The impact of varying intensity magnetic field-assisted sub-freezing preservation technology on the quality and protein structure of mutton

This study aims to investigate the impact of magnetic field-assisted sub-freezing technology on the quality and protein structure of mutton. The freezing parameters, meat quality, low-field nuclear magnetic resonance, microscopic structure, secondary structure and fluorescence intensity under different magnetic field intensities (from 0-10mT, at -7°C) were determined. The results indicated that magnetic field-assisted sub-freezing (at 2-4 mT) can preserve the quality of mutton and improve its protein properties. Compared to the control group (0mT), 2mT reduced the freezing point and supercooling point ( P < 0.05), decreased thawing loss and pressing loss and improved water holding capacity, caused minimal damage to muscle fiber structure, and prevented the degradation of the secondary structure. Moreover, under this magnetic field intensity, the intrinsic fluorescence intensity of the protein was enhanced, maintaining protein structural stability. At 4 mT, the solubility of myofibrillar proteins increased, which promoted the structural extension of the proteins and enhances the cross-linking effect of the proteins. These findings provide a scientific basis for the development of new mutton storage and freezing technology. • The magnetic field intensity of 2mt has a positive effect on mutton quality. • Magnetic field-assisted sub-freezing preserves the sensory quality of mutton. • Magnetic field-assisted sub-freezing preservation maintains protein structure.