Effects of Fermentation Temperature on the Content and Composition of Isoflavones and β-Glucosidase Activity in Sufu

抄録

Sufu is a popular fermented tofu product in China. The low quality of sufu produced in the hot summer is a big problem in sufu manufacture, so we prepared sufu at two different temperatures, 26 °C as normal and 32 °C as high temperature, and the effects of temperature on isoflavones and β-glucosidase activity were investigated. Fermentation temperature did not cause significant differences in the recovery of isoflavones, but resulted in a different redistribution of isoflavone isomers in sufu. Sufu fermented at 26 °C was richer in isoflavone aglycones than at 32 °C; the enrichment of isoflavone aglycones might have the advantage of enhancing the physiological function. No 6″-O-malonyl-glucosides were detected in sufu fermented at 26 °C, whereas some 6″-O-malonyl-glucosides were found at 32 °C. A fermentation temperature of 26 °C benefited the β-glucosidase production by fungi, which contributed to valid conversion from β-glucosides to aglycones. It was also found that β-glucosidase converted β-glucosides more effectively than 6″-O-malonyl-glucosides and 6″-O-acetyl-glucosides into aglycones.