Correlation analysis between volatile flavor compounds and microbial succession of Lithocarpus litseifolius [Hance] Chun (L. litseifolius) kombucha during fermentation

Abstract

Llitseifolius with various health benefits, which has been approved as a new food material in China since 2017, can be a promising substrate for kombucha. In this study, kombucha using L. litseifolius (L. Komb) as sole raw material was successfully prepared by inoculating a symbiotic culture of bacteria and yeast (SCOBY). The alterations in flavor compounds and microbial communities, as well as their potential correlations during fermentation were investigated. A total of 113 volatile flavor compounds (VFCs) were identified using headspace-solid phase microextraction-gas chromatography mass spectrometry (HS-SPME-GC-MS). Among them, alcohols and acids accounted for a larger proportion. During fermentation, the contents of ethanol, 3-methyl-1-butanol, phenylethyl Alcohol, and acetic acid was 142.73–290.92, 108.59–371.74, 36.09–184.80, and 255.91–685.82 μg/L, respectively. The results of high-throughput sequencing analysis indicated that Komagataeibacter, Gluconobacter, and Ralstonia were the dominant bacterial genera, while Zygosaccharomyces was the predominant fungal genus. The Spearman correlation coefficient demonstrated medium-high correlations (|ρ| > 0.6) between VFCs and 13 core microbes. The primary alcohols, acids, and esters in L. Komb exhibited strong associations with specific microorganisms, including Komagataeibacter, Gluconobacter, Ralstonia, Stenotrophomonas, and Starmerella. It contributes to understanding the role of core microorganisms in the overall flavor formation of L. Komb, providing valuable reference for practical flavor promotion of kombucha.