Estimation of the temperature profile during fruit and vegetable juices freezing

The quality of food is greatly influenced by freezing rate and temperature history during freezing process. We applied unsteady-state heat conduction theory for analyzing the fruit and vegetable juices freezing process, and a cylindrical heat transfer model including phase change is developed to predict the freezing curve and changes in temperature profiles for fruit and vegetable juices, apple, orange and tomato, during freezing period. The collocation method was applied to solve the fundamental equation assuming that thermal properties of juices depended on temperature. Predicted temperature of juices was closely matched with observed data. Compared with the paper in Nippon Shokuhin Kagaku Kougaku Kaishi, 42 (12), 977 (1995) by TANAKA et al., this model could express the both freezing and thawing process. It is expected that this result would be useful for frozen food freezing operations.