Untargeted and targeted metabolomics reveal the chemical characteristic of pu-erh tea (Camellia assamica) during pile-fermentation. (1st May 2020)

• Record Type: Journal Article
• Authors: Long, Piaopiao; Wen, Mingchun; Granato, Daniel; Zhou, Jie; Wu, You; Hou, Yan; Zhang, Liang
• Is Part Of: Food chemistry. Volume 311(2020)
• Publication Date: 2020-05-01
• Subjects: Camellia assamica -- Pile-fermentation -- Metabolomics -- α-glucosidase -- (−)-Epigallocatechin gallate -- Flavan-3-ols; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2019.125895
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: Post-fermentation highly decreased the flavonol O-glycosides' contents. Inhibitory effects on α-glucosidase and α-amylase were decreased after pile-fermentation. Metabolomics revealed astringent compounds' contents were decreased. Abstract: Pile-fermentation is the most important process of producing ripened pu-erh tea. To study the chemical changes of tea leaves during pile-fermentation (PF), liquid chromatography coupled with tandem mass spectrometry (LC-MS) was used. Untargeted metabolomics analysis revealed that the first stage of PF is crucial in transforming the original secondary metabolites, whereas the contents of flavan-3-ols and gallic acid were decreased after long-term PF. Targeted metabolomics analysis indicated that the levels of puerins (N-ethyl-2-pyrrolidinone substituted gallocatechin and catechin) were significant increased after the first stage of PF, but after long-term PF the levels of flavonol glycosides, procyanidins and galloylated flavan-3-ols were significantly decreased. Accordingly, long-term PF also decreased the inhibition of α-amylase and α-glucosidase activities of the extracts. As a conclusion, pile-fermentation is an important step of changing the polyphenols and bioactivities of pu-erh tea.