Temporal and spatial changes in microbial communities and their correlation with volatile aroma compounds during the fermentation of Mucor racemosus sufu

Summary Sufu, a traditional Chinese fermented soybean food, had its flavour and quality influenced by the specific strains and fermentation environment. To investigate how microbial community succession affects the volatile aroma substances of Mucor racemosus sufu during fermentation, the microbial community structure using high-throughput sequencing (HTS) technology was analysed. Additionally, volatile flavour compounds using solid-phase microextraction gas chromatography mass spectrometry (SPME-GC–MS) were detected. Throughout the pre-fermentation, salting, and post-fermentation stages, the changes in the microbial communities over time and space due to environmental variations were observed. The colony compositions at the phylum and genus levels were also analysed. The results revealed that Proteobacteria and Actinobacteria were the dominant bacterial phyla in the final fermented product. Furthermore, several microorganisms associated with flavour substances were identified, such as Lactobacillus , Pseudomonas , Wescheria , Hyphomyces , Candida , and Pichia . These microorganisms primarily influenced the synthesis of alcohols and acids, contributing to the overall flavour profile of the sufu. In the analysis of the final product, it identified fifty-four volatile flavour compounds, including alcohols, esters, phenolic acids, aldehydes, ketones, ether, alkenes, and other compounds. These findings have important implications for isolating specific strains, enhancing flavour, and providing a solid foundation for optimising and ensuring the quality of sufu.