茶叶浸提液微波辅助萃取过程中溶剂选择的差异

Differences between different solvents in microwave-assisted extraction of green tea extract

研究了绿茶中活性成分儿茶素单体在不同性质的溶剂(甲醇、乙醇、水、乙酸乙酯)下,微波辅助萃取的效率和选择性差异。实验结果发现,酯型儿茶素单体(L-EGCG和L-ECG)用甲醇或乙醇萃取较用水萃取效率高,其他三种简单儿茶素单体(L-EGC,D,L-C,L-EC)则是以纯水作为萃取溶剂萃取效率为佳。乙酸乙酯对儿茶素各单体的浸出量相对水、甲醇和乙醇都大幅减少。适当增加萃取溶剂的离子浓度,会有利于微波辅助萃取效率的提高,但溶剂的离子浓度过大时,会降低儿茶素各单体的浸出量。

Research was carried out on the differences between different solvents in microwave assisted extraction of green tea extract. The results showed that the extraction yields of the main two catechin monomers,epigallocatectin gallate（L EGCG） and epicatectin gallate（L ECG） were higher in the cases of methanol and ethanol as solvent than purified water. Compared with purified water,methanol and ethanol,ethyl acetate showed the lowest extraction yields of catechins as solvent. Appropriate addition of NaCl in water could improve the efficiency of microwave assisted extraction.