Abstract: The effects of magnetic field (MF)-assisted freezing at different intensities (0, 1, 2, 3, 4, and 5 mT) on the physicochemical properties and structure of myofibrillar protein (MP) from prepared chicken breast were investigated in terms of secondary structure, surface hydrophobicity, solubility, and degree of oxidation. The results showed that compared with the control group, the solubility of MP in all MF treatments significantly increased, while the turbidity, surface hydrophobicity, and average particle size significantly decreased (P < 0.05). Additionally, all MF treatments significantly increased the absolute value of the zeta potential of MP relative to the control group, enhanced the surface charge density, and consequently inhibited the growth of heterogeneous aggregates in MP solutions. The results of circular dichroism (CD) spectroscopy revealed that MF treatments increased the content of α-helix, inhibited the unfolding of protein structure, and reduced the exposure of internal groups. Concurrently, MF treatment at 3 mT significantly reduced the generation of carbonyl compounds (P < 0.05), reflecting the inhibition of oxidative modification and abnormal cross-linking of MP. Overall, 3 mT MF-assisted freezing had a significantly positive effect on preserving the structure and physicochemical properties of MP from prepared chicken breasts and further improved its processing quality.

Key words: prepared chicken breast; magnetic field-assisted freezing; myofibrillar protein; protein structure; physicochemical properties