Abstract: The technology of isolation and purification of theanine extracted from the spent tea water after the tea polyphenols had been removed was studied.Adsorption and separation of theanine by ion exchange after being pretreated by ultrafiltration and decolorization.001×7 resin was adopted as the adsorption medium of ion exchange chromatography to separate theanine from the pretreated liquid.The factors affected the exchange capacity of theanine were assayed,and the kinetics of adsorption also studied.By response surface analysis(RSA)the optimal conditions of adsorption in the fixed-bed of 001×7 resin are resulted as follows:pH of pretreatment liquid 3.4,concentration of theanine 3.0 mg/ml,and sample flow rate 1.7 BV/h.The crude theanine with 58% purity is obtained through desorption with ammonia water at pH 11.3 with the recovery rate of theanine as 82%.

Key words: theanine, ion exchange, adsorption, separation, response surface analysis