Changes of microbial community diversity and flavor substances during fermentation of Bashang Suancai in different months

The fluctuations in natural temperature during different months have a significant impact on the naturally fermented Bashang Suancai. The changes of microbial community and volatile flavor compounds (VFCs) of Suancai in different fermentation months were examined by Illumina NovaSeq high-throughput sequencing and headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). At the phylum level, Firmicutes , Proteobacteria and Cyanobacteria were the dominant bacteria. At the genus level, the dominant bacteria were mainly Lactiplantibacillus , Cyanobacteriales , Vibrio and Weissella . The natural fermentation in different months also significantly altered the VFCs in Suancai. The Suancai fermented in July appeared to contain a greater total number of VFCs. 3 compounds (VIP> 1.0) were deemed significantly associated with the fermentation process, which were all analogs of isothiocyanates. Spearman correlation analysis revealed that Lactiplantibacillus , Pediococcus , Enterobacter , Weissella and Vibrio were highly correlated with the flavor profile of pickles. Our study showed that the fermentation of Bashang Suancai in warmer months (July and August) was more conducive for the accumulation of beneficial bacteria, and it also resulted in the formation of more flavor compounds. This study provided strong theoretical support for the pickling of high-quality Suancai and established a scientific foundation for promoting the commercialization for it.