Unveiling flavor formation and variation in fermented vinasse grass carp based on the dynamic correlation of microbiota with metabolites by multi-omics and bioinformatics approaches.

This study investigated the succession of metabolites and microorganisms during vinasse grass carp fermentation and their relationships. A total of 160 volatile compounds (VCs) were identified, among which 17 were recognized as key VCs (OAV > 1 and VIP > 1), including ethyl hexanoate, isopentyl hexanoate, ethyl palmitate, ethyl linoleate, ethyl oleate, ethyl stearate, eugenol, methionol, phenylethyl alcohol, 4-methyl-5-thiazoleethanol, isoamyl alcohol, 1-octen-3-ol, 2,3-butanedione, hexanal, (E)-2-octenal, nonanal, and β-caryophyllene. Significant differences in microbial community composition were observed throughout fermentation. Driven by moisture content, reducing sugar, and total acidity, Staphylococcus and Saccharomyces remained dominant microbial, Macrococcus and Rhizopus decreased, while Lactobacillus, Bacteroides, Wickerhamomyces, and Aspergillus gradually increased as fermentation processed. Metabolic analysis revealed that microbiota affect vinasse fish flavor by regulating lipid, carbohydrate, and amino acid metabolism, particularly alpha-linolenic acid and arachidonic acid metabolic pathways during early-to-mid fermentation stages. This study offers a theoretical foundation for targeted flavor regulation in vinasse fish.