Characterization and Correlation of Microbial Communities and Volatile Flavor Compounds in Cabbage Kimchi

In order to reveal the changes in microbial communities and volatile flavor compounds during the fermentation process of cabbage kimchi and the correlation between them, high-throughput sequencing (NGS) and headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME/GC-MS) were used to study the microbial diversity and volatile flavor components of kimchi on Days 1, 3, 5, 7, 9, and 10 of fermentation. The correlation between microbial diversity and volatile flavor compounds was also analyzed in detail. The results showed that, in the microbial analysis of kimchi, 115 bacterial genera were identified, including <i>Lactiplantibacillus</i>, <i>Bacillus</i>, <i>Staphylococcus</i>, and <i>Tetragenococcus</i>, among others. The average relative abundance of <i>Lactiplantibacillus</i> was 23.44%, making it the most predominant bacterial genus in kimchi. Additionally, 176 fungal genera were identified, including <i>Membranomyces</i>, <i>Aureobasidium</i>, <i>Scedosporium</i>, <i>Neomicrosphaeropsis</i>, <i>Phallus</i>, and <i>Saccharomycopsis</i>, among others. <i>Membranomyces</i> had the highest average relative abundance at 85.63%, making it the most abundant fungal genus in kimchi. In the analysis of volatile flavor compounds in kimchi, 102 volatile compounds were detected, including methanethiol, linalool, and α-pinene, etc. The average relative content of acetic acid was 6.76%, and the average relative content of dimethyl disulfide was 7.32%, making them the highest among the volatile flavor compounds detected. Alcohols and sulfur-containing compounds were the main volatile flavor compounds. According to the correlation analysis using SPSS, 18 bacterial genera showed a strong positive correlation with volatile flavor compounds, and 15 fungal genera showed a strong positive correlation, with correlation coefficients > 0.9. The correlation analysis indicated that <i>Lactiplantibacillus</i>, <i>Bacillus</i>, <i>Staphylococcus</i>, and <i>Tetragenococcus</i> are the core bacterial genera responsible for producing key volatile flavor compounds in kimchi, while <i>Membranomyces</i>, <i>Aureobasidium</i>, <i>Scedosporium</i>, <i>Neomicrosphaeropsis</i>, <i>Phallus</i>, and <i>Saccharomycopsis</i> are the core fungal genera.