The impact of static magnetic field-assisted immersion freezing on the structural and functional properties of myofibrillar proteins in golden pompano (Trachinotus ovatus) during frozen storage.

Refrigerator freezing (RF), immersion freezing (IF) and static magnetic field-assisted immersion freezing (MIF) were employed on golden pompano (Trachinotus ovatus), and the structure and functional properties of golden pompano myofibrillar proteins (MPs) during frozen storage were investigated. The results showed that the α-helix content, endogenous fluorescence intensity and total sulfhydryl content of the MIF samples during frozen storage were higher than those of the other frozen samples (P < 0.05), indicating that MIF treatment inhibited the disordered protein structure changes and oxidation in protein caused by frozen storage. The emulsification properties showed that the MIF group formed and maintained the finest emulsion droplets during frozen storage. The low-field nuclear magnetic resonance (LF-NMR) results revealed that the immobilized water content (P21) of the MIF myofibrillar protein gel was 1.25 % and 2.48 % higher than that of the IF and RF samples after 180 days of frozen storage. These findings demonstrated that the MIF treatment contributed to the full swelling of MPs to form a dense gel structure, efficiently trapping water. In general, MIF could suppress the structural changes in myofibrillar proteins and the decrease the emulsification and gel properties of golden pompano caused by frozen storage.