Effect of Albumen pH on Yolk Mottling

Abstract

Experiments were conducted to evaluate the effect of albumen pH on the incidence and degree of yolk mottling. Eggs stored for 5 days at 24° C. in a high CO2 or HCl environment, oiled on the top half or completely oiled had lower albumen pH and less yolk mottling than untreated control eggs. Eggs with higher albumen pH had the greatest degree of yolk mottling and lowest vitelline membrane weight. Washed eggs had higher albumen pH and more yolk mottling after 5 days of storage at 24° C. than unwashed eggs. Albumen pH and yolk mottling increased during storage. Oiling the eggs reduced the increase in albumen pH and yolk mottling during storage. Vitelline membrane weight decreased during storage, but was retarded in oiled eggs. Membranes retained in buffers of pH 7.6, 8.0, 8.4, 8.8, or 9.2 for 15 or 24 hours decreased in weight as the pH increased and a significant decrease was obtained at the two higher pH’s. These experiments support the idea that increasing albumen pH causes increased yolk mottling, probably by altering the vitelline membrane.