微波辅助提取茶叶中咖啡碱的工艺研究

目的]探讨茶叶中咖啡碱的微波提取法。方法]通过单因素试验,利用微波辐射萃取法提取茶叶中的咖啡碱,考虑不同因素对咖啡碱提取率的影响,以确立微波条件下提取咖啡碱的最佳工艺条件。结果]对咖啡碱提取率影响较大的因素有料液比、提取溶剂、提取时间、提取温度、微波时间、微波功率,影响不明显的因素有茶叶的粉碎度和pH值。最佳的提取工艺条件：选用未粉碎的茶叶作为原料,乙醇作为提取溶剂,料液比1∶30,提取时间40 m in,提取温度90℃,pH值为4,微波功率为500 W,微波作用时间为4 m in。该条件下,茶叶中咖啡碱的提取率达到3.94%。结论]微波应用于咖啡碱的提取,具有高效、节能、无污染、降低成本等优点。

Study on the Caffeine Extracted from the Green Tea with the Microwave-assisted Technique

Objective] The method of the caffeine extracted from the green tea with the microwave-assisted technique was experimented.Method] The optimal technical condition of the caffeine extracted from the green tea with the microwave-assisted technique was assured through the single factor experiment in the different factors affecting the efficiency.Result] The result indicated that the ration of raw material to solution,the solvent,the digestion time and temperature,the microwave power greatly affected the extraction rate and the smashing degree of tea and the pH value did not obviously affect the extraction rate.The best extracting condition was as follows: the no-smashing tea was selected as raw material;the ethanol,as solvent;the ration of raw material to solution,1∶ 30;the digestion time,40 min;the digestion temperature,90 ℃;the pH value,4;the microwave power,500 W and the radiation time,4 min,under which condition,the output ratio of caffeine was 3.94%.Conclusion] The technique was high-efficiency,energy-saving,non-population and low cost.