Effects of an oscillating magnetic field on ice nucleation in aqueous iron-oxide nanoparticle dispersions during supercooling and preservation of beef as a food application

摘要

This study was aimed to explore the effects of an oscillating magnetic field (OMF) on the ice nucleation behavior of distilled water (DW) and iron-oxide nanoparticle dispersion (IND) during supercooling. The magnetic field intensity and distribution of the OMF produced by Helmholtz coils were predicted using COMSOL. It was hypothesized that the ferric nanoparticles in the IND would promote the heterogeneous ice nucleation, and the OMF could inhibit the nucleation process by rotating the particles. The supercooling probability of IND was significantly increased by 36% under the OMF at the ambient temperature of -10 degrees C. However, the OMF also enhanced the supercooling stability of DW by 32%, suggesting that it could induce the dipolar movements of water molecules via water diamagnetism and create the induced electric fields, subsequently suppressing the occurrence of ice nucleation within DW as well. As an extended application, fresh beef was preserved in a supercooled state with the OMF treatment and its supercooled state was effectively extended for a week at the temperature of -4 degrees C. The supercooling preservation potentially prolonged the shelf life of meat with no significant changes in drip loss, color, and bacterial growth for up to a week in this study. Practical applications Recently, the application of an oscillating magnetic field (OMF) has attracted considerable interest in the food preservation industry because the OMF is supposed to control ice nucleation during the freezing process. The present study demonstrated that the OMF treatment potentially suppressed ice nucleation in water and aqueous iron-oxide nanoparticle dispersion. As a case study, beef steaks were preserved at subzero temperatures with the OMF treatment and they were successfully supercooled at -4 degrees C for up to 7 days. The supercooling technology based on the OMF allowed to maintain the meat quality for an extended period while preventing bacterial growth. This novel technology can be integrated into a commercial refrigeration system and ensure the prolonged shelf life of various food products.