Effect of Combination of Salt and pH on Functional Properties of Frozen-Thawed Egg Yolk

Abstract

Egg yolk undergoes an irreversible gelation process at temperatures below −6 °C, which greatly impairs its application and increases its apparent viscosity. This work was aimed to investigate the effect of salt and pH in preventing the gelation of frozen-thawed egg yolk. Before freezing, 5% of salt was added into the pasteurized liquid egg yolk, then pH was adjusted to different levels (5.7, 6.0 and 6.3) with citric acid. After that, the yolk was stored at −18 °C for four weeks. Rheological and thermal properties of the fresh and frozen-thawed egg yolk were measured. In addition, the colour, turbidity and emulsifying properties were also determined. The results showed that pH of all samples increased during frozen storage, but at different rates. The combination of 5% of salt and pH at 6.0 and 6.3 could prevent the gelation, resulting in rheological properties more like the fresh liquid egg yolk. In addition, emulsifying properties also obtained better results for treated yolk. Moreover, L* value of treated egg yolk was higher before freezing and became lower after storage compared to control. The results of this work found that the combination of 5% of salt and adjusted pH could prevent the gelation of frozen-thawed liquid yolk.

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

“…The pH of all samples increased significantly with the increasing of storage time. This finding was similar to other reports (Hidas et al, 2021b;Huang et al, 1997).…”

Research Note: Aggregation-depolymerization of chicken egg yolk granule under different food processing conditions

“…Freezing-thawing caused gelation of egg yolk, and both plasma and yolk granule were involved in the gelation process, and hydrophobic interactions and disulfide bonds were found in the thawed yolk ( Hidas et al, 2021 ). In the present study, gelation occurred in the freezing-thawing-treated samples even at low concentrations of yolk granule solutions, and was more pronounced in the samples that was freezing-thawing 3-time.…”