Multi-omics-based insights into the microbial community composition and quality characteristic differentiation...

To uncover the microbial underpinnings of quality and flavor differences between Xuanwei ham (XWH) and Iberian ham (IRH), this study integrated high-throughput sequencing with metabolomics and volatilomics to establish microbiota-metabolite-flavor linkages. Physicochemical characterization revealed that XWH showed higher moisture, water activity, and salt content, whereas IRH had higher fat and protein. These matrix differences imposed selective pressures on microbial colonization. The IRH surface exhibited higher bacterial diversity, while the XWH interior showed higher bacterial diversity; XWH also had higher fungal diversity overall. Staphylococcus dominated both hams, whereas Debaryomyces yeasts were enriched inside hams. Metabolomics identified 312 differential metabolites, mainly enriched in amino acid pathways. XWH was enriched in sweet-tasting amino acids and short-chain fatty acids, while IRH featured glutamic acid, polyunsaturated fatty acids, and phenolic acid esters. Volatilomics revealed 24 key differential odorants: IRH was enriched in medium-to-long chain ketones and aldehydes from lipid oxidation, and XWH accumulated short-chain ketones and alcohols from carbohydrate fermentation. Correlation analysis showed that Staphylococcus and Debaryomyces were strongly positively correlated with most differential metabolites and key volatiles, indicating their driving role in shaping the metabolic landscape. Tight positive correlations between flavor compounds and their precursor metabolites further support a microbiota-mediated cascade from substrate degradation to volatile generation. These findings demonstrate that region-specific processing conditions sculpt distinct microbial consortia and that core microbiota are primary drivers of quality differentiation. This work provides a mechanistic framework for flavor-directed regulation and starter culture design in dry-ham production.