Heat and Mass Transfer Coefficients in Food Systems

Heat and mass transfer coefficients are used in the design, optimization, operation and control of several food processing operations and equipment. They are related to the basic heat and mass transport properties of foods (thermal conductivity and mass diffusivity), and they depend strongly on the food/equipment interface and the thermophysical properties of the system. Table 9.1 shows some important heat transfer operations, which are used in food processing. In all of these operations, heat must be supplied to or removed from the food material with an external heating or cooling medium, through the interface of some type of processing equipment. Some operations, such as evaporation, involve mass transfer, but the controlling transfer mechanism is heat transfer (Heldman and Lund, 1992; Valentas et al., 1997).