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.

Effects of gardenia seed, green tea, and cactus pear in rice batter on the chemical quality of lotus root bugak and frying oil

“…The contents of β-carotene and lutein were 847.13±2.51 and 4.86±0.18 mg/kg in gardenia seed, 22,402.77±1,206.95 and 223.48±6.16 mg/kg in green tea, and 663.81 ±24.14 and 14.41±0.93 mg/kg in cactus pear, respectively. These values were higher than the previously reported values in gardenia seed (12.7 mg/kg; 14) and green tea (700 mg/kg; 15); such differences were thought to be due to different genotypes, cultivating conditions, and/or processing conditions (12,13).…”

“…Chlorophylls a and b were detected only in green tea powder at 59.46±0.77 and 151.91±7.26 mg/kg, respectively, which were lower than the reported values (11). A wide range of the chlorophyll contents in green tea depending on the cultivating area and processing method has been previously reported (12,13). Carotenoids detected in the food materials included β-carotene and lutein.…”

Chlorophyll as an indicator of green tea quality

“…They found chlorophyll values averaging 1.4 mg per 1 g of dry substance. Ošťádalová et al (2014) reported the amount of chlorophyll in particular types of teas, coming from the same growing area, but from the 2013 harvest. They found chlorophyll values averaging 1.39 mg per 1 g of dry substance.…”

“…The samples prepared in this way were extracted for 15 minutes and then their absorbance was measured. In all cases, the measurement maximum absorption of the absorption spectrum was checked in a broader wavelength range (Ošťádalová et al 2014). …”

Quantitative visualization of photosynthetic pigments in tea leaves based on Raman spectroscopy and calibration model transfer

“…The world's tea production exceeds 4 million tons per year and more than 2 billion people consume tea [ 1 ]. Tea, which contains high levels of antioxidants and can prevent many diseases including cardiovascular and cancer, has received more and more attention from people [ 2 ]. Photosynthesis is the determinant of productivity and the basis of plant growth and development, and an important source of carbon in plants.…”