Antioxidant, α-amylase and α-glucosidase inhibitory activities of bound polyphenols extracted from mung bean skin dietary fiber

In this study, bound polyphenols were extracted from mung bean skin dietary fiber by acid hydrolysis or alkaline hydrolysis. It was found that alkaline hydrolysis was more thorough than acid hydrolysis, the highest yield of bound polyphenols was 37.638 (mg FAE/g). In addition, the compositions of bound polyphenols were identified and quantified by UPLC-ESI-QTOF-MS/MS and UPLC-ESI-QqQ-MS/MS. In the study of antioxidant properties, we found that with the increase of polyphenol concentration, the scavenging rate of DPPH free radical, the absorption ability of oxygen free radical and the inhibition of ABAP were increased. Moreover, the inhibition rate of bound polyphenols on α-amylase and α-glucosidase increased in a dose dependent manner. The results could provide perspective for using the bound polyphenols in mung bean skin as the functional components of health food.