Investigation of Changes in Yolk Moisture

Experiments were conducted to study the movement of water across the vitelline membrane of the hen’s egg during storage. Eggs refrigerated at 6°C. for 7 days had less yolk moisture, lower albumen pH and a higher yolk index than those held at room temperature, 27.5°C. Preventing gas exchange under both refrigerated and room temperature conditions resulted in a decrease in albumen pH and no change in yolk index over a 7-day storage period. When gas exchange was permitted, under these conditions, albumen pH increased and yolk index decreased. Yolk moisture decreased under closed, refrigerated conditions and increased under closed, room temperature conditions. Removing the egg from the shell and separating the yolk from the normal relationship to the albumen produced larger changes than leaving them in the shell. Yolks stored under refrigerated conditions in fresh thick albumen had less moisture than those stored in thin albumen. Aging the albumen at pH 8.9 resulted in yolks stored in thick and thin albumen having the same amount of moisture. No changes in yolk index or albumen pH could be attributed to storing in aged or fresh thick and thin albumen.