4种特色红茶菌发酵液感官品质、理化特性及菌群结构比较研究

目的 揭示不同红茶菌发酵液品质差异的内在原因。方法 以4种特色的红茶菌发酵液为研究对象(标记为A、B、C、D), 比较分析其在感官品质、理化特性和群落结构的差异。结果 4种红茶菌发酵液的香味、滋味差异较大, 色泽差异较小, 其中B在发酵第2 d具有独特发酵风味与茶香, 色泽橙黄, 口感清爽, 综合评分最高, 为74.2分; 4种红茶菌发酵液的菌体浓度、pH、总糖、乙酸、D-葡萄糖二酸-1,4-内酯(D-saccharic acid-1,4-lactone, DSL)及葡萄糖酸变化趋势相似, 但含量差异较大; 宏基因组测序及相关性分析表明, 4种红茶菌的优势真菌为Starmerella(暂无中文名称)和酒香酵母属(Brettanomyces), 优势细菌为驹形杆菌属(Komagataeibacter)和葡糖杆菌属(Gluconobacter), 其中Starmerella相比Brettanomyces更有利于乙酸生成, Gluconobacter相比Komagataeibacter利用碳源更高效。结论 4种红茶菌的菌群结构不同, 影响其对碳源的利用率和有机酸的形成,进而导致其发酵液感官品质上的差异。

Comparative study on sensory quality, physicochemical properties and community structure of 4 kinds of characteristic Kombucha fermentation broth

Objective To reveal the inherent reasons for the quality differences of different Kombucha fermentation broth. Methods Taking 4 kinds of Kombucha fermentation broth as the research objects (labeled A, B, C, D), the differences in sensory quality, physical and chemical characteristics and community structure were compared and analyzed. Results There were great differences in the flavor and taste of 4 kinds of Kombucha fermentation broth, but the color difference was small. Among them, B had unique fermentation flavor and tea flavor at day 2, with orange color and fresh taste, and the highest comprehensive score was 74.2. The variation trend of biomass concentration, pH, total sugar, acetic acid, D-saccharic acid-1,4-lactone (DSL) and gluconic acid of 4 kinds of Kombucha fermentation broth were similar, but there was a big difference in their content. Metagenomic sequencing showed that Starmerella and Brettanomyces were the dominant fungus of 4 kinds of Kombucha, and Komagataeibacter and Gluconobacter were the dominant bacteria. Correlation analysis showed that Starmerella was more conducive to the formation of acetic acid than Brettanomyces, and Gluconobacter was more efficient in carbon source utilization than Komagataeibacter. Conclusion The community structure difference of 4 kinds of Kombucha affect their utilization of carbon source and formation of organic acid, which lead to the differences in fermentation broth sensory quality.