Modelling thermal diffusivity of foods during freezing

Unlike other thermal properties, there are comparatively few methods for predicting thermal diffusivity based on the composition of the food. Instead, the most common approach is to calculate thermal diffusivity based on models for effective thermal conductivity, specific heat capacity and density using the definition of thermal diffusivity. A model of heat capacity during freezing should be able to incorporate the 'spike' that occurs at the initial freezing temperature, and results in very low thermal diffusivities. Previous work had identified that the Dul'Nev Novikov effective thermal conductivity model, Pham's ice fraction model and Chen's effective heat capacity model were effective at modelling thermal diffusivity of beef, and this approach was extended to other foods. It was found that on average this method was not as accurate for the other foods as for beef, but it was still superior to another method that has been proposed previously.