Impact of microwave assisted phosphorylation on the physicochemistry and rehydration behaviour of egg white powder

Three egg white protein powders under different treatments (untreated, microwave-alone treated and microwave-assisted phosphorylation modification) were prepared and their physicochemistry and rehydration behavior were investigated in this study. Scanning electron microscopy (SEM) and physical property measurements showed that the particle size and specific surface area decreased and increased, respectively, in phosphorylated egg white protein and that the particles became looser and more porous. Fourier Transform infrared spectroscopy (FTIR) showed that phosphate groups were successfully introduced into the egg white protein side chain. After phosphorylation modification via microwave treatment of the egg white protein, the egg white protein had increased electronegativity and reduced surface hydrophobicity. Treatment with microwave heating had a negative impact on the rehydration of egg white powder, and phosphorylation modification inhibited this effect to some extent. Compared with microwave-alone treated egg white protein powder, phosphorylated egg white powder showed increased wettability, dispersibility and solubility under alkaline conditions and at 20–40 °C. The maximum solubility of phosphorylated egg white powder (95.52 g/100 g) was higher than that of native egg white powder (93.16 g/100 g) and microwave-alone treated egg white powder (92.76 g/100 g) at pH 10.0.