The Study On The Extraction Process Of Tea Polyphenols And Caffeine By 2-stage Resin Method

This paper was focusing on separating and purifying Tea Polyphenols and caffeine, finally worked out a new producing technology of Tea Polyphenols and Caffeine by using the techniques of ultrafiltration and 2-stage resin.Through comparing several iron exchange resin and macro-porous resin, ultimately H-600 was applied as the first stage adsorption resin for adsorb the extraction liquid;NKA-II was used as the second stage adsorption resin for recycling caffeine.The extraction liquor was refined by ANDEUF-01 ultrafiltration pilot unit. The experiment results indicated that the 30,000D ultrafiltration membrane could separate protein and Tea Amylose effectively which can cause the contamination to resin. The ultrafiltration can increase the purity of product. On the other hand, it is easy to produce amylose via condensed liquor.The first step adopted solution A as the desorbing liquor for eluting caffeine and the second step chose 85% ethanol as the desorbing liquor for eluting TP. The process can highly separate TP and Caffeine and solved the conventional problem for eluting caffeine by using the toxic solution. The final product contains no toxic reagent, which is safe, no pollution, and according with the theme of "Green Technique".Through setting up mass transfer model of adoption-separation of H-600, we calculated the mass transfer zone height and mass transfer coefficient and established an optimal condition for producing TP and set up a foundation for process scale-up.In this research, we utilized the second adsorption resin for adsorb Caffeine from the first stage desorption liquor. The process successfully separated the caffeine and elution reagent A which did not only reclaimed the caffeine, save the raw material, but decrease the problem of environment pollution.Through this process, the product contains more than 98% of TP, less than 0.5% ofcaffeine, the overall yield reached to 12%;the purity of reclaimed Caffeine was46.5%, and the content of caffeine can achieve to 97.5% after second-sublimationfrom the rough caffeine. Furthermore, the process can flexibly adapt to different requirement of product content by regulating some specific parameters.