Astral-based DIA proteomics explored the flavor enhancement mechanism of Chinese traditional smoked bacon by staphylococcal co-fermentation

The proteolysis pattern during mixed fermentation of Staphylococcus cohnii WX-M8 and S. saprophyticus MY-A10 on Chinese bacon was still unknown. In this study, the changing laws of protein degradation products during staphylococcal mixed fermentation were analyzed, followed by an investigation of endogenous enzymes and cellular components, and finally an examination of flavor profiles. Results indicated that mixed fermentation improved protein degradation and promoted the production of peptides and free amino acids (FAAs). Proteolysis of S. saprophyticus MY-A10 was non-specific, and it promoted protein degradation by cooperating with cathepsin L1. S. cohnii WX-M8 was specific and acted mainly with calpain-3 in the thin filament. The fulfillment of S. cohnii WX-M8 function was enhanced in the presence of S. saprophyticus MY-A10. Mixed fermentation showed synergism with endogenous peptidases in degrading peptides to small-molecule peptides or FAAs and complementarity with endogenous dehydrogenases in converting FAAs to volatile organic compounds (VOCs).