Freezing is one of the important methods of food preservation. Frozen meat, fish, vegetables, fruits, butter, etc. are commonly used raw materials in many food processing industries. With the exception of some frozen desserts, frozen foods need to be thawed and warmed before consumption. For consumers, thawing is a relatively simple process and is not difficult to carry out. For example, frozen vegetables can be heated directly in boiling water, and fish pieces can be fried or chopped before thawing. For processors, thawing is a time-consuming and laborious process and is considered the reverse process of freezing. The traditional thawing method is that heat acts on the surface of the frozen product and then slowly conducts it to the inside of the product. The melted surface has poor thermal conductivity and the temperature inside the product rises very slowly. The result is a long melting cycle, quality deterioration, and increased juice loss. ; In addition, bacteria are likely to breed during the thawing process. The rise in temperature of the product during thawing first occurs on the surface. At this time, bacteria on the surface will multiply rapidly after being heated.

Microwave thawing means that the temperature of the product is raised from the frozen storage temperature to a higher temperature but still below the freezing point, rather than rising to ambient temperature. At this time, the product is no longer a frozen solid and can be used for processing and cutting operations. When thawing meat products using microwaves, the temperature in the center will not exceed -2~-5°C. Once this temperature is exceeded, the surface of the product will inevitably be overheated. However, under temperature conditions, the product is easily punctured, and the center part can be easily melted with hot water. Also called "semi-thaw". Microwave thawing of food can shorten processing time, reduce the total number of bacteria and improve quality. It usually takes a few hours for a frozen chicken to thaw at room temperature, but only a few minutes in the microwave. Using a 2450 MHa microwave, a 7.5cm thick piece of fish meat is heated at -29°C and can be defrosted in just 2 minutes.

Therefore, microwave thawing technology is of great significance for shortening food preparation time and improving production efficiency.