Dynamic changes of microbiota and metabolite of traditional Hainan dregs vinegar during fermentation based on metagenomics and metabolomics.

Hainan dregs vinegar (HNDV) is a traditional fermented food in China that is renowned for its unique flavor. HNDV is one of the most popular vinegars in Southeast Asia. However, research on the microorganisms and characteristic metabolites specific to HNDV is lacking. This study investigated the changes in microbial succession, volatile flavor compounds and characteristic non-volatile flavor compounds during HNDV fermentation based on metagenomics and metabolomics. The predominant microbial genera were Lactococcus, Limosilactobacillus, Lactiplantibacillus, and Saccharomyces. Unlike traditional vinegar, l-lactic acid was identified as the primary organic acid in HNDV. Noteworthy flavor compounds specific to HNDV included 3-methylthiopropanol and dl-phenylalanine. Significant associations were observed between six predominant microorganisms and six characteristic volatile flavor compounds, as well as seven characteristic non-volatile flavor compounds. The present results contribute to the development of starter cultures and the enhancement of HNDV quality.