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.
