Flavoromics, sensory evaluation, metagenomics and untargeted metabolomics analysis of fermented tofu sheets from different regions of China

Fermented tofu sheets, a traditional Chinese soybean product, are renowned for their distinctive flavors, which vary significantly across regions. This study investigates the flavor attributes and microbial metabolic differences of fermented tofu sheets from four regions in China (Anyang in Henan Province (HN), Suizhou in Hubei Province (HB), Shaoxing in Zhejiang Province (SX), and Yibin in Sichuan Province (SC)) using a comprehensive approach integrating flavoromics, sensory evaluation, metagenomics, and untargeted metabolomics. The results identified 17 core flavor compounds in HN and HB, 15 in SX, and 11 in SC, with eight common across all samples. Significant regional differences were observed in the microbial community structures of the fermented tofu sheets. Untargeted metabolomics identified 857 differential metabolites, with key pathways including caffeine metabolism, alanine, aspartate, and glutamate metabolism, tryptophan metabolism, the pentose phosphate pathway, and purine metabolism. These metabolic variations contribute to the distinct flavor profiles of fermented tofu sheets from different regions. This study provides valuable insights into enhancing the fermentation quality of fermented tofu sheets.