Analysis of Changes in Flavor Profile and Bacterial Succession During Pork Fermentation Using Multi-Omics-Based Analysis

Sour meat, a traditional fermented meat product, derives its unique attributes from the flavors developed during the fermentation process. This study systematically investigated the dynamic changes in volatile compounds and bacterial succession in pork sour meat during fermentation (0, 15, 30, and 45 days) using a combination of an electric nose (E-nose), an electric tongue (E-tongue), gas chromatography-ion mobility spectrometry (GC-IMS), gas chromatography-mass spectrometry (GC-MS), and 16S rRNA amplicon sequencing. The results showed that the E-nose and E-tongue effectively distinguished samples across fermentation stages. The pork sour meat was analyzed using GC-IMS and GC-MS, which identified 39 and 81 volatile compounds (VOCs), respectively, primarily esters, alcohols, and aldehydes, with esters being most abundant after 45 days of fermentation. A total of 18 and 25 volatile compounds, respectively, were identified by GC-IMS and GC-MS as differential VOCs (p < 0.05, VIP > 1) of the pork sour meat. alpha-diversity increased in both species' richness and diversity over the course of fermentation, while beta-diversity analysis further differentiated samples across stages. Firmicutes dominated the bacterial community, with Staphylococcus, Lactobacillus, and Weissella as the main genera. Pearson correlation analysis revealed distinct associations between bacteria and volatiles: Staphylococcus was positively associated with butyl acetate-D, ethyl acetate, isoamyl acetate, dihydroactinidiolide, and (E)-2-heptenal, while Lactobacillus and Weissella were positively associated with acetic acid. Additionally, Weissella showed positive correlations with eight volatile compounds: acetic acid, nonanal, benzyl alcohol, ethyl crotonate, isoamyl acetate, dihydroactinidiolide, octanal, and ethyl acetate. This study provides a comprehensive understanding of volatile compound evolution and bacterial succession in pork sour meat, thereby offering a scientific basis for understanding and regulating its flavor quality.