Studies on the application of microwave vacuum technology for food processing

Microwave heating is characterized by rapid heating, the selective heating of water and energy savings. The author has investigated the development of new processes for the drying of fruits and vegetables using microwave technology. In a series of studies, it was found that pre-freezing, which converts sample moisture to ice crystals and damages the tissue structure, further improves the drying efficiency of microwave-vacuum drying, suppresses sample shrinkage during drying and produces porous dried materials similar to freeze-dried products. This porous structure is effective in improving the texture, the water absorption rate of dried products and the efficiency of the milling process in powder production. Furthermore, the author confirmed the conditions under which the sample temperature can be maintained at a constant level throughout drying by controlling the microwave power output, and the relationship between temperature and the quality characteristics of the dried product. Drying technologies that exploit microwave properties show potential for future development and will lead to the effective and energy-saving use of untapped food resources in agricultural production.