Microbial diversity and chemical property analyses of sufu products with different producing regions and dressing flavors

Sufu is a cheese-like product fermented with soybean curd in China, widely consumed for its unique nutritional and flavor properties. To investigate the associations among microbial communities, chemical properties, producing regions and dressing flavors of sufu, the high-throughput sequencing for 16 sufu products from different regions based on the bacterial 16S rRNA and fungal internal transcribed spacer 2 gene was performed. A sum of 368 bacterial genera and 299 fungal genera were identified. The fungal microflora in sufu samples contained many symbiont fungi of soybean. Aspergillus and Actinomucor were abundant in the sufu products as hydrolase-producing genera. The bacterial diversity result showed that lactic acid bacteria (LAB) were very abundant in all these sufu products and the Lactococcus was the most abundant genus. According to the principal coordinate analysis and hierarchical clustering analysis, the bacterial communities of sufu samples could be generally clustered into the LAB clade and Bacillus clade. Moreover, the fungal communities of sufu samples from eastern China could be generally clustered into one group, while the dressing flavor of sufu samples during post-fermentation was not a major factor for microbial communities shaping. This study could potentially serve as a reference for a rational design of microbial communities to improve the sufu quality.