The results of a short study by us on the affect of freezing garlic with the assistance of an oscillating weak magnetic field has just been published in the Food and Bioprocess Technology journal.

James, C., Reitz, B., G. & James, S. J. (2014) The freezing characteristics of garlic bulbs (Allium sativum L.) frozen conventionally or with the assistance of an oscillating weak magnetic field.  Food and Bioprocess Technology.  Vol. 8:3, pp702-708.

Several novel freezing systems have been developed that claim to improve the quality of frozen foods by controlling ice crystal formation through enhancing super-cooling in the food prior to ice nucleation. One of these is the Cells Alive System (CAS) produced by ABI of Japan, which applies oscillating magnetic fields (OMF) during freezing.  We have an ABI CAS freezer at the Grimsby Institute and our paper describes a short study we carried out to investigate what effect freezing under OMF conditions had on the degree of super-cooling and characteristics of the freezing curve of individual cloves within whole garlic bulbs when compared to freezing under the same conditions without OMF. Garlic (Allium sativum L.) was chosen as the test material since a previous study has shown it to significantly super-cool during conventional freezing. Overall, these results clearly indicate that:

1. (1)significant super-cooling occurred in garlic bulbs during freezing under some of the freezing conditions used in these trials;
   

2. (2)freezing under the OMF conditions used in these experiments had little significant additional effect on the freezing characteristics, or degree of super-cooling, of garlic bulbs, in comparison with freezing under the same environment without OMF;
   

3. (3)super-cooling is more likely to occur in garlic bulbs frozen from an initial ambient (21 ± 1 °C) state than those frozen from an initial chilled (4 ± 0.5 °C) state.
   

Our results (and similar studies by Suzuki et al. (2009) and Watanabe et al. (2011)) do not appear to support the patent claims (Owada and Kurita 2001; Owada 2007) that OMF-assisted freezing enhances super-cooling in foods during freezing. In our opinion, this does not, invalidate ABI’s CAS system as a method of enhancing the overall freezing of foods; however it does suggest that weak OMF may not affect all foods and that any effect will depend on a complex combination of food, freezing rate and magnetic field frequency.

This short communication is one of a series of publications planned this year from FRPERC on different aspects and technologies for improving food freezing.  This work has been funded by Air Products and we would like to take the opportunity to thank them for their funding and support.

For more information about freezing topics please visit our new Freezing page.

If you would like to know more about this work please contact Christian James: jamesc@grimsby.ac.uk.