VARIATION IN TOTAL POLYPHENOL CONTENT, ANTIOXIDANT POTENTIAL, THEAFLAVIN AND THEARUBIGINS CONTENT OF BOPF GRADE SRI LANKAN BLACK TEAS (Camellia sinensis L.) OF DIFFERENT CLIMATIC ELEVATIONS AND BOPF GRADE COMMERCIALLY AVAILABLE BLACK TEAS IN SRI LANKA.

Author (s) : Dr. S. POONGODI, Dr. R. JAYAGANESH & Ms. S. SHENBAGAVALLI

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Abstract :
Tea is the most common nonalcoholic beverage in the world next to the water. Its popularity is attributed to its sensory properties, stimulating effects and potential health benefits. Black tea is the most popular tea among three major types of tea namely green, oolong and black tea. Unblended Sri Lankan black teas are classified as high grown, medium grown and low grown based on their geographical origin. In the quality control purposes, it is an added advantage if suitable chemical data that are helpful to distinguish between different teas are available. However some studies have been reported regarding the chemical parameters of black teas from different agro climatic elevations of Sri Lanka, such details like purity, cultivar and the particle size of teas have not been specified. And also there is no systematic screening has been reported for black tea commercialized in Sri Lankan market. So the main objective of this study was to analyze the total polyphenol content, antioxidant activity & total thearubigins & theaflavins content in unblended Sri Lankan black teas collected from factories representing different tea growing regions. And also to analyze the same biochemical parameters for the black teas that are commercialized in Sri Lankan market. During the month of April 2012, BOPF grade fermented black tea samples produced by TRI 2025 were collected from twelve tea plantations of different agro climatic elevations. All the teas were processed according to the orthodox-rotor vane method. Ten commercialized samples of different brands were also analyzed. Total phenolic content (ISO 14502-1 method), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity, TF (flavognost method) and TR content were determined for each sample. Mid grown tea showed highest mean values in TPP content (15.9454 ± 2.5778 % GAE), TF content (22.2200 ± 3.9575 µmol/g) and TR content (14.6031 ± 1.8970 %). The antioxidant activity was well correlated with the total polyphenol content (P < 0.05) and thearubigins contents (P < 0.05). Lowest mean EC50 value (49.6791 ± 5.9475 µg/ml) was obtained by mid grown tea samples, indicating highest antioxidant activity among others. Rilagala plantation showed the maximum values in TPP content, antioxidant activity, TF and TR contents among others.

Keywords : black tea; antioxidant activity; total polyphenolic content; theaflavin; thearubigin 1st International Conference on

Conference Date : 17/09/2021

Pages : 190

Paper ID : IESMDT188