Engineering properties in food processing simulation

The design, simulation, optimisation and control of food processing operations require basic engineering properties of foods. Due to the complex physical and chemical structure of foods, theoretical prediction is not possible, and experimental data are needed for the thermophysical, transport, and mechanical properties of raw and processed food products. Special consideration is necessary for the quality changes, microbiological/biological safety, and sanitation of food processing. Tables of scattered data and limited databases have been published, but there is a need for more reliable data and models, especially for the transport properties, i.e. the fluid now, heat and mass transfer properties of food products. Typical experimental values and semi-empirical models for the mechanical properties, the apparent viscosity, the thermal conductivity, and the moisture diffusivity are presented for model foods and fruit/vegetable products. Application of the engineering properties to the simulation of food processing operations, such as thermal processing and drying, is discussed. Reliable pilot-plant and industrial data are essential, since some engineering properties, such as interphase transfer coefficients and fouling factors, are affected strongly by the food product/processing equipment system.