Dynamic changes of nutrients, isoflavone composition and antioxidant activities during liquid-state fermentation of soybean embryo homogenate by Ganoderma lucidum

Abstract

This study aims to explore compositional changes of oligosaccharides, amino-type nitrogen, free amino acids volatile compounds, isoflavones, total phenol, total flavonoid, and antioxidant capacities during liquid-state fermentation (LSF) of soybean embryo homogenate (SEH) by Ganoderma lucidum to improve usability as functional food material. Raffinose and stachyose were almost completely hydrolyzed into monosaccharides such as fructose, glucose and galactose after 2 days of fermentation. After 5 days of fermentation, the contents of amino-type nitrogen and total free amino acids increased 7.0-fold and 2.4-fold, respectively, compared to the control group. Most of isoflavone glycosides were almost hydrolyzed into aglycones after 2 days and thereafter some of isoflavone aglycones were transformed into ortho-hydroxyisoflavones (OHIs). Total phenol, total flavonoid and antioxidants activities were significantly increased during the fermentation period. The result indicates that LSF of soybean embryo by G. lucidum can potentially improve acceptability and usability of soybean embryo as functional food material.