Elements of a low-temperature processing system

Low-temperature processing of food materials is a critical unit operation in terms of preservation and pretreating for further processing. Depending on the types of product and equipment, conductive and convective heat transfer, coupled with mass transfer by means of evaporation, occur in the sample during refrigeration. Mechanical refrigeration is the most widely used approach for low-temperature processing that is either applied by vapor compression or absorption cycle systems in common. Mechanical equipment of refrigeration systems comprises a compressor, condenser, expansion unit, and evaporator in assistance with other operational elements. Type of refrigerant that is used for cooling the systems is of crucial importance due to safety and energy efficiency concerns. Depending on the technological developments and innovative designs, refrigeration systems continuously evolve and develop to fulfill the requirements of food industry or in household usage by individuals. In this chapter, basics of refrigeration systems and recent developments were assessed.