Abstract: In this study, the impact of oxidative modification of hemin prosthetic group on the solubility, particle size, emulsifying activity and emulsion stability of myosin was investigated. Meanwhile, the changes in the dynamic rheological properties, gel strength, water-holding capacity, water distribution, intermolecular interaction forces and microstructure of heat-induced myosin gel were analyzed before and after the oxidative modification and the mechanism behind its effect on the water-holding capacity of heat-induced myosin gel was deciphered. The results showed that treatment with low concentrations of hemin prosthetic group had no impact on the solubility, but increased the emulsion stability, heat-induced gel strength and water-holding capacity of myosin, and made the gel network structure more uniform, ordered and compact with smaller holes in it by intermolecular interactions such as disulfide bonding. Besides, the treatment improved the surface hydrophilicity and water-holding capacity of the gel and enhanced the interaction between protein and water, consequently increasing the proportion of immobile water and retaining more water in the gel network structure. By contrast, high concentrations of hemin prosthetic group led to lower solubility, larger particle size, and worse emulsifying activity and emulsion stability of myosin, damaged the gel network structure, flattened the rheological curve, and weakened the water-holding capacity.

Key words: hemin prosthetic group; myosin gel; protein oxidation; water-holding capacity