the glycemic index of pasta and enhancing its quality characteristics. Indeed, the extent of digestibility of starches generally decreases as amylose content increases, although amylose content alone is not the sole predictor of digestibility [ 188 ]. According to Botticella et al. 2016 [ 51 ], the SSIIa null semolina exhibits novel rheological behavior and an elevated content of all major dietary fibre components, including arabinoxylans, β-glucans, and resistant starch. Similarly, Hogg et al. 2015 [ 50 ] assessed the quality technological and sensory characteristics of pasta and discovered that high-amylose line results in lower water absorption, increased cooking loss, shorter cook time, and considerably higher firmness, even after overcooking.

In addition to proteins and starch, the bright yellow colour of durum wheat products is another crucial quality attribute since it appeals to the consumer and has nutritional significance [ 42 ]. Clarke et al. 2006 [ 40 ], one of the studies reviewed here, provided interesting and useful insights about the inheritance of grain or semolina pigment concentration: specifically, their study evaluated seven durum wheat crosses of high by low pigment concentration parents under five field experiments carried out at two or more locations in Western Canada for 2 or more years. Following their findings, the pigment concentration varies depending on the environment, and the inheritance is multigenic and strong when tested in replicated, multi-location, multiyear experiments. This gave Clarke et al. 2006 [ 40 ] the opportunity to suggest employing additional genetic tools, such as DNA markers, to improve the selection of parents for breeding programs.

Another new breeding target, such as the esterification ability for greater retention and accumulation of carotenoids in durum wheat, was suggested by Requena-Ramírez et al. 2021 [ 43 ]. The latter identified different accessions of the Spanish durum wheat landraces germplasm that could offer good chances for carotenoid biofortification projects.

Moreover, as underlined by Ficco et al. 2019 [ 44 ], a new interest in breeding has also been shown for another class of pigments, such as anthocyanins, because of their antioxidant potential. In contrast to yellow pigment, Ficco et al. 2019 [ 44 ] found that anthocyanins expression is highly hereditary, with genotype × year interactions having a less significant impact. Future programs might benefit from this characteristic to improve the antioxidant properties of wheat-derived food products.

As previously reported above, genotype effects on the contents of micronutrients and bioactive compounds were also studied . That is why, although durum wheat primarily serves as a source of carbohydrates and, to a less extent, of proteins, its consumption in the form of wholemeal durum-based products can potentially contribute to enriching human dietary habits with a wide range of beneficial compounds [ 52 ]. Micronutrients, dietary fibre, and phenolic acids are only a few of the bioactive components that are mostly contained in the grain bran and germ tissues [ 15 ].

Mineral elements , for instance, have been proposed to have a vital role in maintaining good health, but they are complexed with phytic acid on kernels and, as a result, are not nutritionally available. Therefore, the selection of cultivars with high mineral density and low phytate content in mature seeds should be a focus of breeding strategies to increase the nutritional value of durum wheat products [ 52 ].

In order to address this, Velu et al. 2017 [ 52 ] examined the variation in grain mineral cations (Ca, K, Mg, Mn, Na, Cu, Zn, and Fe) and P concentrations in a group of durum wheat genotypes representative of the Mediterranean old and modern germplasms. Specifically, they assessed how dwarfing genes affected grain Zn, Fe, Mn, and Mg contents, as well as kernel weight. The results allowed Velu et al. 2017 [ 52 ] to observe that the dwarfing genes were associated with a decrease in all the minerals and with a negative effect on kernel weight. In particular, Velu et al. 2017 [ 52 ] concluded that such changes in micronutrient concentrations are mostly caused by the associated pleiotropic effects of dwarfing genes on increased biomass partitioning and higher harvest index. Such dilution of minerals concentration as yield potential rises highlighted the difficulty of using wild relatives to improve modern varieties and, therefore, the need to screen landraces, which tend to have a better agronomic type than wild relatives [ 189 , 190 ].

Within the reviewed literature, the research performed by Hernandez-Espinosa et al. 2020 [ 15 ] was precisely in this direction. These authors, indeed, examined the contents of arabinoxylan, phenolic acids, phytic acid, and micronutrients in a sample of eighty-two durum wheat landraces (thirty-nine Iranian and forty-three Mexican). Their findings showed that landraces varied widely in all of the quality traits, with some cultivars being characterised by a desirable combination of such attributes. The latter landraces were proposed as a useful genetic resource to improve nutritional quality, particularly the quantity and bioavailability of dietary fibres and micronutrients.

Regarding dietary fibres , important findings concerning the role of genotype on the arabinoxylans content were reported by Ciccoritti et al. 2011 [ 106 ]. Their experiment was carried out with a large collection of Italian durum wheat cultivars grown in two different Italian sites for two years to assess the influence of genotype and environmental factors on the arabinoxylans’ content and extractability. Their findings confirmed the genetic control of arabinoxylans’ structural variability and differences among genotypes for arabinoxylan fractions. Moreover, the environment and its interaction with genotype appeared to be important sources of variation for arabinoxylans in the whole grain. However, the combined effect (G × E) contributed to the total variability in a lower way compared with genotype and environment alone.

Furthermore, a number of studies considered in this review were focalised on the genotype effects and/or genotype x environment effects on phenolic compounds ’ content and quality [ 18 , 19 , 20 , 58 , 60 , 104 , 107 , 108 , 111 , 112 ]. Specifically, the interest in such grain phytochemicals is linked to their strong antiradical activity, which can contribute to protecting humans against various degenerative diseases [ 20 ].

For instance, the variability for individual and total phenolic acids contents within a large set of tetraploid wheat, including the Triticum subspecies durum, turanicum, polonicum, carthlicum, dicoccum , and dicoccoides , was recently assessed by Laddomada et al. 2017 [ 58 ]. Compared with other subspecies, durum wheat cultivars have higher average contents of total phenolic acids (from 550.9 to 1701.2 lg g −1 dm), which were also more stable over time. Interestingly, they found a significant genotype effect for both total and individual phenolic acids, as well as a moderately high ratio of genotypic variance to the total variance, indicating that a breeding approach to increase phenolic acids concentration in durum wheat could be taken into consideration.

Moreover, Martini et al. 2015 [ 112 ] assessed the level of total antioxidant capacity in ten durum wheat genotypes grown in the same experimental field over three successive cropping years. They also measured the content of phenolic acids and of total phenolics, both occurring as soluble free, soluble conjugated, and insoluble bound forms, as well as the yellow-coloured pigments. The findings of their study highlighted that in contrast to the content of phenolic acids and total phenolics, which appeared to be most affected by the environment and then by the genotype, yellow-coloured pigments and total antioxidant activity are mainly influenced by genetic factors. This called for programs aiming at selecting genotypes naturally rich in antioxidant compounds, also by choice of the more suitable growing area.

In line with this, Dinelli et al. 2009 [ 20 ], Dinelli et al. 2013 [ 19 ], Di Loreto et al. 2018 [ 18 ], and Truzzi et al. 2020 [ 60 ] determined the qualitative profiles of phenolic compounds (free and bound fractions) in diverse wheat, comprised of old and modern durum wheat genotypes.

Dinelli et al. 2009 [ 20 ] evaluated such grains’ functional components in two old and seven modern Italian cultivars of durum wheat cropped in the same location and years. No significant differences were detected among the investigated cultivars as regards the amounts of total phenolic and flavonoid compounds, but a remarkably qualitative diversity in the phytochemical profiles between old and modern varieties was noted: in particular, the mean numbers of total compounds and total isomers were significantly higher in old genotypes than in modern ones. Thus, landraces were indicated as a rich source of genetic diversity, especially for bioactive compounds, allowing the authors to suggest their uses in the formulation of both standard and specialty functional food products.

Along with the phytochemical composition, Dinelli et al. 2013 [ 19 ] also assessed the agronomic performances and the nutritional value of several old and modern durum wheat genotypes grown under low input farming conditions. No clear distinction between the two groups of varieties was observed in terms of grain yield, demonstrating how the productivity gap, often existing between dwarf and non-dwarf genotypes, is significantly narrowed when they are managed under low inputs. All the examined genotypes also had high protein amounts and provided phytochemicals such as dietary fibre, polyphenols, flavonoids, and carotenoids. On the other hand, Di Loreto et al. 2018 [ 18 ] discovered remarkable quantitative variations between old and modern genotypes for their phenolic acids content and composition, as well as for the antioxidant activities, with significantly higher values obtained for the old ones. Furthermore, since the varieties were grown in the same area and year, the observed differences were to be attributed to a genetic influence. In light of this, the authors hypothesised that old and modern durum wheat genotypes might have different secondary metabolite biosynthesis pathways. When it comes to the bound forms of polyphenols and flavonoids, as well as to the antioxidant activity, such genetic control was also supported by the results reported in Di Silvestro 2017 [ 107 ], although a significant interaction between cropping year and location was found for the free forms of phenolics. In line with this, Bellato et al. 2013 [ 104 ] found that the environment and genotype were the primary determinants of the phytochemical profiles of durum wheat grains, with their interactions (E × G) playing a much lower role in the overall variability.

Following Truzzi et al. 2020 [ 60 ], this research line, which aims at distinguishing wheat varieties based on their health-promoting compounds profiles, may open the way and support new approaches for the genetic improvement of the genus Triticum and the development of nutraceutical cereal-based ingredients and products.

In this regard, Truzzi et al. 2020 [ 60 ] combined the assessment of the polyphenol content and antioxidant activity with the use of cell models systems, where the polyphenols extracted from different soft and durum wheat genotypes involving modern and old varieties were tested for their ability to repair intestinal tissue damages. The results showed differences between soft and durum wheat phenolic compounds, implying a significant genotype influence on the proprieties of wheat extracts. Moreover, both modern and old varieties’ polyphenols had positive effects on cells. That is why Truzzi et al. 2020 [ 60 ] concluded that combining old and modern varieties in specific crosses could be a useful strategy for developing nutritionally improved wheat-based products to be integrated into diets with protective functions against chronic and inflammatory diseases. Nevertheless, human intervention studies are required to validate these results and possibly support health claims regarding the functional properties of wheat varieties.

Finally, the genotype can also influence the volatile composition of durum wheat kernels with consequences on semolina and pasta products [ 53 , 54 ]. Both Beleggia et al. 2009 [ 54 ] and Mattiolo et al. 2017 [ 53 ] found considerable differences in terms of composition and amount of volatile compounds (especially of ketones, aldehydes, and alcohols) among durum wheat cultivars, using headspace solid-phase micro-extraction (HS-SPME) and the GC–MS. Such research opened up the selection of varieties based on the typical flavour they could give to the respective monovarietal pasta and pointed out the efficacy of HS-SPME in conjunction with GC-MS for such purposes.

3.2.2. Environmental Effects

In this section, the influence of different environmental stresses is widely and critically described through the evaluation of the reviewed studies’ results. Additionally, the exacerbation of environmental stresses due to climatic change underway is expected to heavily affect not only crops’ productivity but also the chemical composition and, thus, the quality of the products, potentially leading to threats to food security [ 66 , 191 ]. This is even more evident for durum wheat, as its areas of production are characterised by drought and extreme temperatures [ 192 , 193 , 194 ].

Durum wheat’s quality features are generally strongly influenced by environmental conditions , with growing zones, latitudes, and moisture regimes showing the greatest impacts [ 44 ]. For instance, one study suggested the possibility that the expected values of gluten index and colour parameter b* (CIELAB System) related to yellow, particularly important for pasta-making, could be accurately estimated based on meteorological variables, such as rainfall, mean temperature, and the number of heat days [ 43 ].

Among environmental stresses, the impact of high temperature during grain filling on the qualitative characteristics of wheat has been long recognised [ 46 ].

The first paper dealing with this topic among those reviewed was that of Corbellini et al. 1997 [ 46 ], who found that the occurrence of very high temperatures (in the range of 35–40 °C) during grain filling substantially affects dry matter and protein accumulation in the different parts of the plant. Specifically, according to their results, heat stresses that came late in grain filling determined a “dough weakening” effect, which may reduce the commercial value of the production.

However, there exist different typologies of heat stresses during wheat grain filling, and they can give rise to different effects on durum wheat quality, depending on the timing (days after anthesis) and duration.

Recently Sissons et al. 2018 [ 50 ] pointed out that late sowing (two months later than normal sowing) had positive effects on increasing protein content, dough quality indicators, and pasta end-use traits since it exposed the crop to more days at higher temperatures (around 30 °C). However, the same practice determined a reduced yield, grain weight, test weight, and milling yield [ 50 ].

In line with this, Cosentino et al. 2019 [ 70 ] investigated the effect of post-anthesis heat stress on several durum wheat genotypes, including old and modern varieties and a Sicilian landrace. According to their results, advances in main phenophases significantly decreased kernel weight and grain yield, whereas grain protein content increased. Moreover, genotypes responded differently to heat stress, as evidenced by the net photosynthesis, transpiration rate, instantaneous water use efficiency, and dry matter accumulation in kernels.

In addition to the influence on protein quantity and quality, heat stress can also have strong effects on grain composition in terms of the compounds that are beneficial or detrimental to human health. In this regard, an interesting study was carried out by de Leonardis et al. 2015 [ 71 ], looking at how the nutritional value, antioxidant capacity, and metabolic profile of different durum wheat genotypes can be affected by heat stress, in particular by the exposure at 37 °C for five days after the flowering stage. Following them, heat-stress effects can have diverse consequences on the accumulation of bioactive compounds, which can result in either beneficial or detrimental effects on human health in relation to the wheat genotype and the environmental conditions that occur during the crop cycle.

In line with Sissons et al. [ 50 ] and de Leonardis et al. 2015 [ 71 ], Rascio et al. 2015 [ 69 ] also evaluated the effects of heat stress on the potentially health-beneficial compounds of two old durum wheat genotypes and a modern cultivar, sown in winter and spring. As for de Leonardis et al. 2015 [ 71 ], the results evidenced that genotypic effects had the most significant role in the determination of grain quality and that the genotypes do not always react the same way to environmental changes. Specifically, spring sowing changed the grain composition of polyphenols and further differentiated the genotypes in terms of carotenoids, high-quality starch, and sulfur compounds, with variations depending on the genotype. Consequently, the timing of sowing could be changed to achieve the desired enrichment of cereal-based foods according to the end-use and type of health benefits required by consumers [ 69 ].

There is less research on the impacts of drought durum wheat quality than there is on heat stress, whether it is caused by erratic or deficient rainfall or limited irrigation [ 67 ]. Among the reviewed articles, Flagella et al. 2010 [ 72 ] and Giuliani et al. 2015 [ 55 ] focused on water deficit or drought stress effects on durum wheat protein composition. Investigating that was particularly important because the strength and elasticity of the wheat are strongly influenced by the insoluble fraction of wheat grain protein, which is made up of gliadins and glutenins. Specifically, Flagella et al. 2010 [ 72 ] found that the timing of stress occurrence varied the effects of water deficit on the technological quality and protein composition. When a water deficit persisted through the growing season, an increase in protein content and a drop in the HMW-GS/LMW-GS ratio were detected by the authors. Instead, when terminal water stress occurred in grain filling, an improvement in gluten strength was observed. Consistent findings were also determined in the study carried out by Giuliani et al. 2015 [ 55 ], who used a proteomic approach to evaluate changes in storage protein composition under water stress of two Italian modern durum wheat cultivars: in particular, LMW glutenin subunits decreased under water stress, whilst gliadin-like (especially α-gliadins) proteins increased.

Furthermore, some studies among those reviewed focused on the combined effects of heat and drought stress on several nutritional and technological characteristics of durum wheat [ 65 , 67 , 109 , 195 ].

Specifically, Li et al. 2013 [ 67 ] examined the effects of heat and drought stresses on the technological durum wheat quality of nine different cultivars, each with a different set of quality attributes. According to their findings, drought tends to enhance gluten strength, whereas heat stress tends to reduce it. Moreover, as in Corbellini et al. 1997 [ 46 ], a “weakening” effect of heat stress on the gluten strength of durum wheat was reported. Moreover, Gagliardi et al. 2020 [ 109 ] evaluated the variation in the gluten protein assembly of four durum wheat genotypes with respect to various nitrogen levels and growing seasons. Significant lower yield and a higher protein concentration were observed in the year characterised by a higher temperature at the end of the crop cycle. Moreover, the effect of the high temperatures on protein assembly was different for the genotypes in relation to their earliness. Phakela et al. 2021 [ 65 ], instead, aimed at assessing the effects of drought and heat stress (both in moderate and severe ways) on the variation in gluten proteins in six durum wheat cultivars with the same HMW and LMW glutenin subunit composition. Overall, Phakela et al. 2021 [ 65 ] observed that sulfur-rich proteins (α/ β- and γ-gliadins, and LMW glutenins) were more sensitive to heat and drought conditions, except for the α-gliadins, which were significantly increased by all stress treatments. Moreover, in their study, the γ-gliadin, which was highly influenced by genotype, has a positive effect on alveograph characteristics under all conditions, thus indicating that selection for γ-gliadin will be successful in increasing dough strength.

Recently, Erice et al. 2019 [ 49 ] simulated future climatic conditions, consisting of elevated CO 2 and drought , to test their effects on grain quality features and water usage efficiency of two varieties of durum wheat, namely a landrace and a modern variety. The authors found that the two cultivars showed opposite behavior regarding kernel quality and water use efficiency when exposed to the projected future atmospheric CO 2 levels. Both varieties provided similar protein amounts when cultivated under ambient CO 2 and full water availability, whilst they responded differently to elevated CO 2 . In particular, the modern genotype’s protein content decreased in both water regimes, whilst the landrace’s one did not change. On the other hand, better agronomic performances and technological properties were observed for the modern variety under the projected future elevated CO 2 and drought conditions. Despite this, landraces were proposed to be incorporated into breeding programs due to their lower susceptibility to losing the kernel protein nutritional value [ 66 ].

Equally, Soba et al. 2019 [ 56 ] revealed that important modifications of grain metabolism due to CO 2 emissions increases could have implications for its nutritional quality. Indeed, the growth of durum wheat under elevated CO 2 conditions reduced the N content as well as the protein and free amino acids content, with a remarkable loss in glutamine, which is the most prevalent amino acid in grain. Indeed, approximately 40% of gluten proteins is represented by glutamine, and the decline in its concentration could have pervading consequences for protein synthesis and final grain composition and quality [ 56 , 196 ].

3.2.3. Agronomic Management Effects

The purpose of this section was to discuss the current agronomic management practices adopted within durum wheat production systems and explore how they can lead to improvements or losses in quality aspects.

The main topics covered in the reviewed articles included:

• Cropping systems;
• Crop sequences;
• Prevalent management practices (sowing date, tillage, and fertilisation).

Concerning cropping systems , some studies compared the effects of conventional versus organic farming practices on different quality attributes of durum wheat grains and semolina pasta.

Interesting results were obtained by Quaranta et al. 2010 [ 77 ] in three years of trials for six durum wheat varieties grown under conventional and organic cropping systems in different Italian regions. According to them, the organic yields were significantly lower (−16%) than those obtained in conventional cropping, excluding the southern locations where the difference was lower (−5%). Similar data were obtained for grain protein, even if the gap between conventional and organic systems was less than 1.0% [ 3 ]. Regarding the levels of deoxynivalenol (DON) contamination, the organic cropping system instead allowed for good results not only in Southern Italy, where fungal infections were limited but even in the locations of Central Italy, which are more exposed to the risks of hazardous fungal pathogens attacks. This fact was mainly attributed to the rotations with non-host Fusarium crops such as leguminous. As a result, Quaranta et al. 2010 [ 77 ] proved the importance of both southern vocational areas for durum wheat farming and sound agronomic practices for the control of Fusarium and associated mycotoxins contamination.

Comparably, Fagnano et al. 2012 [ 78 ] found that organic production determined a reduction in protein content, gluten content, and quality, thus stressing the core problem for the organic sector, which is reduced protein accumulation. Despite this, one of the varieties under study achieved the highest quality level in both conventional and organic cropping systems, thereby confirming that the choice of an adaptable genotype can allow for gaining satisfactory outcomes even under the organic regime. In addition, the authors recommended also rotating durum wheat with legume crops to ensure the necessary N is available at sustainable costs.

Further concerns have been raised regarding the use of nonselective and broad-spectrum herbicides, such as glyphosate, in conventional farming systems. Indeed, glyphosate and aminomethylphosphonic acid (AMPA) residues are often detected on soil, water bodies, and food products, causing detrimental effects on environmental and human health [ 197 ].

However, there was debate about whether the use of glyphosate should be banned, restricted, or encouraged as a result of the frequently contradictory opinions of scientists, regulatory organisations, the general public, and the different regulations adopted on a global scale. For instance, the International Agency for Research on Cancer (IARC) in 2015 reclassified glyphosate as a Category 2A (probable carcinogen), whereas the Joint Food and Agriculture Organization, the European Food Safety Authority, and the European Chemicals Agency kept on confirming glyphosate as not posing a genotoxic or carcinogenic risk to humans [ 198 ]. As a consequence, although the Codex Alimentarius allowed a residues limit of 30 ppm of glyphosate for wheat, some countries have lowered the permitted limits [ 24 ]. In Italy, for example, the pasta industry accepts a limit of under 10 parts per billion to meet the increasing consumers’ requests for low or zero chemical residues [ 24 ].

Regarding the effects of glyphosate application on durum wheat quality, Manthey et al. 2004 [ 98 ] investigated the impact of glyphosate on wheat quality traits and concluded that its pre-harvest application could decrease hectolitre weight, thousand kernel weight, and kernel size. Other studies analysed the effect of glyphosate application on the chemistry of gluten proteins and shikimic acid accumulation [ 99 ] and on starch chemistry [ 100 ]. The results from Malalgoda et al. 2020 [ 99 ] indicated that pre-harvest glyphosate spraying decreases the molecular weight of SDS extractable and unextractable proteins whilst increasing the amount of shikimic acid accumulation. Thus, [ 99 ] advocated for investigating the changes related to the pre-harvest glyphosate spraying to provide insights on how correctly apply it without causing any related negative effects on the functionality of proteins. Similarly, Malalgoda et al. 2020 [ 100 ] studied the effect of glyphosate spraying timing (recommended stage vs. early stage) on wheat starch chemistry and discovered that the starch structural properties and thermal behavior were altered, especially if applied at the soft dough stage.

The type of cropping systems also influences the health-promoting properties of durum wheat: these evaluations were carried out in three studies among those reviewed, Nocente et al. 2019 [ 76 ], Fares et al. 2019 [ 108 ], and Pandino 2020 [ 75 ].

Nocente et al. 2019 [ 76 ] investigated the effect of the cropping system (conventional vs. organic) and tillage system (conventional vs. reduced tillage) on kernel bioactive compounds of durum wheat in a two-year study. Their results stressed the importance of growing year and management: indeed, high rainfall in the first year of the experiment was likely responsible for the loss of soil organic matter, annulling the differences between the two agronomic management systems; conversely, when rainfall was regularly distributed, the differences were substantial, with higher alkylresorcinols and total phenols contents in organic than in conventional farming. With regard to tillage intensity, alkylresorcinols and total phenols were positively affected by deeper tillage in organic management, whereas yellow pigments and total antioxidant activity were favored by reduced tillage in conventional farming.

The effects of organic and conventional cultivation under equivalent nitrogen fertilisation (as organic N and mineral N for organic and conventional cultivation) on antioxidant content and composition and quality traits were assessed by Fares et al. 2019 [ 108 ] using several old genotypes of three different kinds of wheat ( T. dicoccum, T. durum, T. spelta ). Compared with conventional farming, organic farming positively contributed to test weight, whilst other quality traits, such as protein and gluten contents and sodium dodecyl sulphate (SDS) sedimentation volume, were 19.2%, 9.3%, and 22.7% lower, respectively. Despite the fact that the protein content was lower under the organic regime, it was still high: thus, with adequate organic nitrogen fertilisation, the technological quality traits of organic flours can be sustained. At the same time, although free and bound phenolic acids did not significantly differ, total phenolic content (TPC) was significantly higher for organic versus conventional farming.

Coherent results were observed by Pandino 2020 [ 75 ] in examining the effects of cropping systems on the level of some nutrients, phytochemical compounds, and antioxidant activity, as well as on the yield and the rheological indices. According to them, the conventional cropping system appeared to determine better performance than the organic ones in terms of grain yield, protein content, alveograph dough strength (W), and wet gluten and microelements levels (Cu, Fe, Mn, Zn). On the contrary, total phenols content and antioxidant activity were highest in the organic cropping system. This could help to choose genotypes able to provide higher daily intakes of minerals and health-promoting compounds.

Concerning tillage practices , a renewed interest in the effects of the transition from conventional to conservation management was found in the reviewed studies. This was due to some concerns that needed to be addressed when conservative agriculture was first introduced, such as the possible diffusion of durum wheat diseases, unstable yields, and grains’ technological quality [ 199 ].

Specifically, Calzarano 2018 [ 79 ] looked at the effect of different patterns of soil treatments and crop sequences (conventional vs. zero tillage; monocropping vs. crop rotation with faba bean) on productivity, grain quality traits as well as on disease incidence and severity in durum wheat. The results of two years of data from a long-term experiment revealed that the conservation agriculture techniques (zero tillage + crop rotation) improved the grain yields, protein accumulation, gluten quality, and colour appearance. The highest grain yields associated with zero tillage and durum wheat–faba bean rotation were also explained by Pagnani 2019 [ 80 ], who observed an increased number of ears m −2 , and a higher N-remobilisation to the grains.

Regarding tillage practices, another interesting study comes from Ruiz 2019 [ 81 ], who made the assumption that conservation agriculture demands varieties capable of sustaining good yields with few inputs in the face of unpredictable climatic conditions. Therefore, this study analysed the agronomic and morphological characteristics, as well as technical quality features of several bread and durum wheat genotypes, including landraces, intermediate and modern varieties, grown under minimum tillage, and no-tillage. According to their findings, a positive influence of no-tillage on traits related to grain and biomass yield was evidenced, whereas the tillage system and its interactions with year and with genotype did not have any relevant effect on quality traits. This makes it possible to assume that the quality of any variety will be unaffected, whatever the conservation tillage practice is used [ 81 ].

Regarding the effects of fertilisation practices , it should be noted that the latter accounted for the majority of studies dealing with agronomic management factors. This was not surprising to the authors’ opinion since researchers have always been interested in the modification of the quality characteristics of wheat grains influenced by basic fertilisation and are recently more and more debating on how to improve the cost-effectiveness and environmental sustainability of such fertilisation supply [ 194 , 200 , 201 , 202 ].

The reviewed studies particularly investigated different aspects inherent to the use of fertilisers, such as the nutrient, rates, times, and method of application, and with regard to diverse quality aspects.

N fertilisation is a common practice adopted to increase yield and grain protein content. The need for increased protein content is due to the extensive use of continuous durum wheat and durum wheat-fallow systems, which tend to decrease this content below 13%, the minimum level requires for pasta-making. Moreover, high-yielding modern cultivars have prompted an increase in the use of N fertilisers since they need a higher fertilisation rate than old ones to reach their maximum grain yield and protein content [ 6 ].

Among the reviewed studies, the first paper to deal with N fertilisation effects on grain yield and grain protein content was carried out by Colecchia et al. 2013 [ 86 ], who experimented with different N application rates and timing on six durum wheat cultivars. Their results showed that N application at the sowing date did not impact the cultivars’ productivity and quality, suggesting the possibility of postponing the fertilisation and using it only during the critical phase for durum wheat, that in semiarid conditions coincides with the end of tillering and beginning of stem elongation. At the same time, higher N fertilisation levels did not cause any meaningful increase in yield and protein because it is likely that the excess N is leached during the period of higher rainfall, causing environmental and economic losses.

Morari et al. 2018 [ 88 ] evaluated the effects of different N fertilisation rates on protein quantity and also quality. In that case, higher N fertilisation levels were found to induce high protein contents and improve gluten proteins, as well as technical quality, but this practice was discouraged due to its possible contribution to the soil, air, and water pollution risks. Moreover, as stated by Marinaccio et al. 2016 [ 92 ], the effectiveness of N fertilisation on protein content and other quality traits depended also on soil texture and rainfall during growing seasons. Therefore the management of N fertiliser should be carried out also considering these interactions.

Another interesting study from Pasqualone et al. 2014 [ 203 ] evaluated the effects of the use of composted sewage sludge , as it is and in combination with common mineral fertilisers, on durum wheat productivity, technological quality, and antioxidant properties. The authors evidenced that sewage sludge application greatly increased the productivity as well as the concentration of phenolic compounds, antioxidant activity, and technological quality of durum wheat whole flours. With regard to phenolics and antioxidant activity, a further increase can be achieved by employing a combination of composted sewage sludge and mineral fertilisation.

One more approach of durum wheat nutrition management, not conflicting with environmental protection, deals with the application of plant biostimulants , able to modulate several functions of the plant, such as nutrient efficiency, abiotic stress tolerance, humification, and many others. Moreover, Pichereaux et al. 2019 [ 96 ] studied and reported interesting results about the influence of marine (DPI4913) and a fungal (AF086) biostimulants applied to leaves on grain yield, protein concentration, and composition of durum wheat grains. Indeed, both types of biostimulants induced an increase in grain yield and protein quantity, as well as a modification of the protein composition. Specifically, the proteome analysis allowed the authors to identify 50 proteins that were differentially represented after the treatments, all of them involved in metabolic reactions and processes, including storage, regulation processes, and defense response against abiotic and biotic stresses.

Similarly, Pačuta 2021 [ 95 ] studied the impacts of brown seaweed-based and humic substance-based biostimulants on yield and grain quality. The biofertilisation was realised three times during the vegetation for both substances, and it has increased the grain yield compared with the non-fertilised variant. However, the best results were obtained on the humic acid variant. Moreover, the study found no evidence of a statistically significant effect of biofertilisation on the quality traits (protein and gluten content, vitreousness, falling number, bulk density), even if the latter always maintained or slightly exceeded good levels.

Lastly, it is undiscovered that good effects on nitrogen supply and durum wheat quality can be obtained by adopting agroecological practices, such as crop rotation and intercropping, especially with legume crops . Indeed, besides the advantages of using leguminous species as a fundamental tool for the maintenance and management of soil fertility, intercropping durum wheat with grain legumes is known to increase the protein content in the durum wheat grains, so it could be used to enhance the quality [ 101 , 102 , 204 ].

Some studies were instead focused on fertilisation and biofortification for some critical micro-nutrients that are currently present in limited concentrations in the soils or that are difficult to be accumulated in the grain, thus leading to malnutrition.

For instance, Sulphur (S) deficiency in agricultural soils has become widespread in many European countries, and S fertilisation in the study of Ercoli et al. 2011 [ 93 ] showed positive effects on grain quality and pasta quality for all measured rheological and technological features, such as dry gluten, SDS volume, and alveograph indices.

Similarly, Abdoli et al. 2016 [ 84 ] addressed another important micronutrient deficiency, the one related to Zinc (Zn) in common and durum wheat growing in calcareous soils. According to this study, both soil and foliar zinc application methods could improve yield and grain Zn concentration. However, bread wheat generally had better agronomic traits; grain yield; and Zn, Fe, Cu, and Mn concentrations in grain compared with durum wheat. In addition, different Zn treatment methods also decreased the phytate content, the latter being acknowledged to be chelating of Zn. For these reasons, the use of zinc fertilisers appeared to be a reasonable temporary solution to alleviate zinc deficiency. With regard to the latter problem, another team of authors, namely Tran et al. 2019 [ 90 ], pointed out that the bioavailability of Zn, as well as that of iron (Fe) in the grain of cereals, can be overestimated by failing to consider the abundance of phytic acid. In this work, the authors specifically looked at the growth and nutritional responses of durum wheat to arbuscular mycorrhizal fungi and to diverse soil Zn concentrations. It was observed that the inoculation increased the concentration of phytic acid in durum wheat grain whilst having no effect on the concentration of Zn and Fe: this consequently reduced the predicted bioavailability of grain Zn and Fe, which could result in a decrease in the nutritional quality of the grain.

Likewise, Melash et al. 2019 [ 94 ] conducted a field experiment to evaluate the effect of foliar micronutrient application on grain yield and quality traits of durum wheat, and in line with other authors, observed that the application of ZnSO 4 and FeSO 4 has increased the concentrations of both elements in the grains, although with differences among genotypes. Thus, they confirmed that agronomic biofortification could be a strategy to overcome health issues related to Zn and Fe deficiency if applied to varieties with well-known genetic responses to such treatment.

The other two studies investigated the use of Selenium (Se) to improve durum wheat agronomic performances and nutrient uptake and the quality of the derived food products [ 87 , 91 ]. De Vita et al. 2017 [ 87 ] carried out two field experiments over three growing seasons to evaluate Se foliar fertilisation at various rates and timing of application on four durum wheat varieties for pasta-making. Their findings confirmed the effectiveness of foliar Se fertilisation in increasing Se concentrations and highlighted more significant responses to the treatment in landraces and old varieties compared with the modern ones. Moreover, the increased Se content in the grains did not modify grain quality features, as well as the sensory features of the final pasta. Similarly, Ayed et al. 2022 [ 91 ] explored the effect of Se foliar supply on grain yield and technological quality traits of different durum wheat genotypes, including advanced lines and modern varieties grown under semi-arid and sub-humid regions in Tunisia. As for De Vita et al. 2017 [ 87 ], Se responses were genotype-specific both within and among the two studied areas, and Se foliar application was confirmed to be a safe way of increasing grain yield and quality.

3.3. Technological Factors

The overall quality of durum wheat pasta also depends on many technological factors, dealing with the main processing operations that are carried out to transform grains and semolina. Hence, it is to remark that each kind of food technology, according to its variables, such as working principles, time, temperature, and level of intensity, can determine both enhancements or detriments of the nutritional and sensory properties of the final product. With regard to the pasta sector, scientific research is constantly evolving, both with studies on the improvement of the raw material and on the innovation of processing plants [ 205 ]. As stated by Hidalgo et al. 2010 [ 130 ], such effort is needed to identify the best strategies to control the degradation of nutrients and bioactive compounds during the manufacturing stages, thus prompting the production of foods with improved nutritional properties.

Concerning pre-milling or pre-processing procedures, debranning was investigated among different studies for the production of durum wheat ingredients and/or pasta with higher amounts of health-relevant components and structural features giving good sensory properties [ 119 , 120 , 121 ]. Indeed, by gradually removing the kernel layers through an abrasive scouring, debranning has been shown to:

• - Increase semolina yield and quality;
• - Reduce the ash content;
• - Reduce the contamination by mycotoxins, agrochemicals, and heavy metals.

In that way, it provides the possibility of collecting fractions with selected content of bioactive compounds, which can be used as supplements for the formulation of functional foods [ 206 ]. About this, Martini et al. 2015 [ 120 ] applied a twelve-step sequential debranning process to durum wheat and monitored the content of phenolic acids and total antioxidant capacity in both the bran fractions and the debranned kernels. From the results of their study, it can be inferred that: (i) total phenolic acids content was much higher in the bran fractions than in debranned kernels in all samples collected during the debranning, confirming that these compounds are mainly accumulated in the external layers; (ii) the different phenolic acids forms showed different occurrence among the bran fractions, suggesting the possibility to find the optimum debranning level needed to produce fractions, and debranned kernels with the highest contents (iii) the total antioxidant capacity assessed in the bran fractions and debranned kernels were higher than displayed by wholemeal, semolina and coarse bran, produced from the same durum wheat employed in the study by traditional milling. Therefore, the debranning process was proposed as a valuable approach for obtaining: bran fractions, which can be added to the formulations of wheat-based foods with enhanced nutritional and health value, and debranned kernels to be entirely milled for the production of less refined and safer products.

Similar conclusions were also reported by Ficco et al. 2020 [ 119 ], whose study investigated the application of the debranning process to purple durum wheat to identify the exact conditions at which such technology provides the flours with the best characteristics, that is to say, higher contents in bioactive compounds, and essential minerals, and lowered amounts of toxic trace elements, such as Pb, Cd, Hg, As, Sn, Ni, Sr, V, and Cr. In their study, purple durum wheat genotypes were chosen for their richness in anthocyanin pigments and antioxidant properties [ 207 ], and six debranning times were applied (from 30 to 180 s). The latter generated six corresponding debranned grains (DG-1 to DG-6): of these, DG-1 and DG-2 seem to provide the optimal trade-offs by containing high levels of antioxidant compounds and essential elements (90% and 89.5%, respectively) and reduced amounts of the toxic elements (loss of 11% and 24.5%, respectively).

Furthermore, Ciccoritti et al. 2017 [ 121 ] integrated the results of Martini et al. 2015 [ 120 ] by exploring the use of debranning products for pasta production and checking the content of nutrients, bioactive compounds, and antioxidant activity throughout the entire process. Specifically, the two pasta samples, one produced with bran fractions-enriched semolina (BF pasta) or the other with micronised debranned kernels (DK pasta), displayed significantly higher content of phenolic compounds and dietary fibre than the control pasta (made with traditional semolina). Moreover, minimal effects on sensory properties were noticed by the authors.

Micronization , as mentioned previously, is another unconventional procedure. It entails an ultra-fine grinding procedure that reduces the particle size of matrices, including bran fractions and kernels, enhancing the bioaccessibility of various compounds, including phenolic acids, the solubility of dietary fibre, and the bioavailability of digestible carbohydrates [ 124 ]. With regard to this point, when Martini et al. 2018 [ 97 ] compared pasta produced with semolina and pasta obtained with micronised kernels, they discovered that the conventional method had a detrimental impact on both the overall antioxidant capacity and the concentration of phenolic acids, particularly during the milling process, as it is related with the removal of the outer layers of the kernels. In contrast, the authors were able to produce whole-wheat pasta that retained the number of antioxidant components even when cooked, thanks to the micronisation process.

Finally, Ciccoritti et al. 2019 [ 123 ] proposed a pre-milling mild debranning, followed by micronisation and air classification to produce high-value fractions to be added to traditional semolina for the manufacturing of naturally enriched pasta. Air-classification was adopted to transport the micronised samples towards a series of ascending airflows which separated heavier gross and fine particles, allowing their collection. This novel technological process permitted to produce of enriched pasta that increased up to 53% in soluble polyphenols, 121% in alkylresorcinols, 64% in arabinoxylans, 113% in dietary fibre, and 20% in resistant starch. In addition, the pasta showed good cooking quality and appreciable sensory features.

Concerning traditional primary processing, milling is a complex procedure of progressive grinding and sieving aimed at breakup wheat kernels and separating the endosperm from the bran, preserving grain quality. As the outer parts of the kernel, especially the bran, the aleurone layer, and the germ, are richer in bioactive compounds and minerals when compared with the starchy endosperm, conventional milling reduces their content in semolina and concentrates them in the milling by-products [ 125 ]. However, lipid peroxidation and rancidity process are known to occur in stored wholewheat flour and negatively affect its quality, shelf-life, and end-use.

The effect of milling on durum wheat on starch, dietary fibre, mineral elements, phenolics, and antioxidant activity was assessed within diverse studies among those reviewed [ 117 , 125 , 126 , 127 ]. This information was crucial to evaluate the significance of nutrient and micronutrient losses as a consequence of conventional milling and to provide a basic understanding to establish, for instance, whether fortification is necessary, which element should be supplemented (in a bioaccessible form), and at what levels [ 125 ].

For instance, Di Benedetto et al. 2013 [ 126 ] found that the milling process determined a negative effect on ABTS·+ [2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] scavenging activity of semolina and pasta compared with the whole meal, for both hydrophilic and lipophilic extracts. This result may be attributed to the removal of the outside layers of the kernel, including the pericarp, a part of the aleurone layer, and germ, which is richer in functional components, and responsible for antioxidant activity.

Similarly, Di Silvestro 2014 [ 117 ] evaluated the effects of two milling systems (water and stone) differing in the temperature generated during grinding (namely, 30 and 60 °C) and of storage conditions on the concentration of phytochemicals. By comparing the milling techniques, the stoneground wheat grains (60 °C) showed the highest amylose and resistant starch amounts, which could be advantageous for lowering the glycaemic index of the final products. In contrast, the polyphenol content was significantly reduced in the analysis of flour samples produced using the stone mill compared with the water mill.

Cubadda et al. 2009 [ 125 ] focused their research on the effect of processing on the contents of eight minerals—i.e., calcium, copper, iron, magnesium, phosphorous, potassium, selenium, and zinc. Their results showed that conventional roller milling significantly reduced the content of each mineral in durum wheat grains. Specifically, the concentration losses widely changed based on the element, according to the following retention order: Se > Ca > Cu > P ≈ K > Fe > Mg ≈ Zn, from 16 % for Se to 66% for Zn. In addition, calcium increased after cooking, whereas the concentrations of the other minerals were either unchanged or slightly reduced.

Some studies, among those reviewed, instead focused on the storage conditions of both grains and semolina before the pasta-making process. Indeed, the quality of grains and semolina need to be preserved and maintained through appropriate temperature and moisture conditions, as well as protective treatments, respectively, before and after milling. During storage, indeed, the grain quality can be deteriorated because of both abiotic and biotic factors, and prolonged storage can cause adverse effects on processing and end-product features.

Variations in abiotic factors, such as the duration of the storage, the temperature, and the moisture of grain and semolina, caused changes in thiol (SH), lipids, carotenoids, and phenols contents, with effects on the technological and nutritional properties [ 116 , 117 , 118 , 208 ]. For instance, according to Tomić et al. 2013 [ 116 ], the amount of free sulphydryl groups increased during postharvest wheat and flour maturation, as well as with the increase in temperature and gluten incubation time. However, the most unstable components, especially in whole-wheat flours, are the lipids that are subjected to enzymatic degradation reactions, leading to a reduction in functionality, palatability, and nutritional properties [ 209 ]. Concerning carotenoids, Mellado-Ortega et al. 2015 [ 118 ] found that under long-term storage conditions, the total carotenoid content decrease according to a temperature-dependent first-order degradative kinetic model. Moreover, according to Di Silvestro 2014 [ 117 ], after 6-month storage of flour at a temperature ranging from 20 to 25 °C, a decrease in soluble dietary fibre and bound polyphenols was observed, whilst other wheat grain components, such as starch, remained unvaried.

Regarding biotic factors, instead, pests consisting of insects and mites need to be controlled at various stages such as on-farm storage, bulk storage, and during transport [ 210 ]. Fumigants are especially used to control pests and insects in food commodities to reduce product losses. However, such chemicals are also associated with serious risks such as ozone depletion, insect resistance, and residues on the grain surface, and therefore alternatives are constantly searched [ 210 ]. Regarding these aspects, Hwaidi et al. 2016 [ 114 ] assessed the effect of fumigation of grain and commercial semolina with sulfuryl fluoride (SF) under different conditions on grain germination and the technological quality of the grain, semolina, and pasta quality. SF appreciably reduced the germination percentage of fumigated durum wheat, with increasing impact under higher fumigant concentration, whilst it had little to no effect on grain test weight, thousand kernels weight, hardness, protein content, semolina ash content, and mixograph properties. At the highest SF concentration (31.25 mg/L for 48 h), there was a tendency for pasta cooking loss to be increased but still acceptable, and other pasta properties were largely unaffected.

Another study, instead, focused on the effects of gaseous ozone treatments on DON, microbial contaminants, and technological features of wheat and semolina [ 115 ]. Ozone is a powerful disinfectant, which readily degrades specific contaminants, including several mycotoxins, and is a promising fumigant against insects and a wide range of microorganisms that can survive and grow in the grains during storage [ 211 ]. However, due to its oxidant-reduction potential, ozone can react with many functional groups present in lipids, proteins, and carbohydrates, affecting rheological properties and technological acceptance of flours and doughs [ 115 ]. Specifically, results from Piemontese et al. 2018 [ 115 ] reported the efficacy of gaseous ozone treatments in reducing DON, DON-3-Glc, bacteria, fungi, and yeasts in naturally contaminated durum wheat and allowed to identify the optimal conditions, which do not affect chemical and rheological properties of durum wheat, semolina, and pasta (55 g O 3 h −1 for 6 h).

Within the secondary processing, the pasta production process involves mixing and kneading , extrusion, and drying to reach about 12.5% of moisture and then cooking . For “fresh pasta”, it should be underscored, however, that drying is replaced with pasteurisation with the aim of stabilising the previously extruded product.

To date, the most important technological advances in pasta processing concerned:

• - The adoption of different types of mixers, mixing speeds, times, and pressures;
• - The introduction of die inserts lined with Teflon, partially replacing bronze ones;
• - The increase in drying temperatures from 75 °C to 100 °C and even above, thus reducing the drying time from the original 48 h to only 2–3 h [ 143 ].

However, the pasta manufacturing process can be thought of as “mature technology” due to its wide-reaching diffusion and the few innovations applied to this process in the last years [ 212 ].

The initial step of the pasta manufacturing process consists of mixing semolina and water: mixing times, speeds, and pressures; hydration level; and water temperature vary based on the processing conditions, the moisture content, the particle size of semolina, and the final pasta shape. In particular, mixing and kneading under vacuum conditions have been recently designed for pasta and noodle manufacturing applications, as it allows for the following:

• - Uniforming the hydration process and creating a more homogenous water–flour mixture;
• - Avoiding the incorporation of oxygen, thus eliminating air bubbles in the final products and limiting enzymatic activity responsible for the antioxidant degradation [ 140 , 213 , 214 , 215 , 216 ].

In this context, several studies such as Hidalgo and Brandolini 2010 [ 128 ], Hidalgo et al. 2010 [ 130 ], and Fratianni et al. 2012 [ 140 ], as reviewed in this paper, investigated the effects of processing stages on tocol and carotenoid contents of different wheat-based products and confirmed that for pasta the degradation of such antioxidants is mostly limited to the mixing and kneading steps. In addition, the flour particle size, depending on the genotype, the grain hardness, and the milling procedure, is another possible source of colour variation [ 141 ].

Hidalgo et al. 2010 [ 130 ] pointed out that the kneading led to a higher total carotenoids degradation in pasta compared with bread and biscuits due to the longer time of the phase (7 vs. 3 min) and found significant differences in the percentage of degradation based on the wheat species used for the pasta formulation (54% in bread wheat, 34% in semolina and 15% in einkorn). This was mostly attributed to the fact that the wheat species under study have diverse lipoxygenase activity (bread wheat > durum wheat > einkorn).

Similar findings were obtained for tocols by Hidalgo and Brandolini 2010 [ 128 ], who observed higher losses during the kneading phase (44.2%), and the no-vacuum extrusion step (29.7%). As for Hidalgo et al. 2010 [ 130 ], Hidalgo and Brandolini 2010 [ 128 ] results agreed on identifying einkorn as a better provider of tocols, in the end, products than durum and bread wheat.

In line with them, Hidalgo and Brandolini 2012 [ 129 ] stressed the need to select genotypes with high yellow pigment colour and low enzymatic activity, to maintain higher antioxidant features and a better appearance in the final products. Utilising species/subspecies/accessions differing in their enzymatic activity or their esterification ability could be useful for producing foods with improved technological and nutritional quality features [ 43 , 131 ]. However, other approaches to increase carotenoids and tocols stability were also proposed, such as the enrichment of pasta with encapsulated carrot waste extracts in oil [ 177 ].

Regarding extrusion , bronze dies have been partially replaced by Teflon inserts , especially in high-speed plants, as they are associated with some disadvantages, such as:

• - Faster wear of the die insert;
• - Lower production yield of the press;
• - Lower breaking strength;
• - Higher susceptibility to insect attacks [ 132 , 133 ].

Despite this, bronze inserts give a rough surface to pasta, which better binds the sauce, with greater appreciation by consumers. This is one of the primary motivations for which several pasta companies still prefer to use bronze inserts, along with the valorisation of traditional raw material (for instance, semolina of old varieties and landraces) and the adoption of low drying temperatures. Indeed, such pasta production models tend to appear appealing to a niche of consumers who value authenticity and tradition.

Valuable results about the influence of extrusion on pasta quality feature other than surface characteristics were reported by several studies that were reviewed in this paper, namely Hidalgo and Brandolini 2010 [ 128 ], Hidalgo et al. 2010 [ 130 ], Abecassis et al. 1994 [ 134 ], Debbouz and Doetkott 1996 [ 135 ], Zardetto and Rosa 2009 [ 136 ], and Pagani et al. 1989 [ 137 ].

For instance, Abecassis et al. 1994 [ 134 ] found that an increase in the extrusion temperature (from 35 °C to 70 °C) is able to cause an increase in cooking losses up to 250%. However, the damage due to high extrusion temperature could be mitigated by increasing the level of hydration and the rotation speed of the screw. In this regard, Debbouz and Doetkott 1996 [ 135 ] proposed extrusion temperatures between 45 and 50 °C and hydration levels of 31.5–32% as optimal conditions to reduce pasta cooking losses.

Moreover, attention should be posed to the use of vacuum: as in the case of mixing and kneading, applying vacuum to the extrusion or lamination phases significantly reduced carotenoids and tocols degradation [ 128 , 130 , 136 ]. Additionally, another function of a vacuum for the lamination process could be to give extensibility and consistency similar to those obtained with the extrusion [ 136 ].

Along with mixing and extrusion, the drying process plays a key role in ensuring the quality of pasta since its conditions may cause thermal and mechanical damage, with negative consequences on the texture and the sensory properties of the product [ 35 ]. High-temperature drying (HT) advantages consist of a reduction in microbial contamination and improvement of the cooking quality of pasta, whilst disadvantages concern the occurrence of Maillard-type reactions that leads to protein modifications due to cross-linking with other compounds, which can affect both protein digestibility and antigenicity [ 138 , 143 ]. The extent of the Maillard-type reactions in pasta dried at high temperatures can be especially determined by measuring the furosine level and is significantly related and dependent on the α-amylase activity and the amount of reducing sugars in the semolina [ 139 ].

Within this context, the study by De Zorzi et al. 2007 [ 143 ] was enlightening since it evaluated the effects of different drying temperatures on the digestibility and potential allergenicity of pasta samples cooked in boiling water. Temperatures considered by the study were both in the range of those used by industry (60, 85, and 110 °C), of a traditional room temperature drying (about 20 °C), and an ultra-high temperature treatment (180 °C). This latter temperature, which is rarely used in the production of industrial pasta, was considered to evaluate the effects of very drastic heating. The findings confirmed that protein digestibility is impaired by drying temperatures, and those semolina proteins aggregated with each other during drying, forming strong and stable interactions. Specifically, for the samples treated at temperatures in the range of those by industry, this aggregation was due to the formation of disulfide bonds and hydrophobic interactions, as almost complete solubilisation was observed by using a solvent able to disrupt these interactions. In contrast, this was not possible to be detected on the proteins of the samples dried at 180 °C, which were characterised by the presence of aggregates stabilised by irreversible interactions. Moreover, IgE-immunoblotting and IgE dot blotting were carried out using the sera of patients with food allergies to wheat in order to detect the potential allergens coming from the cooked pasta samples before and after digestion. The latter analysis revealed that, regardless of the degree of heat treatment, the digesting process was unable to entirely eliminate the presence of IgE-reactive peptides, even if it was adequate to break down the proteins in the samples dried up to 110 °C.

Besides protein digestibility, another aspect to be evaluated is the effect of drying temperatures and cooking on starch digestibility, as its degradation is affected by both the physical modifications (mainly gelatinisation of starch) and the compact protein matrix surrounding its granules. The changes in starch structure during pasta manufacture can be tailored to produce slowly digestible starch for pasta with a reduced glycemic index.

According to Petitot et al. 2009 [ 145 ] and Petitot and Micard 2010 [ 146 ], changes in dried and cooked pasta structure due to the drying process were moderate up to 70 °C and increased at higher temperatures, especially for very high temperatures (90 °C) applied at the end of the drying profile. In fact, the latter drying process resulted in a 10% reduction in protein digestibility and induced a lower starch digestibility in cooked pasta.

Finally, Stuknytė et al. 2014 [ 144 ] adopted a new static protocol for in vitro digestion [ 217 ] that allows assessing the digestibility of cooked spaghetti dried under low temperature (LT) or HT conditions by measuring the release of amino acids and sugars in the digestates. Following their results, intense starch degradation was observed at the intestinal level, as demonstrated by the release of 12.6 and 15.9 g 100 g −1 of sugars in the digestates of LT and HT-cooked spaghetti, respectively.

Therefore, contrary to Petitot et al. 2009 [ 145 ], Stuknytė et al. 2014 [ 144 ] stated that HT drying does not decrease the in vitro digestibility of starch, despite the slightly firmer protein network. Instead, in the same samples, diverse amounts (16.3 and 12.5 g 100 g −1 protein) of free amino acids were found, thus indicating that the HT sample was slower to digest.

3.4. Pasta Formulation Factors

Care is recommended to be taken to produce very high-quality pasta, starting with the choice of the raw materials, ingredients, and additions, moving on to the processing line parameters, and finishing with the packaging requirements [ 218 ].

Recent advancements in the pasta sector, in particular, were mainly focused on ways to improve the nutritional value of the product and to provide potential health advantages to consumers through the use of unconventional ingredients [ 218 , 219 ]. Among the latter, this paper’s team of authors identified and classified the papers dealing with changes in pasta formulation based on the ingredient added, as follows:

• High-fibre ingredients (beta-glucans, inulin, resistant starch, bran fractions);
• High-protein ingredients (protein concentrates, legume flours, insects);
• Probiotics ( Bacillus coagulans GBI-30);
• Other highly nutritious and functional ingredients.

For the first class ( high fibre ingredients ), the literature demonstrated that adding dietary fibre to pasta, particularly its soluble fraction, causes a decrease in the glycaemic index of the products [ 149 ]. In addition, high-fibre grain products are also usually rich in minerals, vitamins, and biologically active compounds, all of which offer additional health advantages [ 149 ]. However, due to the presence of bran, whole-grain foods generally have inferior technological and sensory properties than refined ones [ 121 ]. For instance, according to Padalino et al. 2015 [ 220 ], wholemeal spaghetti samples showed an improvement in the chemical composition by preserving high protein and insoluble dietary fibre contents, but they had worse cooking quality features, as demonstrated by high cooking loss, low elasticity, firmness, and colour, compared with the semolina spaghetti.

To overcome these drawbacks typical of wholemeal products, Sobota et al. [ 111 ] suggested using a common wheat bran additive of up to 30% and favoring wheat bran with fine and uniform granulation and possibly high content of gluten.

With regard to granulation, Alzuwaid et al. 2020 [ 147 ] examined the impact of the incorporation at different levels of several bran fractions with diverse particle sizes on the technological and health-promoting properties of pasta. Their findings showed that higher levels of bran incorporation (especially at 20%) decreased pasta quality, but authors highlighted that such negative impact could be reduced using finer bran. Moreover, the study found that the increase in antioxidants (by up to 65%), ferulic acid (up to 400%), and phytosterols (up to 130%) due to the incorporation of bran was insensitive to the particle size above 10% incorporation. Thus, it was recommended to make use of finer fractions, especially when the bran is added to pasta at a 20% level, since they can provide good quality performances as well as higher phytochemical contents.

From a sensory quality point of view, also the results from Steglich et al. 2015 [ 148 ] stressed that consumers tend to like pasta more when a decreasing particle size of semolina is used in its formulation, probably because of the smoother pasta surface and milder whole wheat aroma.

Similar ingredients are represented by resistant starch, inulin, β-glucans , as well as non-conventional flours such as psyllium, oat, and sorghum flours.

Specifically, Aribas et al. 2020 [ 152 ] reported significant advantages of the supplementation of pasta with resistant starch type 4 (RS4) compared with bran supplementation. Pasta formulated with such ingredients had a better look, texture, and sensory qualities, reduced cooking loss, higher firmness, higher total dietary fibre, improved mineral bioavailability, and lower in vitro glycaemic index than pasta supplemented with wheat bran.

Chillo et al. 2011 [ 153 ] instead investigated the in vitro glycaemic impact and cooking quality of spaghetti made with semolina enriched with one of either two types of β-glucan barley concentrates , namely Glucagel ®® (GG) and Barley Balance™ (BB). The addition of up to 10 g/100 g of both types of β-glucan did not significantly alter the pasta cooking quality compared with the control and improved the fibre-associated nutritive properties of the spaghetti. Moreover, BB showed a better capacity to lower the glycaemic index of the pasta compared with GG.

Moreover, inulin is acknowledged as an ingredient that promotes health through several mechanisms, dealing with counteracting constipation, supporting the growth of microflora in the digestive tract, and managing blood sugar levels. Therefore, because the interactions between starch and inulin could further slow starch digestion and thus lower the glycaemic response, its addition to pasta was proposed to obtain a functional food [ 154 ]. In this respect, both Garbetta et al. 2020 [ 154 ] and Padalino et al. 2017 [ 155 ] focused on the effects of the addition of inulin with different polymerisation degrees on the chemical and sensory properties of spaghetti based on whole-meal durum wheat semolina. In particular, Garbetta et al. 2020 [ 154 ] provided specific data on how the polymerisation degree affected sensory quality, whilst it did not influence the glycaemic index values. Moreover, their results demonstrated that, for all the cultivars under study, the pasta sample produced with the cardoon roots inulin released a statistically larger amount of inulin in the digestive tract than the one produced with chicory, thus underscoring its importance prebiotic. In particular, Garbetta et al. 2020 [ 154 ] evidenced that the polymerisation degree affected most of the sensorial attributes of pasta, whilst it did not influence the glycaemic index values. Moreover, the results showed that for all the studied cultivars, the pasta sample produced with the high polymerisation-degree inulin (cardoon roots) released a statistically higher amount of inulin in the digestive tract than the one produced with the low polymerisation-degree inulin (chicory), thus highlighting its importance prebiotic function.

Padalino et al. 2017 [ 155 ] agreed with this by stating that the addition of cardoon roots inulin to the dough provided better results and suggested the selection of inulin with a high polymerisation degree for pasta enrichment.

Other studies regarded the addition of other types of flours, such as psyllium, oat, and sorghum flours , since they are naturally rich in dietary fibre [ 151 , 156 ]. A positive effect of the addition of different types of dietary fibre in pasta on in vitro digestion was well documented [ 151 , 156 ]. Therefore, at this stage, it would be interesting to have confirmation from in vivo starch digestion analysis [ 151 ]. Moreover, additional research would be necessary to evaluate the acceptance of enriched pasta from consumers [ 151 ].

Incorporating high-protein ingredients into pasta is thought to be crucial for increasing the protein content, which is typically around 15%, and making up for durum wheat’s comparatively low quantities of the key amino acid lysine. Pasta with a higher protein content typically has better resistance to overcooking, high firmness, low stickiness, and low cooking loss [ 161 ]. Additionally, as protein content rises, starch digestion becomes less extensive due to a larger, more cohesive network that restricts access to amylase and lessens starch gelatinisation [ 161 ]. In terms of protein quality, instead, raising the dough strength of durum wheat by increasing the quantity of glutenin and the ratio of HMW-GS/LMW-GS did not guarantee an increase in pasta firmness [ 187 ].

Alzuwaid et al. 2021 [ 157 ] investigated if bran protein concentrate could be added to spaghetti to improve its nutritional value without impairing its quality. Compared with durum-semolina spaghetti, the wheat bran protein concentrate boosted the total quantity of essential amino acids and raised the protein level by 90%. Additionally, the overall quality of the spaghetti was comparable to the control (100% durum wheat semolina) up to 5–10% levels of incorporation but began to degrade at 20%, even though it was still superior to commercial wholemeal spaghetti made with bran addition in terms of cooking loss and appearance. Therefore, according to Alzuwaid et al. 2021 [ 157 ], such a low-value waste stream could be a promising alternative source of protein and a better way to generate added value for the milling sector.

Recent research has assessed various choices for enhancing durum wheat pasta with high-protein sources other than durum wheat, such as flour from insects and legumes. These options were evaluated in terms of their technological, nutritional, and sensory qualities. For instance, some studies were focused on faba bean enrichment of durum wheat pasta, as faba bean has larger amounts of dietary fibre and proteins, the latter of which are naturally abundant in the essential amino acid lysine [ 159 , 160 , 221 ]. Therefore, a human feeding trial performed by Chan et al. 2019 [ 221 ] showed that substituting durum wheat semolina with 25% faba bean flour, starch isolate, protein isolate, and protein concentrate had positive impacts effects on post-prandial glycemia and satiety. However, despite its ability to improve nutritional value, faba bean addition is linked to changes in the rheological characteristics of pasta. In that regard, Greffeuille et al. 2015 [ 160 ] found that high-temperature drying strengthened the textural properties of 35% legume pasta and induced several benefits, such as a decrease in appetite and improved digestive comfort, besides having no effect on pasta’s low glycemic and insulin indices [ 159 ]. Similarly, another study evaluated the replacement of semolina with lupin flour , and, in this case, it was also found that the protein, dietary fibre, and mineral concentrations were increased [ 162 ]. Additionally, it was tested and recommended to combine lupin flour with RS4 to develop pasta with appropriate cooking quality, sensory qualities, and enhanced nutritional properties [ 162 ].

Crickets and cricket powder , although very different from other ingredients mentioned above, may also be considered valuable protein supplements in the production of wheat-based food products, as they contain considerable amounts of proteins, along with lipids (especially polyunsaturated fatty acids) and minerals [ 158 ]. Depending on the type of insect, its development stage, and the type of breeding, the protein content can considerably vary, from 13% to over 77% of dry matter [ 222 ].

The European legislation considers whole insects and their parts as novel foods (NF) with specific microbiological, chemical, and environmental risks to be monitored [ 223 , 224 , 225 , 226 ], whilst other countries do not yet have regulations regarding edible insects. Recently, the European Food Safety Authority (EFSA) Panel on Nutrition, Novel Food, and Food Allergens identified no other safety concerns than allergenicity for A. domesticus (AD) formulations and concluded that this novel food is safe under the proposed uses and use levels. The latter change depending on the formulations (frozen, dried, powder) and the food categories in which the ingredient is expected to be added (e.g., for dried pasta, the maximum use levels are 1 g NF/100 g and 3 g NF/100 g of AD dried and AD powder, and AD frozen, respectively) [ 224 ].

In Duda et al. 2019 [ 158 ], three levels of durum semolina replacement (5%, 10%, and 15%) with cricket powder were tested to examine the associated effects on the nutritional content, cooking and textural qualities, and colour, as well as consumer acceptance of the enriched pasta. According to the results, the quality traits of the enriched pasta significantly differed compared with those of the control pasta. In particular, the following aspects have been noted: a significant increase in the content of protein, lipids, and minerals; different cooking properties, such as a reduction in cooking weight and cooking loss, increased optimal cooking time, and higher firmness, and a general product’s colour shifting towards red and blue. Moreover, consumers involved in the sensory analysis accepted enriched pasta quite well.

Only two studies among those reviewed were found to deal with probiotic pasta [ 163 , 164 ]. This was expected since heat-treated foodstuffs, such as dry pasta, are not usually utilised as a probiotic carrier, as their processing includes a number of heat treatments to which most of the microorganisms cannot survive. Despite this, both Fares et al. 2015 [ 163 ] and Konuray and Erginkaya 2020 [ 164 ] concentrated their research on spore-forming probiotic microorganisms that have lately gained interest in the cereal industry for their ability to maintain their viability in heat-treated operations, such as boiling and baking. Both studies specifically analysed the inclusion in pasta formulation of the B. coagulans GBI-30 strain, which obtained the Generally Recognised As Safe (GRAS) status in 2012 from the U.S. Food and Drug Administration (FDA), following an assessment of toxicological studies [ 227 ].

Following Fares et al. 2015 [ 163 ], the probiotic strain remained viable during the pasta manufacturing and boiling processes, and its concentration in cooked samples (about 9.0 log CFU/100 g) would be considered sufficient to exert beneficial effects on the consumer. In line with this, Konuray and Erginkaya 2020 [ 164 ] analysed the probiotic pasta made with B. coagulans GBI-30 spores to establish its microbiological characteristics and quality parameters at 0 and 6 months of storage. Interestingly, the B. coagulans GBI-30 count was above 6 log CFU/g even after the pasta had been stored at room temperature for six months and cooked for eight minutes at 100 °C.

With regard to the last class (other highly nutritious and functional ingredients) , it was defined in that general way by this team of authors because most of the innovative ingredients considered by such reviewed studies were characterised by multiple different nutritional and functional properties. Accordingly, researchers have developed pasta with various bioactive ingredients, such as:

• - Moringa oleifera pod powder [ 168 ];
• - Purslane [ 172 ];
• - Soy okara [ 167 ];
• - Stinging nettle [ 169 ];
• - Fermented quinoa flour [ 170 ];
• - Potato and pigeonpea flour [ 178 ].
• - Carrob flour [ 176 ]
• - Mushroom powder [ 171 , 180 ];
• - Brewers spent grain [ 173 , 174 ];
• - Carrot waste encapsulates [ 177 ];
• - Olive pomace [ 179 ];
• - Fish raw material [ 165 ];
• - Micro and macroalgae [ 166 , 175 , 181 , 182 , 183 , 184 ].

Research on the above-listed ingredients was carried out by the related authors’ teams with the aim of finding the trade-offs between nutritional improvement and satisfactory sensorial properties of pasta. Those end up confirming durum wheat semolina pasta as an optimal carrier for non-conventional ingredients. This review’s authors pointed out that the addition of ingredients to durum wheat semolina experimented in the studies, although in different proportions (mostly, up to 20% level of replacement), always caused changes in dough, which had various effects on the sensory properties of the product. However, the ingredients were an important source of nutrients, including dietary fibre, minerals, vitamins, phenols, and other bioactive compounds exerting a beneficial impact on human health, for example, phenols.

As a result, the enrichment of pasta products was proven in all of the reviewed studies to be a good strategy for the development of higher-quality pasta, enabling the achievement of both food safety principles, high nutritious values, functionality, and also satisfactory consumer acceptance.

Moreover, some ingredients, such as those obtained from agro-industrial by-products, or those not already consumed to any significant degree, could match the growing request of both the food industry and consumers for more sustainable processes by also providing environmental and economic benefits. For instance, valorising agro-industrial by-products as ingredients for pasta enrichment runs in the direction of circular economy as it allows for minimising waste and generates economic advantages for the agri-food chains involved. Similarly, novel foods such as insects and algae, when added without exceeding the recognised levels for safe ingestion and accordingly to the regulation restrictions (specific for species and food categories) [ 225 ], could represent a viable approach to provide pasta with non-meat based proteins of high biological value, along with balanced fatty acid profiles, vitamins, antioxidants, and minerals.

4. Conclusions

The authors of the present systematic literature review comprehensively discussed the factors affecting durum wheat quality within the pasta sector, including genotype, cropping, technological, and pasta formulation ones. Effects on nutritional, technological, and health properties of durum wheat grain, semolina, and pasta were explained, along with the improvement options.

Durum-wheat grain composition, which includes macronutrients (proteins, polysaccharides, and lipids), micronutrients (minerals, vitamins), and health components, serves as the starting point for any quality assessment (phytochemicals). The effects of the genotype and growing conditions for the determination of the content and composition of such compounds are of comparable significance, with some traits being more influenced by genotype and others from the environment. Among the others, the bioactive compounds are synthesised by plants as part of their defense mechanism against abiotic and biotic stresses, and their accumulation often increases in response to environmental constraints and the related agronomic management adopted.

Moreover, quality needs to be maintained along the processing steps for the production of semolina and pasta: in that sense, previous research has been quite clear and straightforward in defining which operations should be carefully controlled to obtain high-quality final products (e.g., drying), and which are the novel techniques (e.g., debranning, micronisation) that can contribute to the improvement of quality attributes.

With regard to new pasta formulations, instead, in the last few years, there has been an exponential growth of studies on the addition of alternative ingredients to semolina to produce fortified pasta with enhanced nutritional and functional properties. However, further research on nutrient bioavailability and stability and in vivo antioxidant capacity of these new pasta formulations are needed to successfully design, produce, and include these innovative products in future food habits development.

Accordingly, the review allowed this team of authors to identify a number of promising strategies for improving durum wheat quality from farm to fork, including:

• Exploring landraces’ germplasm as a source of novel alleles to improve productivity, environmental adaptability, tolerance or resistance to biotic stresses, and nutritional and health value;
• Making durum wheat nutritional and health-promoting properties the new goals of durum wheat breeding programs;
• Promoting participatory and decentralised breeding programs to select the desired genotypes also in relation to the choice of the most suitable growing area;
• Supporting low input practices, including organic farming, such as conservation tillage, crop rotation, and intercropping, to reduce environmental impact, achieve ecosystem services and improve grain quality attributes;
• Optimising N fertilisation strategies in terms of rate and time to maintain grain technological quality whilst reducing the release of N into the environment;
• Adopting innovative techniques, such as debranning, air classification, and micronisation, to increase the nutritional and health value of products in the pasta sector;
• Experimenting with new pasta formulations containing plant-based ingredients in order to contribute to the diversification of healthier and more nutritious diets;
• Evaluating environmental, nutritional, and health benefits and/or risks associated with new formulations of pasta through holistic and standardised methodologies (e.g., nutritional Life Cycle Assessment), as suggested and carried out in the previously published specialised literature [ 228 , 229 , 230 , 231 ].

Thus, the authors concluded that now more than ever, multidisciplinary approaches involving agronomists, breeders, ecologists, food technologists, and economists will be critical for planning more sustainable and high-quality durum wheat production systems [ 232 , 233 ].

Acknowledgments

This study was carried out as a part of the Ph.D. Course on “Agricultural, Food and Environment Science” of the University of Catania that Silvia Zingale is currently attending with a research project entitled “Addressing quality and sustainability in the organic durum wheat ( Triticum turgidum subsp. durum (Desf.) Husnot) supply chain”.

Funding Statement

This research received no external funding.

Author Contributions

Conceptualisation, S.Z., P.G., C.I., A.S. and U.A.; methodology, S.Z., P.G. and C.I.; writing—original draft preparation, S.Z.; writing—review and editing, B.F. and G.T.; supervision P.G., C.I., A.S. and U.A. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

Conflicts of interest.

The authors declare no conflict of interest.

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

• DOI: 10.1007/978-3-030-34163-3_1
• Corpus ID: 216461971

The Importance of Wheat

• G. Igrejas , G. Branlard
• Published 2020
• Agricultural and Food Sciences, History

44 Citations

Adaptability of wheat genotypes under multi-environment trials for northern hills zone, mining of leaf rust resistance genes content in egyptian bread wheat collection, acceptance and utilization efficiency of a purple durum wheat genotype by sitophilus granarius (l.), breeding for silicon-use efficiency, protein content and drought tolerance in bread wheat (triticum aestivum l.): a review, genomic insights of a native bacterial consortium for wheat production sustainability, microsatellite markers-aided dissection of iron, zinc and cadmium accumulation potential in triticum aestivum, synergistic effect of zno nps and salicylic acid on carbohydrate and protein of wheat plant (triticum aestivum l.).

• Highly Influenced

Zinc-solubilizing Bacillus spp. in conjunction with chemical fertilizers enhance growth, yield, nutrient content, and zinc biofortification in wheat crop

The effect of climate conditions on the phenological features of the autumn oat crop, impact of silicate fertilizer on soil properties and yield of bread wheat in nitisols of tropical environment, 16 references, the contribution of wheat to human diet and health, wheat: production, properties and quality, cimmyt series on carbohydrates, wheat, grains, and health: wheat-based foods: their global and regional importance in the food supply, nutrition, and health1,2, developing new types of wheat with enhanced health benefits, what is gluten, wheat arabinoxylans : exploiting variation in amount and composition to develop enhanced varieties, wheat gluten polymer structures : the impact of genotype environment and processing on their functionality in various applications, the neolithic southwest asian founder crops, non-celiac gluten sensitivity: all wheat attack is not celiac, related papers.

Showing 1 through 3 of 0 Related Papers

The Economics of Wheat

Research challenges from field to fork

• Conference paper
• Cite this conference paper

• J. Dixon 4  

Part of the book series: Developments in Plant Breeding ((DIPB,volume 12))

3218 Accesses

4 Citations

1 Altmetric

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Subscribe and save.

• Get 10 units per month
• Download Article/Chapter or eBook
• 1 Unit = 1 Article or 1 Chapter
• Cancel anytime
• Available as PDF
• Read on any device
• Instant download
• Own it forever
• Compact, lightweight edition
• Dispatched in 3 to 5 business days
• Free shipping worldwide - see info
• Durable hardcover edition

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Unable to display preview.  Download preview PDF.

Aksoy MA, Beghin MC (2003) Global Agricultural Trade and Developing Countries. World Bank, Washington

Google Scholar  

Alston JM, Norton GW, Pardey PG (1995) Science under Scarcity: principles and Practice for Agricultural Research Evaluation and Priority Setting. Cornell University Press in cooperation with the International Service for National Agricultural Research, Ithaca and London

Alston JM, Marra MC, Pardey PG, Wyatt TJ (2000) A meta analysis of rates of return to agricultural R&D: Ex pede Herculem? Research Report, vol 113. IFPRI, Washington, DC

Bell MA, Fischer RA, Byerlee D, Sayre K (1995) Genetic and agronomic contributions to yield gains: a case study for wheat. Field Crops Res 44:55–56

Article   Google Scholar  

Byerlee D (1994) Modern Varieties, Productivity, and Sustainability: Recent Experience and Emerging Challenges. CIMMYT, Mexico, DF

Byerlee D, Moya P (1993) Impacts of International Wheat Breeding Research in the Developing World 1969–1990..: CIMMYT, Mexico, DF

Byerlee D, Traxler G (1995) National and international wheat improvement research in the post Green Revolution period: Evolution and impacts. Am J Agr Econ 77(2):268–78

Chand R (2005) The Rice-Wheat farming System, Punjab, India. Draft manuscript. FAO, Rome

CIMMYT (2004) Global Trends Influencing CIMMYT’s Future. Prepared by the Global Trends Task Force in Support of Strategic Planning at CIMMYT. CIMMYT, Mexico, DF

Cooksey LJ, Arellano E (2006) CIMMYT Training: Activities & Impact. CIMMYT, Mexico, DF

Dixon J (2003a) Economics of Conservation Agriculture: farm profitability, risks and secondary benefits from the farmers’ perspective, Keynote paper, Second World Congress of Conservation Agriculture (August 2003), Foz de Iguacu, Brazil

Dixon J (2003b) Targeting Agricultural Services to Different Farming Systems for Sustainable Agriculture and Rural Development in Iran, National Agricultural Development Workshop (December 2003), Tehran, Iran

Dixon J, Gulliver A, with Gibbon D (2001) Farming systems and poverty. Improving farmers’ livelihoods in a changing world. FAO/World Bank, Rome/Washington DC

Evenson RE, Gollin D (2003a) Assessing the impact of the Green Revolution: 1960 to 2000. Science 300:758–761

Article   CAS   Google Scholar  

Evenson RE, Gollin D (eds) (2003b) Crop Variety Improvement and Its Effect on Productivity: The impact of international agricultural research. CABI, Wallingford

Falcon W, Naylor RL (2005). Rethinking Food Security for the 21st Century. Am J Agr Econ 87(5): 113–1127

FAO (2003) World Agriculture to 2015/2030: an FAO perspective. FAO and Earthscan, Rome, Italy

FAO (2006) http://faostat.fao.org/faostat/accessed June, 2006

Heisey PW, Lantican M, Dubin HJ (2002) Impacts of international wheat breeding research in developing countries, 1967–97. CIMMYT, Mexico, DF, pp 3–14

Hodson DP, Singh RP, Dixon JM (2005) An initial assessment of the potential impact of stem rust (race UG99) on wheat producing regions of Africa and Asia using GIS. Poster presentation, 7th International Wheat Conference, Nov 27–Dec. 2, 2005, Mar del Plata, Argentina, p 142

Lantican MA, Pingali PL, Rajaram S (2002) Are marginal wheat environments catching up? In: Ekboir J (ed) CIMMYT 2000–2001 World Wheat Overview and Outlook: Developing No-Till Packages for Small Scale Farmers. CIMMYT, Mexico, DF, pp 39–44

Lantican MA, Dubin MJ, Morris ML (2005) Impacts of International Wheat Breeding Research in the Developing World, 1988–2002. CIMMYT, Mexico, DF

Laxmi V, Erenstein O, Gupta RK (2005) Assessing the impact of NRM research: The case of zero tillage in India’s rice-wheat systems. SPIA NRM Case Study presentation to CGIAR AGM (December 2005), Marrakech, Morocco

La Rovere R, Hodson D, He Z, Mezzalama M, Ban T, Payne T, Trethowan R, Crouch J, Lewis J, Sayre K, Braun H-J, Nicol J, Capettini F, Smale M, Dixon J (2006) Early warning on scab epidemics: A scoping study. Draft research Report: CIMMYT

Lee DR (2005) Agricultural Sustainability and Technology Adoption: Issues and Policies for Developing Countries. Am J Agr Econ 87(5):1325–1334

Marasas CN, Smale M, Singh RP (2004) The economic impact in developing countries of leaf rust resistance breeding in CIMMYT-related spring bread wheat. Economics Program Paper 04–01. CIMMYT, Mexico, DF

Maredia MK, Byerlee D (eds) (1999) The Global Wheat Improvement System: Prospects for Enhancing Efficiency in the Presence of Spillovers. Research Report 5. CIMMYT, Mexico, DF

Ortiz-Monasterio JI, Sayre KD, Rajaram S, McMahon M (1997) Genetic progress in wheat yield and nitrogen use efficiency under four nitrogen rates. Crop Sci 37:898–904

Pingali PL (ed) (1999) CIMMYT 1998–99. World Wheat Facts and Trends. Global Wheat Research in a Changing World. Challenges and Achievements. CIMMYT, Mexico, DF

Pingali P, Raney T (2005) From the Green Revolution to the Gene Revolution: How Will the Poor Fare? ESA Working Paper 05–09, Agricultural and Development Economics Division, FAO, Rome, Italy

Reardon T, Berdegue JA (2002) The Rapid Rise of Supermarkets in Latin America: Challenges and Opportunities for Development. Development Policy Review 20(4):371–388

Reynolds MP, Borlaug NE (2006a) Impacts of breeding on international collaborative wheat improvement. J Agr Sci 144: 3–17

Reynolds MP, Borlaug NE (2006b) Applying innovations and new technologies for international collaborative wheat improvement. J Agr Sci 144:95–100

Runge CF, Senauer B, Pardey PG, Rosegrant MW (2003) Ending Hunger in Our Lifetime: Food Security and Globalization. John Hopkins University Press, Washington

Ryan J (2005) International Public Goods and the CGIAR Niche in the R for D Continuum: Operationalising Concepts. Discussion paper, CGIAR Annual General Meeting, Morocco

Sayre KD, Hobbs PR (2004) The raised bed system of cultivation for irrigated production conditions. In: Lal R, Hobbs PR, Uphoff N, Hansen DO (eds) Sustainable Agriculture and the International Rice-Wheat System. Marcel Decker, New York, pp 337–355

Seth A, Fischer K, Anderson J, Jha D (2003) The Rice-Wheat Consortium: An Institutional Innovation in International Agricultural Research on the Rice-Wheat Cropping Systems of the Indo-Gangetic Plains (IGP). New Delhi, The Review Panel Report. RWC

Smale M (1997) The Green Revolution and wheat genetic diversity: some unfounded assumptions. World Dev 25:1257–1269

Smale M, Reynolds MP, Warburton M, Skovmand B, Trethowan R, Singh RP, Ortiz-Monasterio I, Crossa J (2002) Dimensions of diversity in modern spring wheat in developing countries from 1965. Crop Sci 42:1766–79

Trethowan RM, van Ginkel M, Rajaram S (2002) Progress in breeding for yield and adaptation in global drought affected environments. Crop Sci 42:1441–1446

Trethowan RM, Hodson D, Braun H-J, Pfeiffer WH, van Ginkel M (2005) Wheat Breeding Environments. In Lantican MA, Dubin MJ, Morris ML. Impacts of International Wheat Breeding Research in the Developing World, 1988–2002. CIMMYT, Mexico, DF, Chapter 2

Witcombe JR, Gyawalli S, Sunwar S (2005) Participatory Plant Breeding is Better Described as Highly Client-Oriented Plant Breeding. II Optional Farmer Collaboration in the Segregating Generations. Exp Agr 42:79–90

Download references

Author information

Authors and affiliations.

Director, Impacts Targeting and Assessment, International Maize and Wheat, Improvement Center (CIMMYT), Apdo. Postal 6-641, 06600, Mexico DF, Mexico

You can also search for this author in PubMed   Google Scholar

Editor information

Editors and affiliations.

Buck Semillas S.A, La Dulce, Argentina

National Institute for Agricultural Technology and Animal Husbandry, Marcos Juarez, Argentina

National Southern University, Buenos Aires, Argentina

Rights and permissions

Reprints and permissions

Copyright information

© 2007 Springer

About this paper

Cite this paper.

Dixon, J. (2007). The Economics of Wheat. In: Buck, H.T., Nisi, J.E., Salomón, N. (eds) Wheat Production in Stressed Environments. Developments in Plant Breeding, vol 12. Springer, Dordrecht. https://doi.org/10.1007/1-4020-5497-1_2

Download citation

DOI : https://doi.org/10.1007/1-4020-5497-1_2

Publisher Name : Springer, Dordrecht

Print ISBN : 978-1-4020-5496-9

Online ISBN : 978-1-4020-5497-6

eBook Packages : Biomedical and Life Sciences Biomedical and Life Sciences (R0)

Share this paper

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

• Publish with us

Policies and ethics

• Find a journal
• Track your research