Microwave Ovens: Domestic and Industrial

Microwave could go through food materials to provide volumetric heating. Compared with traditional heating methods transporting energy through temperature gradient, microwave heating overcomes the low heat transfer rate due to the low thermal conductivity of food materials. As a result, microwave has been widely used in heating foods both for household and industrial applications. The design of domestic microwave oven has been mature, which contains a 2450 MHz magnetron and a multi-mode resonant cavity. The size of the resonant cavity in each dimension is much longer than that of the microwave wavelength. For industrial application, 915 MHz microwave generators are always equipped on the heating system, which brings deeper penetration depth. For continuous production of suppressor is indispensable to keep food products continuously load and unload. Industrial microwave heating systems have been successfully used in drying and thawing processes to shorten processing time, reduce energy consumption and improve processing quality. However, in thermal processing, such as pasteurization and serialization, the industrialization of microwave heating is in progress. Numerous problems concerning microbial safety of microwave thermal processing have been fixed. The major drawback of microwave heating either for domestic or industrial application is the non-uniform heating, which is dominated by the electric field distribution. For domestic microwave oven, edge heating brings the major non-uniform heating. Microwave with lower frequency is more suitable for large scale industrial microwave heating system. Microwave thermal processing for producing high quality convenient food products is a promising technology in food industry.