The effects of high-intensity ultrasound (20 kHz) at varying power pre-treatments (90, 120, 240, 360 and 480 W for 10 min) on foaming and structural properties of egg white were studied in this paper. The highest foaming ability (260.00%) was obtained after 360 W ultrasound treatment which was 4.9-fold to the control group. The lower viscosity and surface tension, and higher protein solubility indicated that the protein was easier to attach to the gas-liquid interface and generate molecular rearrangement. Moreover, the increased free sulfhydryl groups and surface hydrophobicity revealed that the protein adopted a loose structure after ultrasonic processing. SDS-PAGE data proved that subunit of poorly water-soluble ovomucin was declined. Scanning electron microscopy showed different microstructure with smaller aggregates and pore structure compared to non-treated egg white. These results presented more evidence of protein properties under ultrasonic environment, and broadened the application range of ultrasonic technique in food industry.
Keywords: Avian egg; Foaming properties; Protein structure; Ultrasonic cavitation.
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