Electromigration feasibility of green tea catechins

Epigallocatechin gallate (EGCG) is regarded as the most important of the tea catechins. Therefore, methods for producing tea extracts with high EGCG content have been developed. However, these methods have the disadvantages to use solvent or to allow the purification of small volumes. The aim of this exploratory study was to evaluate the feasibility of selectively extracting catechins and caffeine from a green tea solution using an electrodialysis cell. Commercially available membranes (AMX-SB, AFN, PC-400 D and UF-1000 Da) were tested for their potential to allow migration of green tea catechins. This study demonstrated that epigallocatechin (EGC) and EGCG from a green tea infusion can migrate at a high rate through an electrodialysis (ED) system. Among tested membranes, the UF-1000 Da membrane can achieve an EGC and EGCG migration as high as 50%. The other studied catechins and caffeine had no significant migration rate through either the anionics or the UF membranes. Thus, this method combined to a previously developed EGCG preconcentration procedure might allow the production of a green tea extract with highly active biological compound. (c) 2005 Elsevier B.V. All rights reserved.