Predicting Temperature vs Time Behavior During the Freezing and Thawing of Rectangular Foods

Abstract

Based on the effective heat capacity characteristics of biological materials during freezing we have derived a short-cut equation for predicting their temperature vs time behavior during freezing and thawing. The equation can be used in the low Biot number range for rectangular bodies with similar or dissimilar heat-transfer coefficients at their different surfaces. It has been experimentally and numerically tested for rectangular blocks of chopped beef with two or four exposed sides for Biot numbers ranging between 0 and 3. In this range it predicts temperature vs time behavior with errors of less than 5 to 10% in terms of overall processing time. By using numerical methods, the approach used can be extended to handle problems involving time-varying boundary conditions and many types of non-linear, physical-property behavior.