Phytochemicals of Whole Grains and Effects on Health

Grains are important raw materials for staple food products in the diet. Since they are not only a good source of carbohydrate content, provides for daily energy intake, but also protein, vitamins B-complex source for an adequate and balanced diet. Moreover, in recent times, it was elucidated that whole grains involve several bioactive compounds namely phytochemicals. Phytochemicals are non-nutritive dietary bioactive compounds and secondary metabolites generated by plants to protect themselves against environmental stress or threats. Whole grain phytochemicals comprise of dietary fiber as beta-glucan, arabinoxylan, inulin, resistant starch; phenolic compounds as phenolic acids, anthocyanins, tocols (tocotrienols and tocopherols), lignans, alkylresorcinols, carotenoids (lutein, zeaxanthin, etc.) and other phytochemicals as phytic acid, phytosterols, gamma-oryzanol, avenanthramides, benzoxazinoids. Phytochemicals could improve health and/or hinder some chronic diseases by means of whose antioxidant, anticarcinogenic, antimicrobial, antimutagenic, and anti-inflammatory activities. Epidemiological studies support that consumption of whole grains and food products are related to decreasing the risk of coronary heart disease, type 2 diabetes, obesity, oxidative stress, and some cancer types. The phytochemicals are mainly present in outer layers of grains as germ and bran parts. For this reason, the content of whole grains phytochemical is higher than refined ones owing to the milling process. In some cases, the processing negatively affects the bioactive components but there are contradictory remarks and studies about the stability of phytochemicals during processing. This chapter will briefly discuss not only phytochemicals of whole grains and effects on health but also the effect of processing on whole grain phytochemicals.