Identification of characteristic flavor and microorganisms related to flavor formation in fermented common carp (Cyprinus carpio L.)

Microbial metabolism is crucial for the flavor development of traditional Suanyu. A total of 21 characteristic volatile compounds of Suanyu were identified according to GC-MS combined with GC-O analysis. HCA results indicated that the whole fermentation process could be divided into three stages: raw material (fresh), initial fermentation (0-2 week) and the late fermentation (2-4 week). Moreover, nine flavor markers in different fermentation stages were revealed using the OPLS-DA model and VIP values. Furthermore, metagenomic sequencing was used to analyze the possible formation pathways of the characteristic flavor compounds and identify the key microorganisms related to flavor formation at the gene level. The top 10 bacterial genera associated with flavor formation were Staphylococcus, Enterococcus, Vibrio, Kocuria, Lactobacillus, Macrococcus, Streptococcus, Enterobacter, Lactococcus and Pediococcus, accounting for large parts of flavor formation of fermented Suanyu. This study is helpful to elucidate the different metabolic roles of microorganisms in flavor formation during fermentation.