Suppressive Effect of the α-Amylase Inhibitor Albumin from Buckwheat (Fagopyrum esculentum Moench) on Postprandial Hyperglycaemia

Inhibiting starch hydrolysis into sugar could reduce postprandial blood glucose elevation and contribute to diabetes prevention. Here, both buckwheat and wheat albumin that inhibited mammalian alpha-amylase in vitro suppressed blood glucose level elevation after starch loading in vivo, but it had no effect after glucose loading. In contrast to the non-competitive inhibition of wheat alpha-amylase inhibitor, buckwheat albumin acted in a competitive manner. Although buckwheat alpha-amylase inhibitor was readily hydrolysed by digestive enzymes, the hydrolysate retained inhibitory activity. Together with its thermal stability, this suggests its potential use in functional foods that prevent diabetes.