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.
Original language | English |
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Article number | 125895 |
Pages (from-to) | 125895 |
Journal | Food Chemistry |
Volume | 311 |
DOIs | |
Publication status | Published - 1 May 2020 |
Externally published | Yes |
Keywords
- (−)-Epigallocatechin gallate
- Camellia assamica
- Flavan-3-ols
- Metabolomics
- Pile-fermentation
- α-glucosidase