Impact of NaCl perturbation on physicochemical and structural properties of preheat–treated egg white protein modulating foaming property

This study aimed to investigate the mechanism of NaCl perturbed preheat–treated egg white proteins' (EWPs) physicochemical and structural properties to modulate the foaming property (FP). The results revealed that NaCl regulated the salinolysis (5 mM) – salt precipitation (50 mM) – gradual or complete coverage with hydrated Na+ of the hydration layer (100–300 mM) – enhanced Cl− hydration repulsion (500 mM) of EWP, showing a gradual decrease in aggregates particle size, and reversibility of structural freedom, including moleculer flexibility and surface hydrophobicity. Whereas preheating temperature affected the secondary structure rearrangement and tertiary conformation exposure, and excessive temperature reduced foaming capacity while enhanced foam stability, with a tight correlation between NaCl–mediated EWPs’ FP and the extent of Na+ covering the hydration layer. The findings provide a theoretical basis for processing factors to modulate the protein hydration layer to influence the functional properties. [Display omitted] •NaCl enhanced solubility of aggregates along with reversible surface structure.•FTIR reflected the changes of protein water molecule layer.•Preheating at 66 °C greatly improving foam stability.•500 mM Na+ completely occupied the hydration layer of EWPs.•5 mM NaCl promoted the foaming capacity of 60 °C preheated treated EWPs.