Integrated Multi-Omics Analysis Reveals Associations Between Flavor Variation, Bacterial Communities, Metabolites, and Lipids in Commercial Dry-Cured Grass Carp

Commercial dry-cured grass carp products exhibit considerable flavor variation, but the microbial and biochemical characteristics associated with this variation remain unclear. In this study, six commercial products were comparatively characterized using electronic nose and tongue analyses, GC-MS, full-length 16S rRNA gene sequencing, metabolomics, and lipidomics. Among the six sampled products, Group F exhibited distinct aroma and taste profiles and showed a greater diversity and higher measured levels of volatile compounds on a wet-weight basis, with 1-octen-3-ol, hexanal, nonanal, and (E)-4-decenal among its prominent aroma-active compounds. Bacterial community structures differed significantly among the sampled products, with distinct species-level profiles; notably, Edwardsiella piscicida predominated in Group D, whereas Staphylococcus equorum and Staphylococcus xylosus were abundant in Groups E and F. Metabolomic and lipidomic analyses further revealed pronounced product-specific differences, particularly in organic acid- and amino acid-related metabolites and in glycerolipid and glycerophospholipid profiles. Exploratory correlations suggested potential product-level associations among bacterial taxa, lipid and metabolite profiles, and aroma-active volatiles, although none remained statistically significant after FDR correction. Overall, the results reveal coordinated differences in flavor, bacterial communities, metabolites, and lipids among the six commercial dry-cured grass carp products examined in this study and provide a compositional basis for further investigation of flavor formation.