Production of green tea EGC- and EGCG-enriched fractions by a two-step extraction procedure
Author: Laurent Bazinet and David Labbé and Angelo Tremblay
The aim of the present work was to test the feasibility of a two-step extraction procedure to fractionate EGCG and EGC from green tea. This work was based on previous observations that there was a variable interdependence between the brewing duration and the brewing temperature on catechin concentrations: EGC being a time-dependent compound while EGCG being a time/temperature-dependent compound. It appeared from these results that it was possible to produce from green tea, on a simple way with adding no organic solvent, an EGC-enriched extract (78.9% total catechins) in the first step and an EGCG-enriched extract (47.6% total catechins) in the second step. The two-step brewing procedure based on the temperature-dependent solubilization of both major catechins, EGC and EGCG, allowed the production of such extracts by decreasing ash and EGC contents during the second step extraction.