Whole egg whipping properties as affected by albumen and yolk fraction changes

Both albumen and yolk proteins contribute to functional properties of whole egg: albumen mainly performs as a foaming agent and yolk as an emulsifier. This study concerns the variation in the albumen to yolk ratio of whole egg, and its influence on whole egg whipping properties. The natural modification in albumen to yolk ratio of eggs from aging hens proved to be a relevant source of variation. As the hens grew older, egg composition changed showing a decrease in total protein content and albumen protein, and an increase in the percentage of yolk (as well as fat percentage), as a consequence of a reduction in the albumen to yolk ratio. These composition modifications affected whole egg foam consistency and stability, while no relationships were found with overrun. In particular, the percentage increase in yolk fraction during hen aging impaired overall whipping performances of whole egg. The implications for whole egg applications in food products are discussed.