Characterization of catechins, theaflavins, and flavonols by leaf processing step in green and black teas (Camellia sinensis) using UPLC-DAD-QToF/MS

Abstract

Most previous studies have been focused on the variation of tea chemical composition by fermentative processes as well as different cultivars and regions. The detailed changes of flavonoid profiles were described for the first time by each processing step of green and black tea leaves in this study. A total of 24 flavonoid derivatives including catechins, theaflavins, and flavonols were separated and identified from the tea samples based on UPLC-DAD-QToF/MS data and constructed library. Among these, the fragmentation pathway of theaflavins was proposed specifically in positive ionization mode for structural interpretation. During leaf processing, the individual flavonols were changed as diverse patterns according to their aglycone types and glycosylated forms, but their total content showed a slight difference. EGCG and ECG were increased after roasting approximately twofold higher than that of fresh leaves (EGCG, 2709.5 →6085.6; ECG, 1548.0 →2318.2 mg/100 g dry weight, respectively) in green tea while considerably decreased their contents due to oxidation and conversion to theaflavins after fermentation during black tea processing. Especially, the drying steps also found to be factor to influence positively to increase the flavonoid contents in both tea processing. Therefore, this result indicated that detailed conditions of each processing step played important roles in changing the flavonoid profiles from tea leaves.

Changes in major catechins, caffeine, and antioxidant activity during CTC processing of black tea from North East India

“…The behavior of chemical changes during CTC processing of black tea from NE Indian tea cultivar is similar to cultivars from other regions of the world. 37,38 For instance, similar to the present study, Lee et al 37 observed a near complete degradation of major catechins during the processing of black tea. However, the extent of changes in TP contents was different.…”

Chemometric Analysis of Extracts and Fractions from Green, Oxidized, and Microbial Fermented Teas and Their Correlation to Potential Antioxidant and Anticancer Effects

“…The relative content of 10 flavonol glycosides in the four processed tea extracts differed from that in GTE ( Table S2 ). Myricetin glycosides completely disappeared in BTE and CTE, presumably due to intrinsic enzymatic reaction according to a previous report [ 31 ]. The contents of apigenin glycoside (peak g), kaempferol glycoside (peak j), and quercetin glycoside (peak f) in MTE and PTE were increased because of their microbial transformation by detaching the monoglycosyl (arabinose or glucose) moieties of peak a, peak i, and peak d or e, respectively.…”

Coumaroyl Flavonol Glycosides and More in Marketed Green Teas: An Intrinsic Value beyond Much-Lauded Catechins

“…The TOF-MS/MS spectrum of compound 29 was in agreement with the presence of a kaempferol trisaccharide. Accordingly, previous studies suggested the occurrence of a kaempferol triglycoside in which the saccharide moiety consisted of (3"-O-galactosyl)rutinose [46]. The content of these molecules was more abundant in the TeaMTC sample.…”

“…The content of these molecules was more abundant in the TeaMTC sample. Recent studies have also found triglycosides of myricetin and have defined their disappearance as a consequence of the fermentation and oxidation processes [46]. Recently, the obtainment of a flavonol glycosides-rich extract named FLG was optimized from an aqueous green tea extract after tannase treatment [47].…”