Numerical Study on Microwave Dehydro-Freezing of Fish Tissues

In this study, a numerical simulation on the freezing process is carried out to evaluate the effects of pre-dehydration on the quality of frozen fish tissue. We use a simulation model which contains a muscle fiber to express the microscale heat and mass transfer phenomena inside the tissue cell system. Fundamental equations on heat and mass transfer are formulated in a two-dimensional coordinate system. The governing equations include phase-change terms. In order to take account of the characteristic moisture distribution produced by the microwave room-temperature drying, initial moisture distributions are given in this calculation. The numerical results indicate that the control of the water content by the pre-dehydration can shorten the freezing time. It is found that the cell shrinkage ratio is larger than that of the result using uniform distribution. As an increase of pre-dehydration, the central cell significantly shrinks but the surface-layer cell doesn’t shrink so much due to the large cooling rate.