The account of water activity in the calculation of the rate of food product shrinkage

Refrigiration treatment and storing of the food product involves its mass loss due to its drying. The loss of mass and quality of food products is determined by ambient temperature and moisture parameters and water activity of the product itself. The use of existing formulas for calculating heat and mass exchange processes of refrigeration treatment and storage of food product is limited, because they don’t lake into account water activity and its temperature dependence on this parameter. A formula has been obtained for calculating the rate of food product shrinkage, considering the hygrothermal and thermophysical properties of the product and the environment, as well as the conditions for heat and mass transfer. The technological parameter of "water activity", with the increase of which the rate of evaporation of moisture from the product surface increases linearly, has been account in this formula. For determining dependence of food product water activity on temperature range within negative meaning it is suggested to use an analogue of tissue moisture possessing properties of diluted molecular solution...