ENZYMATIC OXIDATIVE REACTION OF CATECHIN AND CHLOROGENIC ACID IN A MODEL SYSTEM

Enzymatic oxidation of catechin and chlorogenic acid and their mixture was studied at 20 °C and at pH 3.5 and 6.5. The reaction products were monitored by HPLC with diode array detection. The rate of reaction at pH 6.5 was higher than at pH 3.5. The reaction products of catechin oxidation were dimers and other polymers of catechin with low polarity; chlorogenic acid produced mainly polymers. However, the enzymatic oxidation products of the catechin-chlorogenic acid mixture were mainly copolymers which had higher polarity than catechin or chlorogenic acid and were less brown in color than the oxidation products of catechin or chlorogenic acid alone. © 1990, American Chemical Society. All rights reserved.