Abstract: Inhibitory activities of four proanthocyanidins from different botanical sources against α-amylase and α-glucosidase were studied by using high-throughput starch turbidity method (HtST). Then the interaction between proanthocyanidins and common cereal flours and starches were researched for the purpose of providing a theoretical basis for further development of hypoglycemic staple foods. The results showed that proanthocyanidins from grape seeds and sorghum possessed higher inhibitory activities against α-amylase and α-glucosidase than those from cranberry and apple. Binding of proanthocyanidins to the main food components affected the inhibitory activity of proanthocyanidins. The results indicated that glutinous rice, bulk rice, sorghum could bind grape seed proanthocyanidins and reduce the inhibitory activity of proanthocyanidins against α-amylase and α-glucosidase. However, corn starch, tapioca starch, potato flour, commercial edible starch, rice flour, sago, millet, corn flake, sweet potato flour, black rice, and black bean almost had no binding interaction with grape seed proanthocyanidins, and thus they were ideal food materials to maintain or enhance the inhibitory activity of proanthocyanidins against carbohydrate digestive enzymes.

Key words: proanthocyanidins, α-amylase, α-glucosidase, cereals, binding interaction