Evaluation of significant pigmets in green teas of different origin

Abstract

This work monitors flavonoid pigments (theaflavins and thearubigins), and chlorophyll in green teas from different growing regions (India, China, Russia, Vietnam). These pigments affect the quality of the finished tea infusion and their quantity is affected by the way of tea processing (fermentation). 15 samples of green loose teas were selected for the analysis. The content of these pigments was determined using UV-Vis spectrophotometry, the concentration of flavonoid pigments was measured at a wavelength of 665 nm (theaflavins) and 825 nm (thearubigins). Concentration of flavonoid pigments was determined using the standard conversion coefficients, which are 38.7 for TRs and 1.4 for TFs. Chlorophyll concentration was measured at 642.5 and 660 nm. Chlorophyll concentration was determined by the conversion using international standard conversion coefficients and calculation of linear regressions. The results were statistically processed and evaluated in the program of UNISTAT version 5.6. The total amount of chlorophyll ranged from 0.20 to 1.33 mg/L of tea. Concentrations of theaflavin ranged from 0.15 to 0.66 g/100 g of tea and TRs from 2.00 to 11.15 g/100 g of tea. The results showed that the amount of theaflavins, thearubigins and chlorophyll in green teas varied (P <0,05), especially in teas from lowlands in Vietnam and Krasnodar (Russia). Statistically demonstrable difference (P <0,05) in the content of pigments was also recorded in a group of Indian teas (from lowlands) and, from a group of Chinese teas, a statistical difference (P <0,05) was demonstrated in the content of pigments in the mountain teas. On the basis of the results it can be concluded that the quality of green tea is mainly influenced by the processing method depending on the processing area (the factory), than by their country of origin.