Impact of KCl-divalent salt synergistic substitution on protease activity and volatile flavor profile in sodium-reduced sour meat.

Sour meat is a traditional Chinese fermented product valued for its unique flavor, which is achieved through high-salt processing. Nevertheless, the consequent excessive sodium intake increases the health risks. This study developed a sodium-reduced sour meat strategy by replacing 40% of sodium chloride (NaCl) with potassium chloride (KCl) in combination with divalent salts, namely calcium chloride (CaCl2) or magnesium chloride (MgCl2). The substitution differentially regulated endogenous proteases: KCl-MgCl2 enhanced cathepsin B/L and dipeptidyl peptidase IV activities, increasing volatile compounds; KCl-CaCl2 elevated dipeptidyl peptidase I and alanyl aminopeptidase, promoting TCA-soluble peptides and amino acids. PLS-DA identified key flavor compounds (VIP >1), and correlations linked protease activities to flavor formation. The strategy enables targeted enzymatic regulation for producing healthier sour meat with improved flavor.