Release of soybean (Glycine max L.) polyphenols by solid-state fermentation with Eurotium cristatum and its effect on glycemic index

Abstract

Abstract In this study, soybean (Glycine max L.) by using solid-state fermentation (SSF) technology and was fermented by Eurotium cristatum. The influence of SSF on the composition of free polyphenols (FP), bound polyphenols (BP), total polyphenols (TP) and FP in soybean before and after fermentation was investigated. The results showed that the content of FP and TP increased significantly during SSF process. After 12 days of SSF, FP, BP and TP in soybean were approximately 3.98-, 1.38-, 3.16 higher, respectively. HPLC-MS/MS analysis detected 10 kinds of substances were newly formed in the FP during SSF process. Furthermore, SSF with E. cristatum considerably scaveng effects against ABTS·+ and DPPH radical, reducing power, and chelating ability of soybeans, and its hypoglycemic activity was significantly enhanced. And the FP of soybeans after fermentation can reduce the glycemic index (GI) of common foods. This research demonstrated that solid-state bioprocessing with E. cristatum is an effective way to increase polyphenols content and hypoglycemic ability of soybeans. Compared with unfermented soybean, fermented soybean products might have great potential in hypoglycemic agents or be used as a new natural source applied in hypoglycemic.