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Fresh tea shoots (one shoot and two or three young leaves) were extracted using microwave-assisted extraction method (MAE). Several factors such as ethanol concentrations (0-99.5o (volume percentage)), material: solvent ratio (1:4 to 1:12), extraction time, oven power were studied to optimise conditions at laboratory scale. | TẠP CHÍ PHÁT TRIỂN KH CN TẬP 9 SÓ 8 -2006 MICROWAVE-ASSISTED EXTRACTION OF POLYPHENOLS FROM FRESH TEA SHOOT Pham Thanh Quan 1 Tong Van Hang 2 Nguyen Hai Ha 1 Nguyen Xuan De 1 Truong Ngoc Tuyen 1 1 University of Technology VNU-HCM 2 International University VNU-HCM Manuscript Received on January 26 2006 Manuscript Revised August 21st 2006 ABSTRACT Fresh tea shoots one shoot and two or three young leaves were extracted using microwave-assisted extraction method MAE . Several factors such as ethanol concentrations 0-99.5o volume percentage material solvent ratio 1 4 to 1 12 extraction time oven power were studied to optimise conditions at laboratory scale. MAE archived good yield 82.46 after 6 minutes microwave radiation that was higher than that of extraction at room temperature in 24 hours conventional heating extraction at reflux temperature in 60 minutes or ultrasound-assisted extraction in 60 minutes. Afterward MAE method was employed to investigate five types LD97 LDP1 PH1 TB14 HAT of tea Camellia sinensis L. O. Kuntze from Bao Loc Lam Dong. HAT 20.49 dried weight of total catechins was found as suitable material for polyphenols extraction. Keywords Polyphenols catechins tea extract extraction microwave-assisted extraction. 1. INTRODUCTION Tea has been one of the most consumed beverages in all over the world. Tea is used not only as fresh drink but also as traditional herb which has many benefits for human health. Recently tea has attracted scientific attention for its anticancer and antioxidant activities 10 . Polyphenols in green tea are believed as excellent free radical scavengers. Several clinical studies have proved polyphenols to be active in cancer prevention in several ways. Polyphenols have also been recently recognized as functionally active molecules possessing antioxidant anticancer anti-mutagenic properties as well as exerting protective effects against cardiovascular and other diseases 13 15 . This is primary because of the affect of polyphenols .
