Abstract: In this study, the effects of salt concentration (3% (K3), 6% (K6), and 9% (K9)) on the dynamic changes in microbial communities, the accumulation of flavor compounds, and the correlation between them during sour fish fermentation were investigated using high-throughput sequencing and gas chromatography-mass spectrometry (GC-MS). The results showed that salt addition significantly regulated the structure and diversity of the microbial community. Firmicutes was the dominant phylum during fermentation, while the core dominant genera varied with salt concentration. The low-salt group (K3) exhibited higher contents of organic acids, whereas ​the total content of volatile flavor substances was significantly higher in the medium- and high-salt groups (K6 and K9) than in the low-salt group. A total of 93 volatile flavor compounds were identified, with esters, alcohols, and aldehydes being the major contributors. Characteristic flavor compounds showed salt concentration specificity. Moreover, a significant and specific correlation was observed between microorganisms and characteristic flavor substances. This study provides a theoretical basis and practical guidance for the standardization of sour fish production and the optimization of its flavor.

Key words: fermented sour fish; salt addition; microbial community; flavor quality; correlation analysis