Anthocyanins, Deoxyanthocyanins and Proanthocyanidins as Dietary Constituents in Grain Products
Anthocyanins, deoxyanthocyanins and proanthocyanidins (condensed tannins) are important dietary flavonoids, but are not widely distributed among the commonly consumed cereal grains. However, the anthocyanins are major phenolic constituents of specialty pigmented grains, including maize, rice, wheat and barley, whereas the deoxyanthocyanins are unique to sorghum. Some varieties of sorghum, barley and finger millet also accumulate nutritionally relevant levels of the proanthocyanidins. The cereal anthocyanin and deoxyanthocyanin pigments are increasingly important, not only due to growing evidence for their health benefits against obesity, diabetes, cardiovascular disease and other diseases linked to chronic inflammation, but also as attractive and functional natural food colorants. The cereal polymeric proanthocyanidins have strong potential as natural ingredients to combat obesity and excess calorie intake and their associated negative health impacts as a result of their ability to bind to and reduce the digestibility of macronutrients, especially carbohydrates and proteins. Cereal grains are highly attractive as natural sources of the bioactive flavonoids due to their widespread production and consumption, as well as ease of storage, handling and processing.