In vitro potential of flavonoids from tartary buckwheat on antioxidants activity and starch digestibility

Abstract

SummaryThe effects of various flavonoids of Tartary buckwheat (rutin‐enhanced flavonoid extract [REFE and quercetin‐enhanced flavonoid extract [QEFE]) and individual flavonoids (rutin, quercetin and kaempferol) on the antioxidant activity, inhibition of α‐glucosidases and α‐amylase and starch digestibility were evaluated. Quercetin possessed the highest antioxidant activity and inhibition of α‐glucosidases and α‐amylase activity followed by kaempferol and rutin. REFE and QEFE have similar antioxidant and inhibition of α‐amylase activities, but QEFE has much higher α‐glucosidases inhibition than REFE. Tartary buckwheat flour has the lowest content of rapidly digestible starch and predicted glycaemic index (pGI) compared to maize flour, wheat flour and rice flour. Addition of rutin and quercetin to wheat flour showed a weak or no effect on digestion inhibition, but they inhibited starch digestion under solid complex conditions. Our results may help explain the benefits of supplementing the diet with food rich in flavonoids.