Chemical Engineering Research & Design, Vol.81, No.9, 1129-1135, 2003
Experimental data and modelling of ice cream freezing
In order to optimize the ice cream industrial freezing process, a thermal model has been developed to predict the freezing times. First, physical relationships based on experimental determinations have been validated to interpret the principal ice cream thermal properties involved, namely the specific enthalpy and the thermal conductivity, as a function of the temperature and the density of the product. This theoretical freezing model, based on the numerical resolution of the heat equation, includes both the freezing conditions-ice cream initial temperature, nature of the cooling medium and cooling rate-and the sample composition. Experimental temperature profiles obtained with different freezing conditions were used to validate the model and assess its accuracy. The effect of the freezing conditions on the ice crystal texture was studied. It was shown that the most important operating parameters were the freezing rates and the freezer temperature that govern not only the size but also the ice crystal morphology.