Combined 0.2 T static magnetic field and 20 kHz, 2 V/cm square wave electric field do not affect supercooling and freezing time of saline solution and meat samples

Abstract

Previous studies proposed that electric and magnetic fields can affect the freezing of biological tissues, including meat. Yet, improved freezing through sole magnetic or combined electro-magnetic field exposure is disputed. Also, as previous studies typically tested very small sample dimensions, it is unclear if the reported effects are transferrable to larger product sizes that are relevant to commercial food freezing. Here we aimed at reassessing previous findings by constructing and testing a scaled-up setup for applying electric and magnetic fields during freezing. Importantly, our setup replicates key technical aspects of previous electro-magnetic freezer designs. We modeled and measured the spatial distribution of electric and magnetic fields generated by this setup. We then studied possible effects of field exposure on freezing of two different volumes of saline water and of meat. We tested four different field treatments: sole magnetic and electric field exposure, a combination of both and a control without altered field exposure. We show that the 20 kHz square wave electric field was largely homogenous, while the static 0.2 T magnetic field was not. We found that none of the field treatments altered freezing dynamics of the three tested sample types. Our findings, hence, do not support previous data obtained with similar electro-magnetic field freezer setups. We discuss how our study that uses very distinct field parameters, may inform the general discussion on the effectiveness of electro-magnetic field exposure during food freezing. • A reproducible design for electromagnetic field-assisted freezing is presented. • Freezing of saline and meat was not influenced by pulsed DC electric and/or static magnetic fields. • Generating strong, homogeneous fields poses a critical challenge to magnetic-field assisted food freezing. • Electrostatic-assisted food freezing is still in an early research state.