Study on extraction of tea polyphenol by resin

DM-16X, a macroreticular adsorption resin, was selected as the best adsorbent among 12 types of resins that were used in the adsorption and desorption experiments of tea polyphenol from tea soup. Its process of dynamic adsorption and desorption of tea polyphenol was investigated in detail. It was concluded that its adsorption of tea polyphenol reached best at the adsorption velocity of 6BV/h (1BV=10 mL resin). However, the volume of tea soup with the concentration of tea polyphenol of 1.51 mg/mL was controlled below 12.5BV in case of penetration phenomenon. Its desorption reached best when the volume and velocity of the desorption solution, with the concentration of ethanol of 70%, were 80 mL and 8 BV/h, respectively. Under the optimum operation process, the purity of tea polyphenol obtained could reach as high as 76.57%, in which the total content of four catechins, namely EGC, EC, ECG, EGCG, reached about 65.62% and the concentration of caffeine was about 16.96%.