Chapter 113 - Extracts from Purple Wheat (Triticum spp.) and Their Antioxidant Effects

Abstract

This chapter explores the effects of purple wheat on health and nutrition. When their extracts are assessed for antioxidant effects, purple wheat have been found to have potential applications to health promotion and disease prevention. Extracts from purple wheat differ in their antioxidant effects, depending on the extraction methods employed as well as genotypic and environmental effects. The extraction, done by using acidic methanol, is mainly focused on phenolic compounds (or phenolics). Among the purple wheats (Charcoal, Konini, and Indigo), Charcoal had the highest antioxidant activity, likely resulting from its high content of total phenolics, anthocyanins, and flavonoids. The total phenolic acid content in purple wheat genotypes varied from 109 to 114 mg/100 g. Ferulic acid was the predominant acid, constituting up to 79% of the total acids. The aqueous acetone extracts of purple wheat were also used for detecting proanthocyanidins, which are known to exhibit antioxidant effects. Other phenolic acids identified included vanillic, p-coumaric, and sinapic, with caffeic acid present in trace amounts (< 1 mg/100 g). A high concentration of ferulic acid increases dimerization. Anthocyanins are the primary pigments in purple wheat and possess strong antioxidant activity. To date, 10 types of anthocyanins have been identified in purple wheat. Cyanidin 3-glucoside is the most abundant anthocyanin, followed by peonidin 3-glucoside. They represent approximately 31% and 16%, respectively, of the total anthocyanins. Flavonoids are an important class of phenolic compounds, accounting for approximately two-thirds of the dietary phenols. The adverse effects and reactions associated with common wheat may also be applicable to purple wheat.