Strain-dependent metabolic remodelling by indigenous yeasts from fermented sausages enhances saltiness responses in a low-NaCl meat slurry model.

This study evaluated five indigenous yeasts (Candida zeylanoides DQ7, Pichia kudriavzevii MDJ1, Torulaspora delbrueckii HG7, Debaryomyces hansenii SH4, and Yarrowia lipolytica SH1) for saltiness-related flavour modulation in a low-NaCl meat slurry model. All inoculated yeasts proliferated and enhanced saltiness, umami, and richness to varying degrees. Strain-specific metabolic signatures were observed, including nucleotide turnover in T. delbrueckii HG7, peptide/nitrogen remodelling in P. kudriavzevii MDJ1, oligopeptide enrichment in Y. lipolytica SH1, lipid-derived transformation in C. zeylanoides DQ7, and integrated amino acid, nucleotide, and organic acid redistribution in D. hansenii SH4. Yeast inoculation shifted volatile profiles from aldehyde-dominated oxidative notes towards fermentation-associated alcohols, esters, ketones, furans, and sulphur-containing compounds. Correlation analysis identified 59 non-volatile metabolites and 30 volatiles positively associated with saltiness, umami, and richness, particularly furans and sulphur compounds. Integrated pathway mapping suggested a multi-module metabolic network in which nucleotide turnover, amino acid redistribution, lipid-derived volatiles, and glutathione-mediated redox regulation were associated with saltiness enhancement. These findings support taste-aroma metabolic coupling as a basis for yeast-assisted sodium reduction in fermented meats.