Single-starter replacement strategy: Insights from untargeted metabolomics and GC-MS into the role of Staphylococcus vitulinus protease in promoting protein hydrolysis and flavor enhancement in Harbin dry sausage.

This study proposes an alternative strategy using Staphylococcus vitulinus protease as the sole fermentative starter in Harbin dry sausages and explores its mechanism. S. vitulinus protease promoted the accumulation of low-molecular-weight proteins (7-20 kDa) and correspondingly increased the content of α-helix and random coil in the secondary structure. The addition of the protease significantly increased peptide and free amino acid (FAA) contents (p < 0.05), enhancing FAA taste activity values. Metabolomics revealed elevated levels of taste peptides, amino acids and derivatives, and unsaturated fatty acids. Simultaneously, volatile compounds including aldehydes, esters, ketones, and acids were enhanced. The addition of S. vitulinus protease promoted protein digestion and absorption, aminoacyl-tRNA biosynthesis, and biosynthesis of amino acids. Molecular docking analysis indicated that hydrogen bonding is the primary interaction between the protease and myosin heavy chain as well as phosphorylase.