The Freezing Characteristics of Garlic Bulbs (Allium sativum L.) Frozen Conventionally or with the Assistance of an Oscillating Weak Magnetic Field

Abstract

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. This short study was 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) significant super-cooling occurred in garlic bulbs during freezing under some of the freezing conditions used in these trials; (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 and (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.