Controlled modification of liquid egg white using cylindrical focused ultrasound: Functionality enhancement while maintaining protein integrity.

This study evaluated the effect of cylindrical focused ultrasound to improve the multifunctionality of liquid egg white and investigated the underlying protein structural changes associated with these functional improvements. Liquid egg white was treated at 380 kHz and 100 W for 0, 10, 20, or 30 min at 25 °C. Compared with the untreated control, 20 min of treatment significantly enhanced the foaming and emulsifying properties of egg white (p < 0.05), whereas no significant differences were observed between the 20 and 30 min treatments (p > 0.05). After 20 min of treatment, foaming capacity and foaming stability increased from 34.45 % to 57.78 % and from 71.30 % to 88.66 %, respectively (p < 0.05). Similarly, the emulsifying activity index and emulsifying stability increased from 20.86 to 31.77 m2/g and from 25.68 to 53.68 min, respectively (p < 0.05). These improvements were accompanied by reduced particle size, increased absolute zeta potential, and enhanced surface hydrophobicity, whereas SDS-PAGE profiles, carbonyl content, pH, and total free amino acid content remained unchanged. In addition, 20 min of treatment significantly increased the hardness and chewiness of heat-induced egg white gels (p < 0.05), without changing cooking yield, cooking loss, or whiteness index (p > 0.05). In conclusion, cylindrical focused ultrasound treatment for 20 min improved the foaming, emulsifying, and heat-induced gel texture properties of egg whites while maintaining protein structural integrity, demonstrating its potential as an effective controlled-processing method for egg white-based food applications.