Mr. JOY ultra sound assisted freezing will be destroying the cell structure and there by can decrease the freezing time by a few minutes.. but as you go for higher frequency it may also give adverse effects. you may also take care of the type of instrument (bath or probe type) that you are using. decreasing the pulsuation can also help to improve your results.
Are you talking of the use of ultrasound as a pre-treatment or as an adjunct to the freezing process?
I'm not sure of its usefulness as a pre-treatment, but there is some evidence of it potentially being an aid during freezing. In theory, the ultrasound creates cavitation bubbles throughout the product, which promotes more even ice nucleation and fragment ice crystals already present into smaller crystals. It may also accelerate convective heat transfer in the cooling media thus speeding up the freezing process. A study by Delgado et al. (2009) on apple cylinders reported an 8% increase in freezing rate when used.
Delgado, A. E., Zheng, L. & Sun, D.-W. (2009) Influence of ultrasound on freezing rate of immersion-frozen apples. Food and Bioprocess Technology, 2:3, 263-270.
i think as ultrasound waves have heating effect it will have adverse effect on freezing.
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