Simultaneous purification of tea polyphenols and caffeine from discarded green tea by macroporous adsorption resins.

摘要

To separate and purify tea polyphenols and caffeine from discarded green tea crude extract with macroporous adsorption resins (MARs), the adsorption properties of twenty kinds of MARs are systematically evaluated. The results show that GS-18 has higher separation efficiency than other MARs, and the experimental data fit best to the pseudo-second-order kinetic model. And adsorption isotherms and thermodynamics of tea polyphenols and caffeine on GS-18 are investigated. The separation parameters of tea polyphenols and caffeine from discarded green tea crude extract are optimized according to dynamic adsorption/desorption experiments with the column packed with GS-18. Through only one cycle treatment, the content of tea polyphenols increases 3.0-fold from 20 to 60% with a recovery yield of 91% and that of caffeine increases 3.1-fold from 7 to 22% with a recovery yield of 98%. The results demonstrate that the method of MARs will provide useful help for the development of large-scale separation of tea polyphenols and caffeine from discarded green tea in industry.