HEAT DENATURATION OF OVOMUCIN-LYSOZYME ELECTROSTATIC COMPLEX - A SOURCE OF DAMAGE TO WHIPPING PROPERTIES OF PASTEURIZED EGG WHITE

SUMMARY– A longer whip time is usually required to obtain a meringue of the same specific gravity from pasteurized egg white as from unpasteurized egg white. We have determined the rate at which this change in whipping properties occurs as a function of heating time and pH. The rate of damage is minimal at neutral pH. The activation energy for whipping property damage at pH 7.5 is 140 kcal. Experiments in which either ovomucin or lysozyme concentration of egg white was increased and decreased showed that the reaction producing damage to the whipping properties is first order with respect to both ovomucin and lysozyme concentration. Since an increase of 0.33 in the ionic strength of egg white produces a ten‐fold decrease in the rate of whipping property damage, the reactants are probably present as the ovomucin‐lysozyme electrostatic complex. The product appears to be an irreversibly denatured ovomucin‐lysozyme aggregate or network. Removal of the product restores the whipping properties of the egg white. The whipping property damage is a decrease in the mechanical stability of the foam. For this reason a longer time is needed to whip pasteurized egg white to a satisfactory meringue. Whipping aids such as triethyl citrate or triethyl phosphate compensate for the damage to the whipping properties, but do not appear to reverse the reaction producing damage to the whipping properties of the egg white. Copyright © 1968, Wiley Blackwell. All rights reserved