Effect of salts and nonionic surfactants on thermal characteristics of egg white proteins.

Effect of salts (Sodium chloride (NaCl), Sodium sulfate (Na2SO4), Ammonium sulfate ((NH4)2SO4), and nonionic surfactants (glycerol, tween20, tween80) on thermal properties of egg white proteins as a whole were investigated. Egg white solutions with additive (0, 0.5 and 1%) were collected after 0, 1 and 2min heat treatment. Physico-chemical properties of egg white proteins were evaluated by measuring heat coagulation time, solubility and turbidity of solution. Adding glycerol caused the most significant decrease in turbidity and increase in heat coagulation time and solubility of egg white, although Sodium Chloride had the least positive impact on physico-chemical properties of egg white under heat treatment. The Fourier transform infrared (FT-IR) spectroscopy analysis of heat treated egg white proteins as a whole with additives demonstrated changes in secondary protein structure, which are presented regarding the shape, intensity and position of FT-IR band. Meanwhile, it showed a good correlation with the physico-chemical properties consequences. Generally, the effect of nonionic surfactants were more noticeable than that of salts in preventing of egg white proteins aggregation under heat treatment. By improving thermal stability of egg white proteins, its usage in thermal processing industry can be evolved.