1. High Performance Liquid Chromatography and Metabolomics Analysis of Tannase Metabolism of Gallic Acid and Gallates in Tea Leaves
- Author
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Hao-Fen Xie, Ming Zhao, Jiang Bin, Li Chongping, Yan Ma, Nian Bo, Liu Qianting, Zhang Zhengyan, Guo Tianjie, Li Hongye, Tie-Jun Ling, Jiao Wenwen, Liu Mingli, and Chen Lijiao
- Subjects
0106 biological sciences ,Ethyl gallate ,01 natural sciences ,Camellia sinensis ,Tannase ,Fungal Proteins ,chemistry.chemical_compound ,Fermented tea ,Gallic Acid ,Metabolomics ,Procyanidin B3 ,Gallic acid ,Food science ,Theaflavin ,Procyanidin B2 ,Chromatography, High Pressure Liquid ,010401 analytical chemistry ,food and beverages ,General Chemistry ,0104 chemical sciences ,Plant Leaves ,chemistry ,Fermentation ,Aspergillus niger ,Procyanidin A2 ,General Agricultural and Biological Sciences ,Carboxylic Ester Hydrolases ,010606 plant biology & botany - Abstract
Tannase (E.C. 3.1.1.20) is hypothesized to be involved in the metabolism of gallates and gallic acid (GA) in pu-erh tea fermentation. In this work, we measured tannase in Aspergillus niger fermented tea leaves and confirmed the production of fungal tannase during pu-erh tea fermentation. A decrease in catechin and theaflavin gallates and a significant increase in GA content and the relative peak areas of ethyl gallate, procyanidin A2, procyanidin B2, procyanidin B3, catechin-catechin-catechin, epiafzelechin, and epicatechin-epiafzelechin [variable importance in the projection (VIP) > 1.0, p 1.5] were observed using high performance liquid chromatography (HPLC) and metabolomics analysis of tea leaves fermented or hydrolyzed by tannase. In vitro assays showed that hydrolysis by tannase or polymerization of catechins increased the antioxidant activity of tea leaves. In summary, we identified a metabolic pathway for gallates and their derivatives in tea leaves hydrolyzed by tannase as well as associated changes in gallate and GA concentrations caused by fungal tannase during pu-erh tea fermentation.
- Published
- 2020