Influence of radiation types and doses on the structure and functionality of myofibrillar protein

Irradiation can affect structure of proteins in food, and according to radiation type and dose, protein modification is differently induced, which might positively influence their functionality. Thus, the objective of this study was to demonstrate the effects of the radiation type (gamma rays, X-rays, and electron beams) and dose (2.5, 5, and 10 kGy) on the conformation and functionality of myofibrillar proteins (MP). Upon irradiation, hydrophobic interactions and covalent bonds between MP molecules increased, thereby increasing viscoelasticity and decreasing protein solubility. Among the irradiated MP, solubility of 2.5 kGy gamma ray-irradiated MP (5.65 mg/mL) was higher than MP irradiated with other source and dose. Soluble MP parts after irradiation comprised smaller, more stably dispersed particles with low molecular weight proteins than those in non-irradiated MP. The 10 kGy electron beam-irradiated MP showed significant changes in secondary structure, resulting in high surface hydrophobicity and foaming properties. Meanwhile, 2.5 kGy gamma ray irradiation improved the emulsifying capacity of MP due to its high solubility. Thus, irradiation can improve the functionality of MP by inducing conformational changes, and especially gamma ray at 2.5 kGy is most suitable processing condition for protein utilization.