DETERMINATION OF TOTAL POLYPHENOL IN COMMERCIAL TEA BRANDS AVAILABLE IN LOCAL MARKET OF BANGLADESH

Abstract

Tea is the most widely consumed beverage in the world. Tea leaves are a source of polyphenols which have antioxidant capacity. Fourteen marketed brands of black tea, green tea and white tea of Bangladesh (viz. Matcha green tea, Kazi and Kazi green tea,Taaza (Brooke bond), Bengal classic tea, Jafflong tea, Kazi & Kazi black tea, Ispahani premium green tea, Fresh premium tea, Jafflong green tea, Ispahani mirzapur tea , Lipton green tea, Fresh premium green tea, Twinings of Londan Black tea and Silver Needle white tea) were randomly collected from the local supermarkets to observe the amount of polyphenol in tea using UV-spectrophotometer as a tool. The research was carried out during the time from December 2020 to March 2021 at the Agro-environmental chemistry laboratory of Department of Agricultural Chemistry, Sher-e-Bangla Agricultural University, Dhaka. The contents of methanol soluble polyphenol and hot water-soluble polyphenol were determined in fourteen tea brands. Hot water extraction showed the highest polyphenol content. The contents of hot watersoluble

polyphenols ranged from 32.85± 1.6 to 144.50± 18.21mg FAE/g of tea. The contents of methanol soluble or free phenolics was estimated among the fourteen tea brands of tea ranging from 9.86 ± 3.95 to 138.25 ± 15.95 mg/g of tea dry weight basis. Green teas showed the highest amount of polyphenol content. Black tea has lower polyphenol content. In relation with polyphenol green tea seems to be healthier to drink.