The Volatile Flavor Substances, Microbial Diversity, and Their Potential Correlations of Inner and Surface Areas within Chinese Qingcheng Mountain Traditional Bacon

The objective of this study was to explore the microbial diversity, volatile flavor substances, and their potential correlations in inner and surface Chinese Qingcheng Mountain traditional bacon (CQTB). The results showed that there were 39 volatile flavor substances in inner and surface CQTB detected by headspace solid-phase microextraction and gas chromatography-mass spectrometry (HS-SPME-GC-MS). Moreover, significant differences in volatile flavor substances between the inner and surface CQTB were observed. Sixteen key volatile flavor substances were screened (OAV > 1), including guaiacol, nonanal, ethyl isovalerate, and others. High-throughput sequencing (HTS) result indicated that Firmicutes, Proteobacteria, and Actinobacteria were the predominant bacterial phyla, and Ascomycota and Mucoromycota were the predominant fungal phyla. Staphylococcus, Psychrobacter, and Brochothrix were the predominant bacteria, and Debaryomyces, Penicillium, and Mucor were the predominant fungal genera. Spearman correlation coefficient analysis suggested that Apiotrichum and Lactobacillus were closely and positively correlated with the formation of key phenol compounds. The present work demonstrates the microbial diversity and related volatile flavor substances and their potential correlations in CQTB and provides a theoretical basis for the development of microbial starter culture and green processing of CQTB.