Study On The Extraction And Purification Of Catechins And The Separation And Preparation Of Epigallocatechin Gallate By Resins

The catechins are the important ingredients in the tea, which have been used in food, medicine, commodities and so on. The epigalllocatechin gallate is one monomer of catechins, which is the best, so more attachment to it. In this paper, the extraction and purification of catechins and the separation and preparation of epigallocatechin gallate by resins was principally studied.1. Response surface methodology was used in studying the extraction of catechins by ethanol, the optimal process conditions: temperature was 90℃, time was 10min, ethanol-tea ratio was 20: l(mL:g), concentration of ethanol was 75% were obtained, and under this condition, the extraction efficiency was 24.79%. The model equation of the extraction efficiency was also gained. The model equation was mostly remarkable and impactful.2. The purification of catechins by resins was studied. X-5 resin was the best of the eight resins which have different quality, the extract was employed as material and orthogonal experiment method was used to optimize the conditions. The results as follows: flow rate 12mL/min, column height 35cm, concentration of extract 10mg/mL.The percentage of catechins increased to 70.01%, the recovery yield of catechins was 90.18%.3. Adsorption and desorption performances of seven kinds of resins adsorbent to EGCG and ECG were studied, the results showed that AB-8 resin was the best one to separate EGCG and ECG , the optimal process conditions: the concentration of crude catechins 10mg/mL, the flow rate 10mL/min and the height of column 35cm. The product with 80%EGCG, 3%ECG was obtained, the recovery rate of EGCG was 49.60%.4. The preparation of epigallocatechin gallate by Sephadex LH-20 was studied. The optimal process conditions were gained, the results as fellows: the diameter of column 2.5cm, the quantity of 80%EGCG catechins 5g, the flow rate 1.0 mL/min and the concentration of ethanol 40%. Under this condition, the chromatogram purity of obtained EGCG monomer was above 98%, the recovery rate of EGCG was 66.59%.5. The purity and chemical structure of EGCG were authenticated by HPLC, MSand IR. The results show that the product was EGCG, and the purity of product wasabove 98%.