ENGINEERING PROPERTIES IN FOOD-PROCESSING SIMULATION

The design, simulation, optimisation and control of food processing op erations require basic engineering properties of foods. Due to the com plex physical and chemical structure of foods, theoretical prediction is not possible, and experimental data are needed for the thermophysic al, transport, and mechanical properties of raw and processed food pro ducts. Special consideration is necessary for the quality changes, mic robiological/biological safety, and sanitation of food processing. Tab les of scattered data and limited databases have been published, but t here is a need for more reliable data and models, especially for the t ransport properties, i.e. the fluid now, heat and mass transfer proper ties of food products. Typical experimental values and semi-empirical models for the mechanical properties, the apparent viscosity, the ther mal conductivity, and the moisture diffusivity are presented for model foods and fruit/vegetable products. Application of the engineering pr operties to the simulation of food processing operations, such as ther mal processing and drying, is discussed. Reliable pilot-plant and indu strial data are essential, since some engineering properties, such as interphase transfer coefficients and fouling factors, are affected str ongly by the food product/processing equipment system.