Abstract: In order to explore the effect of ultrasound on the structure and gel properties of egg white proteins, the spatial structure, molecular distribution and rheological properties of egg white proteins before and after ultrasonic treatment were analyzed, and the water retention and texture properties of egg white gel were determined. Results showed that at ultrasound powers of 200 and 400 W, the structure of some egg white proteins were folded and aggregated; meanwhile, only a small fraction were degraded. On the other hand, at 600 W ultrasound power, egg white proteins were partially degraded, and only a small fraction were aggregated. Therefore, ultrasound could increased the particle sizes of some proteins, and decreased the particle sizes of others, narrowing the overall particle size distribution. Egg white treated at 200 W for 10 min or at 600 W for 30 min had similar rheological properties to those of a liquid. At all three powers, water-holding capacity of egg white gel was increased. Ultrasonic treatment at 200 or 400 W enhanced gel strength, making the gel more firm and compacted. On the contrary, ultrasonic treatment at 600 W for 30 min significantly decreased gel strength and consequently decreased gel stability. These results may provide a basis for improving gel properties of egg white proteins.

Key words: ultrasonic, egg white protein, spatial structure, gel properties, modification