银杏叶中单宁提取工艺的优化研究

目的]优化银杏叶中单宁的提取工艺。方法]分别用纯水、无水乙醇1、∶1的乙醇-乙醚、乙醇(95%)-水、丙酮-水以及1∶1∶1的丙酮-无水乙醇-水提取银杏叶中的单宁。结果]以丙酮-水为提取试剂的单宁提取率较高;最佳的溶剂比为1∶2,单宁提取率受溶剂比影响较大,丙酮和水的比例根据原料含水率不同而有变化。随着提取液用量的增加,提取率升高,且固液比为1∶12时提取率最高,但其和固液比1∶10的提取率相差较小,故用1∶10的固液比进行提取比较经济。加入阴离子表面活性剂SDS、DBS,单宁的提取率有所下降,加入两性表面活性剂OP,单宁的提取率下降最多。结论]银杏叶中单宁的最佳提取条件为:以1∶2的丙酮和水为提取剂,回流12 h,固液比为1∶10。

Research on Optimizing the Extraction Technology of Tannins in Ginkgo Leaves

Objective] The aim of the research was to optimize the extraction technology of tannins in ginkgo leaves.Method] The tannins was extracted with pure water,absolute alcohol,alcohol-ether with ratio at 1∶1,alcohol(95%)-water,acetone-water and acetone-absolute alcohol-water with ratio at 1∶1∶1 resp.from ginkgo leaves.Result] The extraction rate of tannins with acetone-water as extraction agent was higher and its optimum solvent ratio was 1∶2.The influence of solvent ratio on the extraction rate of tannins was greater and the ratio of acetone to water varied with water content of raw materials.As the dosage of extraction solution was increased,the extraction rate was increased.The extraction rate was highest when the solid-liquid ratio was 1∶12,but it had less difference from that with solid-liquid ratio at 1∶10.So,it was more economic to extract with solid-liquid ratio at 1∶10.After anionic surfactant SDS and DBS were added,the extraction rate of tannins was decreased a little.When the amphoteric surfactant OP was added,the extraction rate of tannins was decreased most.Conclusion] The extraction condition for tannins in ginkgo leaves was extraction with acetone-water with ratio at 1∶2 as extraction solvent and solid-liquid ratio at 1∶10 by refluxing for 12 h.