Zhang Huan, Liu Yong-Zhong, Xu Wen-Can, Chen Wen-Jun, Wu Shuang, Huang You-Yi
Ministry of Education Key Laboratory of Horticultural Plant Biology, and Tea Science Department of Horticulture and Forestry Science College, Huazhong Agricultural University, Wuhan City 430070, China.
Ministry of Education Key Laboratory of Horticultural Plant Biology, and Fruit Science Department of Horticulture and Forestry Science College, Huazhong Agricultural University, Wuhan City 430070, China.
J Agric Food Chem. 2020 Nov 25;68(47):13751-13759. doi: 10.1021/acs.jafc.0c06187. Epub 2020 Nov 9.
Gallic acid (GA) is an important active ingredient for its pharmacological activities. High levels of GA in tea can be obtained by anaerobic fermentation, but its mechanism is still unclear. Here, the profiles of metabolites and microbiomes in pickled tea were analyzed. The results showed that GA of pickled tea increased to 24.26 mg/g at 18 d after anaerobic fermentation, which was accompanied by the reducing levels of epicatechin gallate (ECG), epiafzelechin-3--gallate (EAG), and 7-galloylcatechin (7-GC) and the increasing relative abundances of and other six bacterial genera. However, epigallocatechin gallate (EGCG) was basically stable during the whole fermentation process. These results suggested that EGCG contributes little to the GA formation during anaerobic fermentation, but ECG, EAG, and 7-GC should be the key precursors to form GA; moreover, bacteria, especially may be responsible for their bioconversion. It will establish an effective way to increase GA in tea production.
没食子酸（GA）因其药理活性而成为一种重要的活性成分。通过厌氧发酵可使茶叶中获得高水平的GA，但其机制仍不清楚。在此，对腌茶中的代谢物和微生物群落进行了分析。结果表明，厌氧发酵18 d后，腌茶中的GA增加至24.26 mg/g，同时伴随着表没食子儿茶素没食子酸酯（ECG）、表阿夫儿茶素-3-没食子酸酯（EAG）和7-没食子酰儿茶素（7-GC）含量的降低以及 属和其他六个细菌属相对丰度的增加。然而，表没食子儿茶素没食子酸酯（EGCG）在整个发酵过程中基本稳定。这些结果表明，EGCG在厌氧发酵过程中对GA形成的贡献很小，但ECG、EAG和7-GC应该是形成GA的关键前体；此外，细菌，尤其是 属可能负责它们的生物转化。这将为茶叶生产中提高GA建立一种有效的方法。
