Abstract
Food and living cells are strongly affected by freezing. Ice crystal structure size in frozen food is inversely proportional to the advance rate of ice front, reflecting the important role of the molecular diffusion of water in the process of ice crystal growth. In the freezing preservation of living cells, the water permeability in the plasma membrane seriously affects freezing tolerance of cells. Plant cells, in general, have much lower water permeability in the membrane as compared with animal and microbial cells so that intracellular ice crystals are easily formed in plant cells to destroy the membrane structure. By controlling the ice crystal structure size very large, the progressive freeze-concentration becomes possible. This method is very effective to make the freeze concentration system much simpler as compared with the conventional method of suspension crystallization. The progressive freeze-concentration is expected to extend the applicability of freeze concentration widely.
