A Review of the Factors Affecting Emulsifying Characteristics of Hens' Egg Yolk

SUMMARYThis paper reviews factors known to influence the emulsifying characteristics of hens' egg yolk. Processing variables such as homogenization, pasteurization, freezing and dehydration are important considerations in maintaining acceptable emulsifying properties. Spray drying particularly changes the emulsifying ability of yolk.Several yolk components contribute to making yolk an excellent emulsifier but none of them, alone or in combination, are as effective as fresh native yolk. Additives can change the emulsifying capacity of native yolk. Lecithin reduces the capacity whereas sodium stearyol-2-lactylate has been shown to improve it.Other variables such as nutrition, genetic background, and age of the layer also play a role in determining emulsifying characteristics of yolk. There is a considerable need for further research to help clarify the role of processing procedures (freezing, dehydration) individually and collectively on emulsifying properties of yolk.A better understanding of the fundamentals of egg yolk emulsions is needed in order to improve commercial production of egg yolk emulsified food products.