Emulsion, gelation, physicochemical properties and microstructure of phosphorylated and succinylated egg yolk

Abstract This study aimed to verify influence of sodium tripolyphosphate and succinic anhydride on functional characteristics of egg yolk (EY). Addition of the two salts led to modification of yolk protein, and modification degree improved with increasing reaction time. Two modification methods caused a two-to three-fold enhancement in emulsion stability of EY. The hardness of yolk gels was effectively increased by 29.73% or 56.61%. The improved emulsion stability and gelling properties of the modified EY resulted from changed structures of EY protein. Physicochemical properties, such as increased solubility as well as decreased surface hydrophobicity, particle size of yolk granules, and zeta potential, contributed to the enhanced functional properties. The result of scanning electron microscopy revealed that modification was beneficial in forming fine and compact EY gel network. The gel strength and water-holding capability of the yolk gels were thus considerably increased.