Abstract: In the light of the current great interest in esterified catechins in tea science and the demand for diverse industrial products of tea polyphenols, macroporous resin LP-8 was chosen to separate tea polyphenols with high proportion of esterified catechins in this study. In static adsorption and desorption experiments, resin LP-8 was proven to have differential selectivity for tea polyphenols (containing esterified catechins) and caffeine. Ideal recovery of tea polyphenols could be subsequently obtained by elution with 70% ethanol. As a result, resin LP-8 is promising to prepare tea polyphenols with high proportion of esterified catechins. Furthermore, static adsorption kinetics and isothermal adsorption experiments were conducted, and the saturated adsorption capacity of resin LP-8 at 25 ℃ was calculated to be 70.9 mg/g by fitting the data obtained to the Langmuir equation. The optimal dynamic adsorption conditions were determined as 1 BV/h of loading flow rate and 30 mg/mL of sample concentration. Different concentrations of ethanol were used in gradient dynamic desorption, and the tea polyphenols in the pooled sample of 40%–60% ethanol eluates contained 78.0% esterified catechins (61.0% epigallocatechin gallate (EGCG)). In conclusion, tea polyphenols with high proportion of esterified catechins were successfully obtained by the application of macroporous resin LP-8.

Key words: tea, tea polyphenols, macroporous resin, esterified catechins, epigallocatechin gallate