龙井绿茶茶多酚提取工艺研究

Study on the extraction of tea polyphenols from lung-ching green tea

为了提高茶多酚的得率和纯度,以龙井绿茶为原料,对茶多酚进行乙醇溶液提取、超声波和微波辅助提取。醇提的最佳条件为乙醇浓度50%,浸提4次,每次45 min,温度为70℃,液固比为20∶1,最大浸提率为24.45%。微波辅助提取最佳条件为预浸30 min,乙醇浓度40%,微波解冻档浸提4 min,浸提2次,液固比为40∶1,最大浸提率为24.70%。超声波辅助浸提最佳条件为乙醇浓度80%,浸提温度50℃,浸提时间25 min,浸提2次,液固比为14∶1,最大浸提率为24.72%。结果表明:微波与超声波提取率稍高于醇提,但三者差别不大。

In order to enhance the yield rate and purity of tea polyphenols,lung - ching green tea was extracted with ethanol solution, ultrasonic assisted extraction and microwave assisted extraction. The optimal extraction conditions with ethanol were set as the following： ethanol concentration 50% ,4 times of 45 -min -extraction at the temperature of 70℃ ,the liquid - solid ratio 20：1 ,and the top extraction rate 24.45%. The optimal conditions for microwave assisted extraction were determined as the following： pre -extracting period 30 min, ethanol concentration 40%, twice microwave thawing extractions for 4min, liquid - solid ratio 40：1 ,and the top extraction rate 24.70%. The optimal extraction conditions for ultrasonic assisted extraction were set as the following： ethanol concentration 80%, extraction temperature 50℃ ,twice extractions for 25 min,liquid - solid ratio 14： 1, and the top extraction rate 24.72%. The final results proved no big difference between these three extraction methods, with better extraction ration of microwave and ultrasonic extraction than that of ethanol.