ENZYMATIC OXIDATION OF PHLORETIN GLUCOSIDE IN MODEL SYSTEM

Enzymatic oxidation of phloretin glucoside and its effect on chlorogenic acid and catechin in relation to the browning reactions were studied in model systems. Phloretin glucoside alone oxidized slowly and formed the light yellowish reaction products. However, the addition of chlorogenic acid and catechin to phloretin accelerated the reaction of phloretin oxidation by decreasing the lag period of the enzymatic browning reaction significantly. The degree of browning (absorbance at 420 nm) in the mixture was approximately 2 times higher than that of phloretin alone. This synergistic effect of phloretin glucoside with chlorogenic acid or catechin must be taken into account in the browning reactions of apple products.