FLUIDIZATION AND ITS APPLICATIONS TO FOOD-PROCESSING

This paper is a comprehensive review of the science behind fluidization of food materials, and its applications in food processing. Fluidization is a process by which a bed of particulate materials exhibts fluid-like behaviour as a result of fluid flowing through it. Fluidization can be carried out by liquids or gases and different forms of fluidization occur depending on the type of fluidizing medium and the properties of the particulate material, this can have an important effect on the type of processes that can be carried out using fluidization. Typical food processing applications of fluidization include freezing and cooling, drying, puffing, freeze drying, spray drying, classification and blanching and cooking. These processes involve heat and mass transfer to or from the food material, which can be rapidly achieved from fluidization. Food particles are porous and the intra-particle resistances to heat and mass transfer are usually much higher than the resistance offered by the fluidizing medium. Hence fluidized beds can also be used to determine intra-particle resistances which can then be used to relate to food structure.