Changes in some nutritional components of soymilk during fermentation by the culinary and medicinal mushroom Grifola frondosa

Abstract

Soymilk was fermented by Grifola frondosa and the changes in the contents of polysaccharide, oligosaccharide, crude protein, B-vitamins, free amino acids and isoflavones were analyzed. Polysaccharide and free amino acids were increased by the fermentation of G. frondosa while crude protein was reduced. The flatulence factor (e.g. stachyose and raffinose) was significantly decreased and the contents of raffinose and stachyose were decreased from 1.44 g l−1 and 2.10 g l−1 to 0.75 g l−1 and 0.04 g l−1, respectively. The contents of thiamin and niacin were increased by the fermentation of G. frondosa from 3.27 mg l−1 and 3.84 mg l−1 at the beginning to 10.82 mg l−1 and 8.74 mg l−1 after 144 h of fermentation, respectively. Some isoflavone glycosides were converted to aglycones and the content of daidzein was increased by the fermentation of G. frondosa. The results suggested fermentation by G. frondosa could improve the acceptability and health properties of soymilk.