ABSTRACT
The thermal conductivity of foods is affected by three factors: composition, structure, and processing conditions. Water content plays a significant role due to the relative magnitude of conductivities of water in foods. The nonaqueous part of food such as fats and oils also plays an important role in fatty foods. The structural factors consist of porosity, pore size, shape and distribution, and arrangement or distribution of different phases, such as air, water, ice, and solids. The processing factors consist of temperature, pressure, and mode of heat or energy transfer (Sablani and Rahman, 2003). Thermal conductivity values of food materials could vary up to two orders of magnitude; thus, prediction is highly complex in a generic approach. Thermal conductivity prediction models can be grouped as (1) theoretical-based models, (2) models based on distribution factors, (3) percolation theory, (4) effective medium theory, and (5) empirical-based models.
