Exploiting Underutilised crops

Abstract

Food Science and TechnologyVolume 37, Issue 1 p. 36-39 SpotlightFree Access Exploiting Underutilised crops First published: 08 March 2023 https://doi.org/10.1002/fsat.3701_9.xAboutSectionsPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Madalina Neacsu and Sylvia H. Duncan of the Rowett Institute, University of Aberdeen, discuss the potential of several crops and their by-products as sustainable sources of nutrients to bio-diversify and meet the UK dietary requirements1-3 Figure 1Open in figure viewerPowerPoint Broad beans and Broad bean hulls Figure 2Open in figure viewerPowerPoint Buckwheat seeds and Buckwheat hulls Figure 3Open in figure viewerPowerPoint Hemp seeds and Hemp hulls Background Global challenges, including the degradation of ecosystems, frequent crop failures due to climate change, the SARS Cov-2 pandemic, and interruption in food supplies, significantly impacted food supply chains. Countries worldwide will, therefore, need help to meet the WHO nutrition target by 2025 or the UN sustainable development goal's nutrition target by 2030. Despite the UK's temperate climate, weather patterns are also changing following anthropogenic activity resulting in hotter summers and wetter winters that have already had a significant impact on crop production. In the UK, approximately 10m t of wheat (Triticum aestivum) are produced per annum. Wheat is the most widely grown and consumed arable crop in the UK and globally, however, production has declined by approximately 30% in the past few years, mainly due to extreme weather patterns. As wheat is primarily considered to grow best in cooler climates, scientists and wheat producers are consequently looking to diversify wheat varieties grown in the UK to enhance tolerance to climate change. Furthermore, globally, consideration needs to be given to reducing greenhouse gas levels and the delivery of a greener, healthier, and sustainable food system. For example, to address the climate crisis, Scotland needs to achieve a major reduction in greenhouse gas emissions by 2030 and to have a net-zero carbon economy by 2045. Macdiarmid and colleagues published a report in 2018[1] showing that in the UK diet, approximately a third of protein came from plant-based products, with the total supply being double the amount needed to satisfy population requirements. This was not the case for dietary fibre, possibly due to the loss incurred by processing crops (i.e., cereals) into refined products. Moreover, the report concluded that if all the cereal products consumed in the UK were unrefined (like wholemeal flour, wholemeal bread, wholegrain breakfast cereals, whole-wheat pasta, and brown rice), then the supply of fibre as non-starch polysaccharides (NSP) would increase to around 23 g/capita/day. The UK also relies on imported foods to meet micronutrient requirements such as for iron and zinc. With the new daily recommendation guidelines, the UK government suggests consuming 30 g of fibre per day. However, it is estimated that the average fibre consumption by adults is 18 g/d[2]; therefore, increased consumption of high-fibre crops may help to increase overall fibre consumption. Cereals routinely supply over half of all dietary fibre intake, and a substantial proportion of the supply of micronutrients comes from fortified cereal products. To meet some of these demands in terms of fibre and micronutrients in the UK, the food industry's underutilized crops, such as broad bean, hemp and buckwheat and/or their agricultural and food by-products may offer an attractive option to meet current and future nutritional needs. These crops and by-products represent a sustainable source of fibre, minerals, and phytochemicals[3]. Some of these crops are also high in phytates, which may reduce mineral bioavailability and the effectiveness of fortification. Regarding health, high-fibre diets are likely to contribute to reducing several chronic diseases, including cardiovascular disease (CVD) and colorectal cancer. It is becoming increasingly apparent that there may be benefits to exploiting novel, underutilised crops and their high fibre by-products as sources of nutrients. Apart from estimating their nutrient chemical content, it is vital to understand their suitability as potential food ingredients. To do this, it is key to test their fermentability (when used as dietary fibre), improve their mineral absorption (i.e., reduction of phytic acid), and assess their component's metabolism at systemic (early gastro intestinal tract – GIT) and colon levels. Here, the potential of several crops and their potential by-products as sources of nutrients to bio-diversify and meet the UK dietary requirements is discussed. 1. Wheat bran, currently main source of carbohydrates (dietary fibre) in UK Wheat (Triticum aestivum) is a major crop in the UK, occupying approximately 65% of the arable area. The main use of wheat is in producing bread and breakfast cereals. Milled wheat bran is rich in fibre, minerals, vitamins, and phenolic compounds, and a potential advantage of consuming a wheat bran-rich diet is that the fibre can increase gut transit and faecal bulking, thereby reducing exposure to the cells lining the colonic wall (colonocytes) of toxigenic products that may be potential carcinogens. Much of the fibre is likely to escape digestion by the host enzymes in the upper GIT, therefore, it becomes available for fermentation by the dense population of mostly anaerobic bacteria in large intestine (colon). These fibres are fermented to short-chain fatty acids (SCFAs), with acetate, propionate, and butyrate being the major ones found in the large intestine. Butyrate is generally considered beneficial for health, as it is the major energy source for the colonocytes and has potential anti-inflammatory effects. As wheat bran is also a rich source of phytochemicals, specific gut bacterial species can transform these into metabolites with antioxidative properties. The main phenolic compound in wheat bran is ferulic acid, which mainly exists bound to polysaccharides and other wall polymers but can be released by bacterial enzymes (esterases). The carbohydrate component of wheat bran comprises insoluble fibre predominantly made up of arabinoxylan (70%) and cellulose (24%). Several studies observed that, using in vitro human colonic model fermenter systems containing wheat bran in nylon bags and inoculated with mixed faecal microbiota from four different donors, a similarly small number of species became enriched on this substrate from the bacterial communities examined. This is surprising given the level of interindividual variation in gut microbial composition. These included species belonging to the butyrate producing Eubacterium and Roseburia genera. Walker and co-workers observed a similar specific enrichment in wheat-bran human studies[4]. Subsequently, Duncan et al. (2016) revealed cooperation within the microbiota in converting the main phenolic found in wheat bran, ferulic acid, which mainly exists in the bound form by human colonic bacteria[5]. During the wheat bran degradation process, the bound ferulic acid was released via specialist primary degraders and converted to phenyl propionic acid derivatives via hydrogenation, demethylation, and dehydroxylation. The products have both antioxidant and anti-inflammatory activities. Separately, when human volunteers consumed wheat bran in the form of breakfast cereals, a recommended serving (40 g) of wheat bran cereal increased the total microbial SCFAs levels, particularly butyrate levels, reduced colonic inflammation and increased plasma folate levels in humans[6]. 2. Broad beans, buckwheat and hemp as alternatives sources of nutrients in the UK Some underutilised sustainable food crops in the UK are broad beans, buckwheat, and hemp. Research shows these are sources of protein, insoluble fibre, and minerals such as magnesium, phosphorus, potassium, calcium, manganese, and zinc[3]. Moreover, buckwheat is rich in bioactive phytochemicals such as pelargonidin, epicatechin, quercetin, and caffeic acid; hemp is rich in p-coumaric acid, cyanidin, and gentisic acid; and broad beans are the richest source of ferulic acid[3]. 2.1. Broad bean Broad bean (Vicia faba) is a legume produced in large quantities in the UK, with 740,000 tonnes of the dried (fava) beans being harvested each year on around 170,000 hectares – making the UK the largest producer of broad beans in Europe[7]. A large proportion of broad bean seed weight is composed of hulls (the outer bean covering) that are largely discarded, despite the hulls being high in fibre (49%). Understanding the nutritional and health potential of bean hulls involves assessing the bioavailability and metabolism of the nutrients and bioactive molecules early in the GIT and at the colon level. Nutritionally relevant concentrations of the metabolites can further inform on the potential health applications and subsequent functional food development. Therefore, a human dietary intervention study[8] involving healthy volunteers was carried out following acute and chronic (three days) consumption of broad bean hulls fortified bread. 2.2. Buckwheat Buckwheat (Fagopyrum esculentum) is a flowering plant cultivated for its grain-like seeds; although it is a pseudocereal, it can be used in cooking the same way as cereals due to its high starch content. The consumption of buckwheat-rich foods promoted satiety and the decrease in plasma branched-chain amino acids and phenylalanine and tyrosine in plasma human volunteers[9]. Therefore, apart from being a rich source of nutrients, buckwheat could be used in developing functional ingredients to prevent chronic diseases or in weight control strategies. The buckwheat dietary fibre is concentrated in the hull; 100 g of hulled buckwheat contributes up to half the daily dietary recommendation for fibre as NSP[10], with the majority of the NSP being in the insoluble form. Although hulled buckwheat has a similar monomeric structure composition to wheat bran, the ratio between the monomers differs. Thus, it is important to explore buckwheat hull fermentability further to understand and adopt it as a source of fibre in the human diet. Buckwheat hulls could contribute to boosting and diversifying fibre consumption, especially in western-type diets such as those consumed in the UK. Buckwheat could contribute to delivering the recommended nutrient intake for several minerals; 100 g of buckwheat could deliver 83% of the daily reference nutrient intake (RNI) for magnesium, 78% for phosphorus, 40% for iron, 48% for zinc, 50% for copper, 88% for molybdenum, and the daily RNI for manganese and chrome, as well as being a rich source of calcium and iron[10]. Nutritional studies should establish the bioavailability of buckwheat microelements and further explore their potential as functional ingredients for food fortification to tackle malnutrition. 2.3. Hemp Hemp (Cannabis sativa L.) has the potential as a carbon-neutral crop that could play a key role in developing and expanding a low-CO2, environmentally responsible industry, establishing a new food crop in the UK. Agricultural hemp has an excellent nutritional profile, with hemp flour being a rich source of protein (36%), dietary fibre (26%), healthy fats (6%), and micronutrient minerals, including magnesium, phosphorus, potassium, calcium, and zinc. Consumption of hemp-rich bread beneficially modulated several gut hormones[9]. Gut-derived hormones influence various physiological processes, including glucose homeostasis, centrally mediated appetite control, and adiposity. These could be targets for novel obesity and diabetes nutritional therapies. It is essential to understand the effect of plant-based foods on the modulation of these hormones as diets rich in high-protein crops are inversely associated with the risk of metabolic syndrome[11], with lower incidence of Type 2 Diabetes (T2D)[12], and with the improvement of several biomarkers of CVD[13]. Hemp flour is a particularly rich source of zinc, and 100 g of flour could deliver half of the RNI and could be a cost-effective approach to control zinc deficiencies. Moreover, the most abundant phytochemicals in hemp flour are p-coumaric acid and lignans (such as secoisolariciresinol and syringaresinol) found in bound form[3] This suggests they would be available later in the GIT to be released by the colonic microbiota. The consumption of hemp flour could be efficacious in increasing the intake of dietary lignans. Human intervention studies showed that high plasmatic concentrations of lignans were associated with a lower risk of colon cancer[14]. This indicates that high-fibre hemp-based products could contribute towards daily nutrient recommendation in terms of fibre and minerals but also could be beneficial to colonic health. Future perspectives, further considerations and concluding remarks The decline in wheat production in the UK highlights the need for alternative crops that are climate resilient in order to sustain a healthy nation. Climate-tolerant buckwheat and hemp are good sources of dietary fibre and minerals. This is important given the already low levels of fibre consumption in the UK. Delivering this on time will require the combined efforts of government departments, farmers, scientists, and food producers. From a research perspective, it is important to identify good alternative sources of fibre, including by-products from crops, to help to drive a circular economy, and to investigate their digestibility and fermentability by gut bacteria to promote health. This will likely enhance the fermentability of certain cereal crops and fibre-rich by-products that are likely poorly fermented by human gut bacteria. Moreover, certain crops may also be rich in phytic acid, which naturally occurs in cereals. High levels of foods rich in phytic acid are likely to reduce the absorption of minerals, for example, calcium required for maintaining bone density and zinc for immune health. Certain gut bacteria may, however, possess phytase activity and therefore have a role in diminishing this effect, but this requires further investigation. Hemp, buckwheat, and broad bean could constitute key ingredients of a healthy, sustainable diet as valuable sources of dietary amino acids; hemp and buckwheat beneficially modulate gastrointestinal hormones and promote satiety[9]. Moreover, they represent promising candidates for flour fortification with phenolic acids, anthocyanins, and other flavonoids[15]. Furthermore, these could be used as active functional ingredients for nutritional therapies and contribute to boosting our diets’ fibre content and mineral requirements. Additionally, these products should be investigated to prevent conditions such as type 2 diabetes mellitus. Modern functional foods should not only provide a proven health benefit or deliver the required nutrients; they should contribute to sustainable goals by finding solutions to tackle agricultural waste and contribute to a greener environment. Underutilised crops such as hemp, buckwheat, and broad bean and their by-products, such as hulls, could be ideal candidates to address this need. Dr. Madalina Neacsu, Research Fellow and Dr. Sylvia H. Duncan, Senior Research Fellow The Rowett Institute, University of Aberdeen References 1Macdiarmid, J. I., Clark, H., Whybrow, S., de Ruiter, H., McNeill, G. 2018. Assessing national nutrition security: The UK reliance on imports to meet population energy and nutrient recommendations. PLoS One 13: e0192649. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0192649 2 Public Health England. 2015. SACN Carbohydrates and Health Report. Available from: https://www.gov.uk/government/publications/sacn-carbohydrates-and-health-report 3Multari, S., Neacsu, M., Scobbie, L., Cantlay, L., Duncan, G., Vaughan, N. J., Stewart, D., Russell, W. R. 2016. Nutritional and Phytochemical Content of High-Protein Crops. Journal of Agricultural and Food Chemistry 64: 7800- 7811. Available from: https://pubmed.ncbi.nlm.nih.gov/27299956/ 4Walker, A. W., Ince, J., Duncan, S. H., Webster, L. M., Holtrop, G. et al. 2011. Dominant and diet-responsive groups of bacteria within the human colonic microbiota. ISME Journal 5: 220- 230. Available from: https://www.nature.com/articles/ismej2010118 5Duncan, S. H., Russell, W. R., Quartieri, A., Rossi, M., Parkhill, J. et al. 2016. Wheat bran promotes enrichment within the human colonic microbiota of butyrate-producing bacteria that release ferulic acid. Environmental Microbiology 18: 2214- 2225. Available from: https://pubmed.ncbi.nlm.nih.gov/26636660/ 6Neacsu, M., Anderson, S. E., Verschoor, P., Vaughan, N. J., Horgan, G. W. et al. 2021. Consumption of a Recommended Serving of Wheat Bran Cereals Significantly Increases Human Faecal Butyrate Levels in Healthy Volunteers and Reduces Markers of Inflammation Ex Vivo. Recent Progress in Nutrition 1: 002. Available from: https://www.lidsen.com/journals/rpn/rpn-01-04-002 7Sepngang , K., Vickers, R., Muel, F., Smadja, T. & Mergenthaler, M. 2019. Market of grain legumes in the UK. Results of the EU-project LegValue. Forschungsberichte des Fachbereichs Agrarwirtschaft, Soest. Nr. 47. Available from: https://www.legvalue.eu/media/1346/market-analysis-of-legumes-in-the-uk.pdf 8 US National Library of Medicine. 2022. The Impact of Broad Bean Hull on Blood Glucose Control and Gut Health. Available from: https://clinicaltrials.gov/ct2/show/NCT05252013 9Neacsu, M., Vaughan, N. J., Multari, S., Haljas, E., Scobbie, L. et al. 2022. Hemp and buckwheat are valuable sources of dietary amino acids, beneficially modulating gastrointestinal hormones and promoting satiety in healthy volunteers. European Journal of Nutrition. 61: 1057- 1072. Available from: https://pubmed.ncbi.nlm.nih.gov/34716790/ 10Neacsu, M., De Lima Sampaio, S., Hayes, H. E., Duncan, G. J., Vaughan, N. J. et al. 2022. Nutritional Content, Phytochemical Profiling, and Physical Properties of Buckwheat (Fagopyrum esculentum) Seeds for Promotion of Dietary and Food Ingredient Biodiversity. Crops 2: 287– 305. Available from: https://www.mdpi.com/2673-7655/2/3/21/review_report 11Martínez-González, M. A., Sánchez-Tainta, A., Corella, D. et al. 2014. A pro-vegetarian food pattern and reduction in total mortality in the Prevención con Dieta Mediterránea (PREDIMED) study. American Journal of Clinical Nutrition. 100: 320S– 328S. Available from: https://pubmed.ncbi.nlm.nih.gov/24871477/ 12Satija, A., Bhupathiraju, S. N., Rimm, E. B., Spiegelman, D., Chiuve, S. E. et al. 2016. Plant-based dietary patterns and incidence of type 2 diabetes in US men and women: results from three prospective cohort studies. PLoS Medicine 13:e1002039. Available from: https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002039 13Neacsu, M., Fyfe, C., Horgan, G., Johnstone, A. M. 2014. Appetite control and biomarkers of satiety with vegetarian (soy) and meat-based high-protein diets for weight loss in obese men: a randomized crossover trial. American Journal of Clinical Nutrition. 100: 548– 558. Available from: https://pubmed.ncbi.nlm.nih.gov/24944057/ 14Landete, J. M. 2012. Plant and mammalian lignans: A review of source, intake, metabolism, intestinal bacteria and health. Food Research International 46: 410– 424. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0963996912000087 15Neacsu, M., Christie, J. S., Duncan, G. J., Vaughan, N. J., Russell, W. R. 2022. Buckwheat, Broad Bean and Hemp Flours Fortified with Anthocyanins and Other Bioactive Phytochemicals as Sustainable Ingredients for Functional Food Development. Nutraceuticals 2: 150- 161. Available from: https://www.mdpi.com/1661-3821/2/3/11 Extra references: 1Leitch, E. C. M., Walker, A. W., Duncan, S. H., Holtrop, G., Flint, H. J. 2007. Selective colonisation of insoluble substrates by human faecal bacteria. Environmental Microbiology 9: 667- 679. Available from: https://ami-journals.onlinelibrary.wiley.com/doi/10.1111/j.1462-2920.2006.01186.x 2Russell, W. R., Gratz, S., Duncan, S. H., Holtrop, G., Ince, J. et al. 2011. High protein, reduced carbohydrate diets promote metabolite profiles likely to be detrimental to colonic health. American Journal of Clinical Nutrition 93: 1062- 1072. Available from: https://pubmed.ncbi.nlm.nih.gov/21389180/ 3 Department of Health. 1991. Dietary reference values: a guide. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/743790/Dietary_Reference_Values_-_A_Guide__1991_.pdf Volume37, Issue1March 2023Pages 36-39 FiguresReferencesRelatedInformation