Effect of Herring Antifreeze Protein Combined with Chitosan Magnetic Nanoparticles on Quality Attributes in Red Sea Bream (Pagrosomus major)

The effects on the quality of frozen red sea bream which were pretreated by soaking in solutions containing trehalose, chitosan magnetic nanoparticles (CS@Fe3O4 nanoparticles), and glycerin or different concentration herring antifreeze proteins (AFPs) were investigated in this study. The DSC, dynamic rheology, shear force, and TPA were conducted to analyze the physical characteristics. Raman and intrinsic fluorescence spectra were used to measure the protein secondary and tertiary structures. So-ANS and zeta potential were carried out to explore the degree of protein aggregation. Low-field NMR was used to test the water migration, and light microscope was performed to observe the fiber microstructure. Results showed that prior to freezing, the pretreatment of red sea bream samples with soak solutions could minimize drip loss, preserve the meat tenderness and texture, and improve the fish fillet thermal stability and viscoelasticity, and the free water content was decreased while the immobilized water content was increased; the longitudinal and transverse fiber structures were clear and less destructive. Compared with the control, the protein secondary and tertiary structures of samples, among the tested soaking solutions, tended to stability, and the degree of protein oxidation and aggregation was decreased. Therefore, this methodology was proved to be an effective method to inhibit the ice crystal growth and modify ice crystal form in order to improve the quality of the final product, and these effects were amplified with the concentration of AFPs increasingly.