六堡茶中咖啡因加速溶剂萃取(ASE)的工艺研究

Accelerated Solvent Extraction (ASE) of Caffeine from Liupao Tea

摘要:

本研究探讨了加速溶剂萃取(ASE)法提取六堡茶中咖啡因。采用快速溶剂萃取仪提取六堡茶中咖啡因，以乙醇为萃取溶剂，利用单因素试验考察乙醇浓度对提取率的影响，设置仪器压力为10 MPa，选择萃取温度、萃取时间、循环次数等影响咖啡因得率的因素进行L9(34)正交试验，以咖啡因得率为主要指标，考察ASE法最佳提取条件并与微波辅助提取法进行比较。结果显示ASE法提取六堡茶中咖啡因的最优化条件是以无水乙醇为溶剂，在温度120 ℃条件下静态萃取3次，每次10 min；经ASE法提取，咖啡因的平均得率为20.374 mg/g，其提取物经过C18固相萃取小柱处理不仅能除去六堡茶提取液中的大部分杂质，而且对咖啡因的含量几乎没有影响，经微波辅助法提取，咖啡因的平均得率为17.028 mg/g。说明ASE法提取六堡茶中咖啡因，其提取率高于微波辅助提取法，且能保证提取物的质量。

Abstract:

This study investigated the extraction of caffeine from Liupao tea by accelerated solvent extraction (ASE). The caffeine from Liupao tea was extracted with an accelerated solvent extractor and ethanol as the extraction solvent. The effect of ethanol concentration on the extraction rate by single factor experiments, with the instrument pressure set to 10 MPa. The L9(34) orthogonal test was carried out by selecting the factors affecting the caffeine yield such as extraction temperature, extraction time and cycle number. Taking the caffeine yield as the main index, the optimal extraction conditions for the ASE method were investigated and compared with the microwave-assisted extraction method. The results showed that the optimal extraction conditions for extracting caffeine from Liupao tea by ASE were: anhydrous ethanol as the solvent; static extraction 3 times at 120 ℃ with each lasting for10 min. The average yield of caffeine for the ASE method was 20.374 mg/g, and the treatment with a C18 solid phase extraction column could only remove most of the impurities in the obtained Liupao tea extract with little effect on the content of caffeine. The average yield of caffeine was 17.028 mg/g for the microwave-assisted extraction. These results indicated that the extraction rate of caffeine from Liupao tea by ASE was higher than that by microwave-assisted extraction, and the quality of the obtained extract could be guaranteed.