Antioxidant activities and inhibitory effects of free and bound polyphenols from date (Phoenix dactylifera L.) seeds on starch digestive enzymes

Abstract

Date (Phoenix dactylifera L.) seeds have gained interest as a valuable by-product of  the date fruit industry and have been identified as a rich source of functional and bioactive ingredients. In this study, date seeds from five varieties (Medjool, Deglet Nour, Barhee, Bou Sthammi and Dayrie) cultivated in Australia were analysed for their total phenolic and flavonoid contents, ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), and in-vitro inhibition against α-amylase and α-glucosidase. The date seed powders (DSP) were extracted with acetone-methanol-water (2:2:1, v:v:v) to obtain free polyphenols.  The bound polyphenols were extracted from the residual..