Effect of the bacterial community on the volatile flavour profile of a Chinese fermented condiment - Red sour soup - During fermentation.

Red sour soup (RSS) is a traditional fermented seasoning used by people in Guizhou Province, China. The volatile compounds were detected by gas chromatography ion mobility spectrometry (GC-IMS), while the bacterial community compositions were revealed by 16S sequencing. A total of 70 volatile substances were assessed, and esters, terpenes, and alcohols played a dominant role in RSS. Lactic acid bacteria (LAB) were dominant in the microbial community. During fermentation, multiple volatile flavour substances and various LAB were mainly derived from the secondary fermentation stage. The core bacteria with an important influence on volatile flavour substances were analysed by the Mantel test, identifying Bacteroides, Lactobacillus, Lactococcus, Enterobacteriaceae, Pantoea, Clostridium, Enterobacter, unclassified genera, Caproiciproducens, Nitriliruptoraceae, Halomonas, Bradyrhizobium, Pediococcus, Caulobacteraceae, Weissella, Ligilactobacillus, and Levilactobacillus and et al.. This study provides us with useful information about flavour-generating bacteria among RSS fermentation periods. The abundances of these bacteria may be controlled to enrich the desired flavour metabolites while eliminating unwanted metabolites.