Effect of different salt concentration on the physical properties of frozen thawed egg yolk

Freezing can enhance the storage time of liquid egg products, but egg yolk undergoes an irreversible textural and structural change when it is cooled to – 6 8 C. In this study, the effects of different salt concentrations on the physical properties of frozen-thawed egg yolk were investigated. The pasteurised liquid egg yolk (LEY) was treated with 4, 5, and 6% of NaCl before freezing and it was stored at – 18 8 C for 4 weeks. The colour, pH, and rheological characteristics (firmness, consistency, cohesiveness, and index of viscosity) of yolk samples were evaluated before and after freezing. Salt treatment resulted in preventing gelation, with decreasing firmness, consistency and viscosity compared to control samples. The pH of all yolk samples increased during frozen storage. The lightness value decreased in treated samples and increased in the control sample after freezing. The results indicated that the applied salt concentrations could inhibit protein aggregation of LEY induced by freezing during the storage period. At least 5% salt concentration could reduce effectively the changes in rheological properties.