Exploiting grain bioactivity for improved nutrition and health

Intake of both cereal dietary fibre and whole grain has been shown to protect against rapidly expanding chronic diseases such as cardiovascular disease and type 2 diabetes. The mechanisms are as yet not known, but the protection is suggested to be due to the concerted action of dietary fibre and various bioactive compounds such as lignans, phenolic acids, alkylresorcinols, phytosterols, folates, tocopherols and tocotrienols, other vitamins and minerals. Being concentrated in the outer layers of the grain, these compounds are often removed in current milling processes, optimised to deliver products made of refined grains. Foods should be made available to deliver more grain fibre and outer layers of the grains, while also addressing the consumer expectations of palatability and convenience. This demands for new ingredients high in grain phytochemicals and with good technological properties. The natural diversity in grains offers a good basis for tailored fractionation and bioprocessing. The grain chain from plant breeding and crop selection should take into account the nutritional quality criteria set by the end-use. This was the approach in the EU integrated project HEALTHGRAIN running in 2005-2010 (www.healthgrain.org), which addressed the whole grain chain to provide consumers with healthy grain-based foods and ingredients (Poutanen et al 2008). It included studies of consumer expectations, development of a biotechnology toolbox for plant breeding, development of wet and dry milling and novel bioprocessing technologies for grain processing, studies of mechanisms behind the metabolic merits of foods in a series of in vitro, animal and human studies, and identification of health-relevant cereal food criteria. The HEALTHGRAIN diversity screen analysed one hundred and fifty bread wheat lines and 50 other lines of small-grain cereals (spelt, durum wheat, Triticum monococcum, Triticum dicoccum, oats, rye, and barley), selected for diversity in their geographical origin, age, and characteristics. They were grown on a single site in Hungary, and analysed for a range of phytochemicals (tocols, sterols, phenolic acids, folates, alkylresorcinols) and fibre components that are considered to potentially have health benefits. The results showed that it is possible to identify lines with high levels of phytochemicals and dietary fibre, and which also show good yield and processing quality (Ward et al 2009). In the next phase also the effect of environment was studied in a smaller subset of samples grown in four countries in two years (Shewry et al 2010). Having the grain raw material rich in the above mentioned nutritionally interesting compounds, it is important to process it so as to maintain the high nutritional value. Milling processing can be tuned for production of new ingredients (Hemery et al 2007). This necessitates knowledge about distribution of the bioactive compounds in the grain (Barron et al 2007, Hemery et al 2009). Wheat aleurone is an example of novel wheat grain fraction with high levels of potentially health-promoting compounds. It has also been shown that the way of processing influences the bioaccessibility and bioavailability of f.ex. phenolic compounds in the cereal food (Mateo Anson et al 2009). It is thus important to consider cereal product quality as an interplay of the raw material and process-induced changes. References Barron, C., Surget, A. and Rouau, X. Relative amounts of tissues in mature wheat (Triticum aestivum L.) grain and their carbohydrate and phenolic acid composition. Journal of Cereal Science 2007, 45, 88-96. Hemery, Y.; Rouau, X.; Lullien-Pellerin, V.; Barron, C.; Abecassis, J. Dry processes to develop wheat fractions and products with enhanced nutritional quality. Journal of Cereal Science 2007, 46, 327-347. Hemery Y.M., Lullien-Pellerin V., Rouau X.,Abécassis J., Samson M.F., Åman P., von Reding W., Spoerndli C.and Barron C. Biochemical markers: efficient tools for the assessment of wheat grain tissue proportions in milling fractions. Journal of Cereal Science. 2009, 49, 45-64. Mateo Anson, N., Selinheimo, E., Havenaar, R.; Aura, A.-M., Mattila, I., Lehtinen, P., Bast, A., Poutanen, K., Haenen, G.R.M.M. Bioprocessing of wheat bran improves in vitro bioaccessibility and colonic metabolism of phenolic compounds; Journal of Agricultural and Food Chemistry. 2009l 57: 6148-6155 Poutanen, K., Shepherd, R., Shewry, P.R., Delcour, J.A., Björck, I., Kamp, J.W. Beyond whole grain: The European HEALTHGRAIN project aims at healthier cereal foods. Cereal Foods World 2008, 53:32-35. Shewry, P. R.; Piironen, V.; Lampi, A.-M.; Edelmann, M.; Kariluoto, S.; Nurmi, T.; Nyström, L.; Ravel, C.; Charmet, G.; Andersoon, A. A. M.; Åman, P.; Boros, D.; Gebruers, K.; Dornez, E.; Courtin, C. M.; Delcour, J. A.; Rakszegi, M.; Bedo, Z.; Ward, J. L. The HEALTHGRAIN wheat diversity screen: effects of genotype and environment on phytochemicals and dietary fiber components. J. Agric. Food Chem., in press. Ward, J., Poutanen, K., Gebruers, K., Piironen, V., Lampi, A.-M., Nyström, L., Anderson, A., Åman, P., Boros, D., Rakszegi, M., Bedo, Z. and Shewry, P. The HEALTHGRAIN Cereal Diversity Screen: Concept, Results and Prospects. J. Agric. Food Chem. 2008, 56: 9699-9709. Acknowledgment The study is financially supported by the European Commission in the Communities 6th Framework Programme, Project HEALTHGRAIN (FOOD-CT-2005-514008)