Modulation of flavour perception under sodium-reduced conditions: A sensory-metabolic interaction framework driven by Debaryomyces hansenii SH4 and KCl.

This study reconstructs salt-associated flavour in sodium-reduced fermented sausages by integrating ionic substitution (KCl) and yeast-based biotransformation (Debaryomyces hansenii SH4). Comprehensive analysis integrating non-volatile and volatile compound profiling, sensory evaluation, and electronic sensing (E-tongue and E-nose) was employed to decode the underlying mechanisms. The combined KCl and D. hansenii treatment (1.75 % NaCl +0.75 % KCl + D. hansenii SH4) significantly elevated perceived saltiness and umami intensity, exceeding even the full-salt control, while effectively mitigating bitterness and astringency. These effects were supported by a 4-fold increase in equivalent umami concentration, expanded taste-active compound coverage (taste activity value >1), and odour-active ester enrichment (odour activity value >1). Mechanistically, KCl modulated ionic pathways while D. hansenii SH4 catalysed the biosynthesis of Glu, Asp, 5'-nucleotides, and esters-collectively amplifying cross-modal flavour cues. This study provides mechanistic insights and technical pathways for developing healthier fermented meats without sacrificing sensory appeal.