Chitosan based supermacroporous continuous separation medium was prepared by variable temperature freezing method and used for the adsorption and separation of tea polyphenols from tea. The cross-linking reaction,pore forming and molding of chitosan gel were completed in one step. The porosity of the medium was 85% ~ 90% and the pore range was 500 ~ 1000μm. Based on the adsorption capacity and desorption ratio of tea polyphenols,the adsorption and desorption parameters of the supermacroporous continuous medium for tea polyphenols were obtained as follows :the flow rate of the adsorption solution was 0.70 mL/min,the adsorption temperature was 25℃,the pH was 4.5 ~ 5.0;the desorption solution was 80% ethanol aqueous solution,the flow rate was 0.90 mL/min,the dosage was 5 BV,and the temperature was 40℃. The maximum adsorption capacity of the supermacroporous continuous medium was 256.4 mg/g,the desorption ratio of tea polyphenols was 76%,the average extraction rate of tea polyphenols was 12.3%,and the purity was 96.5%. The preparation method abandons freeze drying method to obtain chitosan-based porous adsorption medium. The porosity of the separation medium is uniform. It can replace the traditional bulk adsorbent resin for the adsorption and separation of tea polyphenols.
China Food Additives