Flavor Changes in Reduced-Salt Sour Meat During Synergistic Fermentation with Salt Substitutes and Lactobacillus plantarum SJ-4: Based on Microbial Community and Metabolomic Analyses

This study investigated the effects of Lactiplantibacillus plantarum SJ-4 inoculation, partial replacement of sodium chloride (NaCl) with potassium chloride (KCl) and calcium ascorbate (CaA), and their combined treatment on the fermentation quality of fermented pork sour meat. Microbial community and metabolomic analyses were further integrated to explore the potential mechanisms related to flavor formation and quality changes. The combined treatment (LP + K-Ca group) improved the flavor profile, increased the contents of volatile compounds and free amino acids, reduced several undesirable flavor-related compounds, and contributed to better fermentation quality. Compared with the control group (C), total free amino acids and essential amino acids in the LP + K-Ca group increased by 4.95% and 22.71%, respectively, while the contents of undesirable compounds such as 2-nonenal, hypoxanthine, and ketones decreased by 73.65%, 73.40%, and 9.58%, respectively. Key flavor-related microorganisms included Macrococcus, Staphylococcus, and Lactiplantibacillus. These microorganisms are intricately linked to metabolic products such as amino acids, fatty acids, and organic acids, which may provide important precursors for volatile flavor formation. Overall, the combined treatment of 40% NaCl replacement with 24% KCl and 16% CaA, together with 2% L. plantarum SJ-4 inoculation, showed potential for improving flavor formation and fermentation quality in salt-reduced sour meat based on partial NaCl replacement.