Abstract: In order to study the effect of ultrasonic-assisted gallic acid treatment on the gel properties of surimi, the effects of different concentrations of gallic acid (0, 1, 2, 4 and 6 mg/g) combined with ultrasonication on the gel properties of Lateolabrax japonicas myofibrillar protein were investigated by measuring the gel strength, texture characteristics, water distribution status, color, water-holding capacity and cooking loss rate, chemical forces and microstructure. The results showed that with increasing gallic acid content, the gel strength, hardness, chewiness and water-holding capacity of myofibrillar protein showed a trend of first increasing and then decreasing, and the best gel performance was obtained by the addition of 2 mg/g of gallic acid. In addition, it resulted in the highest percentage of peak area for immobilized water, lowest percentage of peak area for free water, highest water-holding capacity and lowest cooking loss, as well as denser microstructure. After ultrasonic treatment, the cooking loss of the gel decreased significantly, and the disulfide content increased significantly. Atom force microscopy (AFM) showed that the myofibrillar protein was orderly aggregated, forming clustered aggregates, and the microstructure of the gel was more homogeneous. Therefore, ultrasound-assisted gallic acid treatment can effectively improve the gel properties of myofibrillar protein from Lateolabrax japonicas.

Key words: ultrasound; Lateolabrax japonicas; gallic acid; myofibrillar protein; gel properties