Abstract:In order to investigate the effects of fermentation strains and the method of making music on the process of bean paste making, the study applied PNM003 and Huniang 3.042 Aspergillus oryzae to the disk fermentation and traditional open fermentation of bean paste, respectively, and examined the differences in environmental factors, microbial counts, enzyme activity, physical and chemical indexes, free amino acids, and volatile compositions of the process of making music in several kinds of bean pastes. The results showed that there were some differences in the indicators of the different types and strains of bean curd-making process. Compared with the open fermentation process, the disk fermentation has stable material temperature (30.8~34.4℃) and environmental humidity (96.0~97.2%rh), which can significantly improve the number of molds and enzyme activity performance in the process. In addition, the total acid content was lower (1.00 g/100g), the sensory quality was better, and the free amino acid flavor was more harmonized in the bean curd prepared by PNM003 under the disk fermentation conditions. The analysis of volatile components showed that, under the same brewing method, the volatile components of bean curd prepared by PNM003 were more abundant (37 kinds, 25 kinds) than those of Huniang 3.042 (35 kinds, 24 kinds). For the same strain, the flavor richness of disk fermentation was higher than that of open fermentation, and the number of musty flavor substances was lower than that of open fermentation. Thus, compared with the open fermentation, disk fermentation can significantly improve the effect of bean paste brewing, especially with PNM003 Aspergillus oryzae as the fermenting strain, the advantage is more obvious. This study provides a theoretical basis for optimizing the production process and improving the quality of bean paste.
