Bacterial community dynamics associated with proteolysis, protein oxidation, and quality formation across muscle...

This study elucidated the roles of bacterial community dynamics, proteolysis and protein oxidation in the quality formation of Xuanwei ham by comparing the semimembranosus (SM) and biceps femoris (BF) muscles across six processing stages. Moisture content and water activity decreased significantly (P < 0.05) during processing, accompanied by intensified protein oxidation, as evidenced by a decrease in reactive sulphydryl groups and an increase in both carbonyl content and surface hydrophobicity. SDS-PAGE analysis confirmed substantial degradation of myofibrillar proteins. The total free amino acid content was higher in the BF than in the SM and was closely associated with the accumulation of specific amino acids, such as glutamic acid and alanine. The bacterial community exhibited distinct successional patterns that varied with processing stage and anatomical location. Firmicutes and Proteobacteria were the dominant phyla, with Staphylococcus, Macrococcus and Weissella identified as the predominant genera. Mantel analysis revealed significant associations between dominant bacterial communities, particularly Staphylococcus and Weissella, and flavour precursor accumulation as well as texture-related changes in Xuanwei ham. These findings provide a comprehensive spatiotemporal characterization of bacterial succession, proteolysis, protein oxidation, and quality-related biochemical changes during Xuanwei ham processing, thereby establishing a theoretical basis for its quality regulation.