Rice wine lees coating enhances proteolysis and umami development in Jinhua ham during ripening

This study investigated the effects of rice wine lees coating on proteolysis, peptide formation, amino acid metabolism, and taste development in Jinhua ham during ripening. Three traditional lees types (Fujian red yeast rice lees (RL), Shengzhou yellow wine lees (YL1), and Ningbo pressed lees (YL2)) were applied to the ham surface, and their biochemical and sensory impacts were systematically evaluated. Lees treatment significantly enhanced acid protease activity, accelerated the degradation of sarcoplasmic and myofibrillar proteins, and increased total volatile basic nitrogen levels within a safe range. Peptidomic profiling revealed a substantial rise in peptide number and diversity, particularly in YL1-treated samples, with enrichment of taste-active peptides such as SSI, RCA, LDI, and HLAA. Free amino acid analysis confirmed higher concentrations of umami-related amino acids (Glu, Arg, Lys) in lees-treated groups, consistent with the elevated proteolytic activity. Electronic tongue and sensory evaluations demonstrated intensified umami and sweetness perceptions, accompanied by enhanced overall taste complexity and mild alcoholic aroma. The results indicate that rice wine lees effectively promote proteolysis and the formation of taste-active compounds, providing a natural and sustainable strategy to improve the sensory quality and flavor richness of traditional dry-cured hams.