Effect of permanent magnetic fields on freezing characteristics of agar gel and potato

The application of magnetic field in food freezing has shown potential to improve freezing characteristics and product quality; however, findings remain inconsistent across studies. This study investigated the effects of a permanent magnetic field (PMF) with different magnetic flux densities on the freezing behavior of agar gel and potato samples. Three PMF treatments at 5.8, 14.7, and 25.0 mT were produced by ferrite magnets, and their field strength and distribution were predicted through numerical simulations. In agar gel samples, the degree of supercooling slightly increased with higher PMF strength; however, this effect was limited to the specific freezing condition (0.04 °C min⁻¹ at -20 °C) and no noticeable microstructural changes were observed. Moreover, PMF treatments did not affect the freezing behavior of potato samples and their quality attributes. These findings indicate the limited contribution of PMF treatment for improving freezing performance in food systems under the tested conditions.