Improved gelling and emulsifying properties of myofibrillar protein from frozen shrimp (Litopenaeus vannamei) by high-intensity ultrasound

shrimp protein functionality during chilling storage recently attention due to its adverse effects on shrimp quality. The high-intensity ultrasound (20 kHz, 400 W) was applied to improve the protein structure and functional properties of frozen shrimp (Litopenaeus vannamei) in this study. Fourier transform infrared (FTIR) spectroscopy showed that the cavitation effect of ultrasound could change the secondary structure of myofibrillar protein (MP) by turning the alpha-helix and random coil to beta-sheet and beta-turn. The unfolding of MP conformation increased the reactive sulfhydryl content and surface hydrophobicity accordingly. The structure changes eventually led to the significant improvement of protein functionality. Gel properties analysis showed after ultrasonic treatment, the gel strength and water holding capacity of protein gels were increased gradually. Scanning electron microscopy (SEM) images also demonstrated that ultrasound treatment contributed to the formation of stable network structures in protein gels. In addition, ultrasonic ho-mogenization could increase the emulsifying ability (45.54 m2/g to 78.82 m2/g) and stability of protein in a short time, which might be related to the decrease of particle size. Confocal laser scanning microscope (CLSM) analysis further illustrated that ultrasound treatment made the emulsion distribution more uniform. The appli-cation of these findings will improve the deep processing ability and expand the commercialization of frozen shrimp products.

Automated summary

This study utilized high-intensity ultrasound treatment to improve the protein structure and functionality of frozen shrimp. The results showed that ultrasound treatment could change the protein's secondary structure, leading to improved functionality. It also enhanced the gel properties and emulsifying ability of the protein.