1) to avoid the formation of large ice crystals between cells.

2) reduce the extravasation of intracellular water and reduce the loss of juice during thawing.

3) The contact time of concentrated solute in cell tissue with food tissue, colloid and various components is obviously shortened, and the harm of concentration is minimized.

4) rapidly lowering the food below the temperature of microbial growth activity is beneficial to resist the growth of microorganisms and their biochemical reactions.