二氯甲烷萃取绿茶咖啡碱工艺参数的优化

Optimized extraction of tea caffeine from green tea leaves using dichloromethane

为探寻从绿茶中提取咖啡碱的工艺,以二氯甲烷为萃取剂,以咖啡碱得率与纯度为考察指标,采用单因素试验得出较佳茶汤质量分数、料液比(茶汤与二氯甲烷的体积比)、摇匀时间、静置萃取时间、萃取温度、萃取次数和茶汤pH值,选取料液比、摇匀时间、静置萃取时间、萃取温度等4个主要影响因素设计正交试验,并对正交试验结果进行验证。结果表明,以咖啡碱得率为主要考虑因素时,最优工艺参数为茶汤质量分数10%、萃取温度45℃、摇匀时间40 min、静置萃取时间80 min、料液比1∶2.5、萃取2次,此条件下的咖啡碱得率、纯度分别为92.93%、39.58%;以咖啡碱纯度为主要考虑因素时,最优工艺参数为茶汤质量分数10%、萃取温度45℃、摇匀时间35 min、静置萃取时间100 min、料液比为1∶2.5、萃取2次,此条件下咖啡碱的纯度和得率分别为43.37%和85.13%。

In order to optimize the best technical parameters in extracting tea caffeine by dichloromethane, the concentration of tea infusion, ratio of tea infusion and CH2Cl2, extracting standing time, shaking time, extracting temperature, pH value of tea infusion and extracting times were screened, then the main factors including ratio of tea infusion and CH2Cl2, shaking time, extracting standing time and extracting temperature were selected for orthogonal test, the results of which were checked again. The results showed that when mainly considering the yield rate of caffeine, the best parameters were as follows： tea infusion concentration of 10%, extracting temperature of 45℃, shaking time of 40 min, standing time of 80 min, ratio of tea infusion and CH2C12 of 1 ： 2.5, 2 times for extraction. Under this parameter condition, the yield rate of caffeine is 92.93%, the purity of caffeine is 39.58%; when mainly considering the purity of caffeine, the best parameters were as follows： tea infusion concentration of 10%, extracting temperature of 45 ℃, shaking time of 35 min, standing time of 100 rain, ratio of tea infusion and CH2Cl2 of 1 ： 2.5, 2 times for extraction. Under this parameter condition, purity of caffeine is 43.37%, and the yield rate of caffeine is 85.13%.