Abstract: This study was carried out in order to explore the effect of high intensity ultrasound on the structural and functional characteristics of Litopenaeus vannamei proteins. After being ultrasonicated for 0, 5, 15, 25 or 35 min at 300 W power, 20 kHz frequency and 382 W/cm2 power intensity, the change in the content of tropomyosin was evaluated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and enzyme-linked immunosorbent assay (ELISA). It was found that ultrasonic treatment could effectively reduce the allergenicity of shrimp proteins. Fourier transform infrared (FTIR) spectra showed that the secondary structure of the proteins was transformed from random coil to β-turn and β-fold after ultrasonic treatments, and the content of sulfhydryl groups increased, contributing to the formation of a stable three-dimensional network structure. Moreover, the average particle size significantly decreased, and the total antioxidant capacity, free amino acid content and in vitro digestibility of the proteins significantly increased. In conclusion, high-intensity ultrasonic treatment can not only reduce the allergenicity of shrimp proteins, but also change their structure and functional characteristics, and improve their potential nutritional value. This study provides a reference for non-thermal processing and deep processing of Litopenaeus vannamei.

Key words: Litopenaeus vannamei; ultrasound; tropomyosin; functional characteristics; secondary structure