New approaches for enhancing health benefits of cereal products

Cereals are an essential part of our daily diet. Nutritional guidelines recommend increased consumption of especially whole grain foods, and there is increasing epidemiological evidence on their disease-preventive role. There is also growing consumer interest in health aspects of food, including functional food products with specific physiological functions of health relevance. However, consumers also demand good sensory properties and convenience, and safety remains a prerequisite. This means various challenges for research as well as development, production and marketing of grain foods. Cereal foods and health Cereals are among the most important sources of dietary fibre, and thus play an important role in gut health. Grains also are the major source of dietary carbohydrates, and so special attention should be put to their role in glucose metabolism. Especially with the expanding incidence of type 2 diabetes this is an important challenge for development of new cereal foods. As obesity is the major nutritional problem in several parts of the world, the potential of cereals in weight control is another interesting issue for the future. The progress in research of the genetics behind chronic diseases, together with the rapidly developing tools for studying nutrient-gene interactions, challenge also cereal-related nutrition research to study the mechanisms behind the health benefits. Consumer attitudes and sensory quality We should develop modern, nutritionally optimised cereal foods that meet consumer expectations. Thus, to tailor and successfully communicate the benefits of various cereal food concepts, we need better understanding of factors that are critical for consumer choices. Appealing flavour and mouthfeel are the key issues behind choices and research into the factors defining sensory quality of the cereal matrix is also needed. Without this knowledge we cannot thrive in developing cereal foods which would be repeatedly chosen and eaten, i.e. which could deliver their health benefits. Bioactive power of grains In addition to useful macronutrients and dietary fibre, grains contain a wide range of bioactive phytochemicals (lignans, sterols, alkylresorcinols, phenolic acids), vitamins (folate, tocopherols and -trienols), soluble indigestible carbohydrates and other associated components such as indigestible protein. These are located in the outer layers of the grain and are thus often discarded in milling and refining processes. There is growing evidence about the contribution of these compounds to the health-promoting effects of whole grains. Here we have still much to learn, and will find various new ways of providing more of these cereal bioactive factors to consumers. Material science Cereal foods are complex multiphase biopolymer systems. Food macro- and microstructure determines our ability to chew food, which is important for textural sensation, but also for physiological responses. Food structure has great influence on the rate of starch hydrolysis in humans and on glucose and insulin responses. It also influences absorption of other nutrients, fermentability of dietary fibre and bioavailability of bioactive compounds. Understanding the cereal matrix from nano- to macroscale provides the basis for successful cereal product design. New technologies New technological tools enable development of tailored products and ingredients. Also innovative and/or optimised use of conventional technologies combined with knowledge of health effects may produce new health-beneficial products. Especially bioprocessing offers new means of designing the properties of cereal foods: enzymes and enzyme inhibitors are being developed for specific processing, starter cultures have potential also for modulating health effects, and germination has been shown to increase levels of bioactive compounds. Controlled bioavailability The mechanisms and rates of uptake of cereal components in the human gastrointestinal tract determine the physiological effects of cereal foods. We are learning about the factors controlling the pharmacokinctics of the bioactive phytochemicals, such as lignans, alkylresorcinols and phenolic acids in grains and about their metabolism in humans. This knowledge provides a starting point for linking cereal intake to genetic and cellular function. It is also needed for development of ingredients and products for optimised delivery of physiologically important components. Also with respect to macronutrients it is important to understand the mechanisms behind their absorption and uptake, for example to be able to retard and reduce glycaemic responses of starch in cereals.
Conclusion
Cereal foods constitute a wide range of products with variable health effects. By applying methods of modern consumer and nutrition research, by optimising the amounts of bioactive grain compounds and by developing tailored processing methods we will be able to exploit the health benefit potential of grains. This requires co-ordinated interdisciplinary research approaches, with adequate communication both within the scientific community and with the industries and consumers.