Myofibrillar protein (MPS) and myosin (MS) from grass carp was irradiated by γ-ray and electron beam (EB) irradiation with different dose (2, 4, 6, 8, and 10 kGy). The changes in the physicochemical properties (solubility, Ca2+ -ATPase activity, total and reactive sulfhydryl content, surface hydrophobicity [S0 -ANS]), and structure of MPS and MS were investigated in the present work. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that there were degradation and aggregation of MPS and MS caused by irradiation, and the disappearance of myosin heavy chains (MHC) irradiated by EB was earlier than that of irradiated by γ-ray. As compared with MPS, the extracted MS was more easily destroyed. With the increase of irradiation dose, the particle size, solubility, Ca2+ -ATPase activity, and SH content of MPS and MS decreased (p < .05), while the S0 -ANS first increased and then decreased. Two-way analysis of variance results suggested that the degree of protein denaturation depends on the irradiation mode and dose. Compared with γ-ray irradiation, the EB irradiation had a greater impact on the physicochemical properties of MPS and MS.
Keywords: electron beam; myofibrillar protein; myosin; γ-ray irradiation.
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