Chapter 13 - Infrared Heating of Fluid Foods

Abstract

Processing of food products generally involves heat treatment that can enhance the safety of the food but reduce organoleptic quality. A number of potential opportunities exist for exploiting the benefits of electromagnetic radiations in food processing, which include technologies like infrared (IR) heating. IR radiation is part of the electromagnetic spectrum in the wavelength range between 0.5 and 1000 mm, which is mainly utilized for food processing because of the several advantages such as higher heat-transfer capacity, instant heating because of direct heat penetration, high energy efficiency, faster heat treatment, fast regulation response, better process control, no heating of surrounding air, equipment compactness, uniform heating, preservation of vitamins, and less chance of flavor losses from burning of foods. Far-IR radiation is easily absorbed by water and organic materials, which are the main components of food, and thus offers considerable potential for efficient pasteurization. Far-IR irradiation has also been shown to be more effective in pasteurizing vegetative bacterial cells in comparison to thermal conductive heating. Moreover, Far-IR irradiation resulted in inactivation of Bacillus subtilis spores over a temperature range in which thermal conductive heating had no effect on spore viability. The various applications in food processing such as yeast reduction in honey without increasing the product temperature above 90°C and pasteurization of liquid food while maintaining the enzyme activity indicate the novel and diverse application of IR in food processing. The applicability of this technology is expected to grow as food equipment manufacturers begin to realize its full potential.