Production of Sufu, a Traditional Chinese Fermented Soybean Food, by Fermentation with Mucor flavus at Low Temperature

This study evaluated biochemical changes, especially those related to protein degradation, occurring in sufu fermentation with Mucor flavus at low temperature. The effects of incubation temperature on M. flavus growth, biomass accumulation and protease production were described. Results indicated that M. flavus could grow well on the surface of soybean curd and produce considerable protease to degrade soybean proteins during sufu fermentation at lower temperature such as 15 C. Almost no subunits of protein could be observed after maturation for 8 weeks in M. flavus-type sufu. Post-fermentation was the main stage responsible for the hydrolysis of protein together with the increase in the content of amino-type nitrogen and free amino acid. Our results demonstrated that M. flavus had possible application as an alternative strain for sufu manufacturing at low temperature.