TAILIEUCHUNG - Trích ly có hỗ trợ vi sóng các polyphenol từ búp trà tươi
Chồi trà tươi (một chồi và hai hoặc ba lá non) được chiết xuất sử dụng phương pháp chiết vi sóng hỗ trợ (MAE). Một số yếu tố như ethanol nồng độ ( (khối lượng thể tích)), chất liệu: tỷ lệ dung môi (1: 4 đến 1:12), chiết thời gian, công suất lò được nghiên cứu để tối ưu hóa các điều kiện ở quy mô phòng thí nghiệm. MAE lưu trữ tốt năng suất (82,46%) sau 6 phút bức xạ vi sóng, cao hơn so với chiết xuất tại nhiệt độ phòng trong 24 giờ, khai thác nhiệt thông thường ở nhiệt độ hồi lưu ở 60 phút hoặc siêu âm hỗ trợ khai thác trong 60 phút. | TẠP CHÍ PHÁT TRIỂN KH&CN, TẬP 9, SỐ 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 th st (Manuscript Received on January 26 , 2006, Manuscript Revised August 21 , 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 ( (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 ( %) 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 ( % 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 .
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