Effects of single- and dual-frequency ultrasound on the functionality of egg white protein

The effects of high-power ultrasound (HP-US) treatment with different frequencies, temperatures, and durations on the physicochemical and structural properties of untreated and HP-US-treated egg white protein (EWP) were evaluated. Results indicated that the solubility of EWP was significantly improved after HP-US treatment, especially under the continuous dual frequency of 20/40 kHz. The foaming capacity of the EWP also depended on the treatment frequency, temperature, and duration, and foaming stability increased considerably in the HP-US-treated EWP compared with the untreated one. The particle size of the HP-US-treated EWP greatly decreased compared with that of untreated EWP. Results of low-field nuclear magnetic resonance analysis indicated that more water molecules were trapped in the EWP gel structure as free water after HP-US treatment. Therefore, the green technology of HP-US treatment can improve the physicochemical properties of EWP because of its sonochemical effect on the molecular conformation of EWP.