Research progress in antioxidant activity of whole grain

Whole grain is a significant source of dietary antioxidants due to its abundant antioxidant compounds in bran and germ, such as phenolic acid, anthocyanin, proanthocyanidin, γ -oryzanol and alkylresorcinols. Whole grain food is widely consumed all over the world. The in vitro and ex vivo antioxidant activities of whole grain do not well reflected in vivo. The physiological environment, digestive absorption and metabolism were three key factors affecting in vivo antioxidant activity of whole grain. Recent researches revealed that the antioxidant activities of pigmented whole grain were higher than that of common whole grain, and its in vitro and ex vivo antioxidant effects were consistent to in vivo antioxidant effect. The predominant antioxidant compounds in whole grain were introduced in detail. The methods and their principles of in vitro, ex vivo and in vivo studies were compared. Recent advances in research on antioxidant activities of pigmented whole grain and common whole grain were reviewed with the purposes to provide references for better evaluation of the antioxidant activity of whole grain, theory basis for product development of whole grain food, and references for reasonable consumption of whole grain food to balance diet structure.