Abstract: To study the feasibility of electron beam irradiation for application to aquatic products, the effects of different electron beam irradiation doses (1, 3, 5 and 7 kGy) on the biochemical properties and structure of myofibrillar protein from Lateolabrax japonicus meat such as salt-soluble protein content, sulfhydryl content, disulfide bond content, Ca2+-ATPase activity, surface hydrophobicity, carbonyl content and conformation. The results showed that total sulfhydryl content was significantly higher in the 1 kGy group compared to the control group (P < 0.05), while there was no significant change in any other indices (P > 0.05). As the irradiation dose continued to increase, the contents of salt-soluble protein content and reactive sulfhydryl and ATPase activity decreased significantly whereas carbonyl and disulfide bond contents increased; higher irradiation dose resulted in more significant changes. The surface hydrophobicity of myofibrillar protein rose with irradiation dose up to 5 kGy and then decreased at higher doses. Circular dichroism (CD) spectroscopic analysis indicated that the conformation of myofibrillar protein was converted from an α-helix to β-sheet structure as a result of increasing irradiation dose. Higher doses of electron beam irradiation could cause the oxidation of myofibrillar protein. To minimize the effect on myofibrillar protein, L. japonicus meat should be irradiated at low doses before cold storage. These results provide the basis for the application of electron beam irradiation in the preservation of fish meat.

Key words: electron beam irradiation, Lateolabrax japonicus, myofibrillar protein, biochemical properties, circular dichroism spectroscopy