Optimization of the extraction technology of EGCG from green tea

In order to prepare epigallocatechin-3-gallate(EGCG) from tea by caffeine precipitation and solvent partition,the experiment of technology optimization for EGCG extraction from tea was carried out with the design of the rotation-regression-orthogonal combination.The parameter models with the purity of EGCG as target functions were established.The optimization parameters for the extraction of EGCG from tea in caffeine precipitation and solvent partition system were as follows: water temperature,caffeine concentration,the number of partition with chloroform,with ethyl hexanoate,and with propyl acetate.Additionally,the mathematic model was well established to estimate the purity of EGCG within the investigated range.By the extraction parameters,the EGCG production system was obtained.The product was gained and then measured by high performance liquid chromatography(HPLC).The results indicated that the best EGCG extraction parameters were water temperature,80 ℃;caffeine concentration,30 mmol·L-1;the number of partition with chloroform,5;with ethyl hexanoate,3;and with propyl acetate,3.Under these extraction parameters,the product was obtained,finally its purity was more than 80.3%,as judged by HPLC.