Study on volatile metabolites and microbial community in the fermentation process of black tea (Jiuqu hongmei tea)

Jiuqu hongmei tea (JQHM tea), unique to Zhejiang Province, China, is celebrated for its vibrant, delightful taste and distinctive flavor profile. This research explored the relationship between the tea's characteristic flavor during fermentation and the dynamics of microbial communities. Volatile organic compounds (VOCs) were analyzed using Headspace Solid-Phase Microextraction coupled with Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS) at three key stages: machine kneading (MK, 0.5 h), primary fermentation (F1, 1.5 h), and secondary fermentation (F2, 3 h). Concurrently, microbial communities were characterized through high-throughput sequencing. The study identified 12 significant VOCs and pinpointed 10 core bacterial and 9 core fungal genera. These findings revealed the intricate changes in aroma compounds and microbial populations throughout JQHM tea's fermentation process, highlighting the interplay between key aroma compounds and principal microbial genera. This knowledge provided a crucial theoretical foundation for refining the tea's processing stages and enhancing its flavor quality.