Abstract: In this study, we examined the effects of combined addition of low ester pectin (LEP) and NaCl on improving the gel properties of liquid whole egg. NaCl was added at 0.10% and 0.15% (m/m) and LEP at 0.10%, 0.20%, and 0.30% (m/m). Changes in the gel properties and microstructure of liquid whole egg were investigated, and the underlying mechanism was analyzed on the basis of the changes in physicochemical properties. The results showed that the combined addition of NaCl at 0.10% and LEP had the best synergistic effect on improving gel properties of liquid whole egg. The addition of NaCl and LEP increased negative charges in the system, promoted the formation of soluble protein aggregates, and significantly increased the absolute value of zeta potential, average particle size D4,3 and soluble protein content (P < 0.05). During the gel formation process, the complexation of LEP with egg proteins could enhance the density of the three-dimensional network structure and complexation regions were formed, both of which were helpful to retain free water. The results of rheological and gel properties showed that the elastic modulus (G’), gel strength, water-holding capacity and immobilized water content rose with the increase of LEP content. The best gel properties of liquid whole egg were observed with the addition of 0.10% NaCl and 0.20% LEP, which showed a 2.01-fold increase in hardness, an increase of 30.64% and 16.48% in elasticity and water-holding capacity, respectively, and a 2.50-fold increase in the content of immobilized water, and a lot of tiny pores were found on the gel surface. Therefore, the combined addition of NaCl and LEP can improve gel texture of liquid whole egg, which provides the theoretical basis for expanding the application of liquid whole egg in the food processing field.

Key words: liquid whole egg, NaCl, low ester pectin, gel properties