Insight into effects of high intensity ultrasound treatment on foamability and physicochemical properties of frozen egg white protein

Frozen storage can greatly improve the shelf life of fresh egg white protein (EWP), but at the same time, it will also lead to the reduction of protein foaming and can not meet the application needs. Herein, high-intensity ultrasound (HIUS) was used to improve the foam characteristics of EWP in different frozen storage periods. The results showed that compared with fresh egg white, the foaming ability of EWP with different freezing times (0, 3, 7, 14, 21 days) after HIUS treatment (20 kHz, 60% amplitude, 5 min) was significantly improved, especially the EWP after 21 days of frozen storage was doubled by HIUS induction. Furthermore, it was found that the improvement of EWP foamability was mainly due to the enhancement of surface hydrophobicity and the decrease of apparent viscosity, which increased the diffusion rate of protein to the interface and its adsorption amount at the interface. These results showed that HIUS was a simple, efficient and residue free way to improve the foam characteristics of frozen EWP, which has strong promotion and application value.