High Performance Liquid Chromatography and Metabolomics Analysis of Tannase Metabolism of Gallic Acid and Gallates in Tea Leaves

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 < 0.05, and fold change (FC) > 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.

Impact of Various Microbial-Fermented Methods on the Chemical Profile of Dark Tea Using a Single Raw Tea Material

“…Tannase ( E.C. 3.1.1.20 ) secreted by microorganisms is responsible for hydrolyzing gallates into GA in dark teas during microbial fermentation. ,, This could explain the abundant GA in CDTs. In another study, caffeine levels was found to increase significantly after the microbial fermentation of PU tea, and guanine deaminase was reported to have an important relation to the mechanism underlying the increased caffeine content .…”

“…A total of 569 metabolites were identified by comparing with standards from the MetWare selfconstructed metabolite database and MS/MS spectrum information from published databases (MassBank, KNAp-SAcK, HMDB, and METLIN). All the identified metabolites, as listed in detail in Table S1, were classified into 10 subgroups pointing to their metabolic pathways, including flavonoids (185), phenolic acids (84), amino acids and derivatives (62), lipids (54), others (50), nucleotides and derivatives (42), organic acids (31), alkaloids (19), tannins (19), and lignans and coumarins (12). Successively, all metabolites were subjected to multivariate statistical analysis.…”

Comparison of fungal communities and nonvolatile flavor components in black Huangjiu formed using different inoculation fermentation methods

“…In this study, SF3 and CK3 were selected and delivered to the company for determination the nVFCs of samples by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis (Shanghai Meiji Biomedical Technology Co., Ltd., Shanghai, China). The following works were accomplished according to our recent study, which included the extraction of nVFCs, UPLC separation, ESI-MS/MS monitoring, and data processing (Liu et al, 2020). Identification of nVFC was dependent on the primary and secondary MS data, annotated against an in-house database, or the matches of both retention times and MS data to some standard compounds in Metware.…”

You Are What You Eat: Application of Metabolomics Approaches to Advance Nutrition Research

“…Metabolomics employs different analytical platforms including high-performance liquid chromatography (HPLC) [22][23][24][25][26][27], Fourier transformed infrared (FT-IR) spectroscopy [28][29][30][31], mass spectrometry (MS) [32][33][34][35] and nuclear magnetic resonance (NMR) spectroscopy [36][37][38][39][40][41][42].…”