从武夷岩茶生产副产品中提取咖啡碱及方法的改进

对茶叶中提取咖啡碱的方法进行了改进，方法为：95％乙醇回流提取一水浴蒸馏回收乙醇→加M如中和鞣酸、吸收乙醇和水分→90℃左右烘干乙醇、水分→油浴180～190℃加热粗提物，咖啡碱升华→纯品．武夷岩茶生产副产品茶末、茶片、茶梗中咖啡因含量分别为：45．65±0．66（mg／g）、42．14±5．68（mg／g）、25．55±0．55（mg／g），从中提取咖啡碱率分别达到0．97±0．30（％）、0．44±0．08（％）、0．38±0．07（％）．用紫外和红外光谱法定性定量，产品为咖啡碱，纯度达到80％以上．对提取条件以正交实验优选结果，主要影响因素为提取温度，最优提取条件为温度70℃、料液比1：12．5、提取时间20min．

An improved method for extracting caffeine from by-product of tea

The method of extracting caffeine from tea had been improved as follows： caffeine was extracted by 95% ethanol circularly → ethanol was recovered by heating in water bath → putting MgO to neutralize tannic acid and to absorb ethanol and water → drying ethanol and water at more or less 90℃→, heating stuff by bathing in 180 - 190℃ oil, caffeine was sublimated → pure. The content of caffeine was 45.65 ± 0.66 （mg/g） in low class tea, 42.14 ±5.68 （mg/g） in crushed tea and 25.55 ± 0.55 （mg/g） in tea stalk. The rate of extracting caffeine was 0.97 ±0.30 （ % ） in low class tea, 0.44 ±0.08 （ % ） in crushed tea, 0.38 ±0.07 （ % ） in tea stalk, respectively. The product was identified by the infrared spectrum and the ultraviolet spectrum analysis, results showed that it was caffeine and its purity was higher than 80%. The extracting conditions were selected by orthogonal test method, the key affecting factor was temperature. The best extracting conditions were that the temperature was 70℃, the rate of material and water was 1 ： 12.5, and the extracting time was 20 min.