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.
Description:
A Thesis
Submitted to the Faculty of Agriculture
Sher-e-Bangla Agricultural University, Dhaka,
In partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
AGRICULTURAL CHEMISTRY
