Fig. 6 shows the unfrozen water fraction as a function of temperature for four food items during freezing. At the respective initial freezing points of each food item, the values of unfrozen fraction were at their maximum, i.e., total moisture content. As the temperature decreased, due to phase change, unfrozen water fraction reduced and the curves approached constant bound water fraction values of each food item (Hamdami et al., 2004a). These curves were used to generate piecewise equations for unfrozen water fraction during freezing, as a function of temperature. Similarly piecewise equations for ice fractions were generated. For each food item, the equations for freezing and thawing processes were developed separately. With these equations and the data fromTable 1 and Table 2, the density and the thermal conductivity values of each food item, as a function of temperature were evaluated using Eqs. (8) and (9). Depending on the process, freezing or thawing, these equations were used accordingly in the numerical simulation.