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Chapter 7: Micronutrients and Phytochemicals in Wheat Grain


Vieno Piironen, Anna-Maija Lampi, and Päivi Ekholm, Department of Applied Chemistry and Microbiology, University of Helsinki, Helsinki, Finland; Marjatta Salmenkallio-Marttila and Kirsi-Helena Liukkonen, VTT Technical Research Centre of Finland, VTT, Finland

WHEAT: Chemistry and Technology, Fourth Edition
Pages 179-222
DOI: https://doi.org/10.1094/9781891127557.007
ISBN: 978-1-891127-55-7






Abstract

Wheat and wheat-based foods are a major source of nutrients for people in many regions of the world (Betschart 1988). They are important sources of energy, proteins, carbohydrates/fiber, vitamin E, several B vitamins, and minerals. Where cereals constitute the bulk of the diet, even a small change in the content of a limiting nutrient could have a profound effect on the overall nutritional quality of the diet (Davis et al 1984a). Furthermore, whole grains contain significant amounts of functional, biologically active components (Slavin et al 2001, Jones et al 2002, McKevith 2004). There is a growing interest in the potential health benefits of phytochemicals, such as phenolic acids, lignans, and phytosterols, which are not classified as nutrients.

Generally, whole grains are among the healthiest food choices that individuals make (Anderson 2003). Evidence suggests that regular consumption of whole grain may have a role in the prevention of several chronic diseases, such as coronary heart disease (CHD), diabetes, and certain types of cancer (Slavin 2000, Jones et al 2002, Koh-Banerjee and Rimm 2003, McKevith 2004). However, the exact mechanisms by which cereals convey beneficial effects are not clear. It is likely that a number of factors are involved (McKevith 2004).

Nutrients and phytochemicals are unevenly distributed in the kernel; germ and bran are generally the richest fractions. Refining thus reduces the contents of nutrients and other bioactive components (Slavin et al 2001, Truswell 2002, McKevith 2004). For example, most of the antioxidants in grains are contained in bran and germ (Miller et al 2000). As research continues on the protective components of whole grains, it will thus be critical to define food-processing techniques that can retain or concentrate the protective components (Slavin et al 2001).

Dietary habits, i.e., which wheat products are consumed and which parts of the grains are utilized in these products, finally determine the overall significance of wheat in nutrition. In this chapter, the focus is on vitamins, minerals, and bioactive compounds such as phytosterols and phenolics.