Effect of pH adjustment during production of egg white powder on foaming and gelling properties

Egg white powders (EWPs) were produced after pH adjustment (pH 6-9) of fresh egg white, followed by spraydrying, and foaming and gelling properties of EWPs were examined. EWP produced after PH adjustment to 6.5 (EWP-6.5) resulted in significantly higher foaming ability and gel hardness than control and other pH-adjusted EWP. Significant increases in surface -SH content and surface hydrophobicity of EWP-6.5 coincided with improved foaming ability and gel hardness. Significantly higher consistency index for reconstituted EWP-6.5 indicates unfolding of egg white protein was substantially increased in EWP-6.5. Decreased a-helix content in EWP-6.5 was confirmed by circular dichroism spectral analysis. These results indicate PH adjustment prior to spray-drying leads to structural changes in egg white proteins, significantly affecting major functionalities of EWP.