Tea processing is a traditional industry in China. In order to improve the processing quality and industrial modernization of tea, it is necessary to apply new science and technology in the primary processing industry and deep processing industry of tea, and microwave technology has a good application prospect in tea. Microwave refers to the electromagnetic wave between radio and light waves at 30MHz-300000MHz. At present, the central wavelength of microwave devices used in the food industry is 0.328m ( frequency 915MHz ) or 0.1225m ( frequency 2450MHz ). 1.Application of microwave in tea de-enzyming Green tea and oolong tea need to be de-enzymed by heating to inactivate the activity of polyphenol oxidase, evaporate part of water, volatilize the smell of grass and soften the tissue. At present, stir-frying is commonly used in production for deactivation, and steam deactivation is used in a few places.

The results showed that there was no significant difference in the quality of tea processed by microwave sterilization and stir-frying, but the time of microwave sterilization was short ( 1 / 8 of the time of stir-frying ), which could be carried out continuously. However, due to the high water content of steam and the influence of high temperature on the outer layer of raw materials, the tea after steam de-enzyming has almost no weight loss, some chlorophyll is destroyed, and the nutrients contained in the raw materials are partially lost with condensed water, and the quality is not ideal. 

The application of microwave in tea fixation is mainly due to its thermal effect. When the magnetron generates a microwave, the molecules inside the tea are affected by the periodic change of the microwave, and the periodic activity is carried out with the microwave. Due to the high frequency of microwave, the high-speed collision of the molecules inside the tea leaves produces a large amount of friction heat, which rapidly increases the temperature of the material, so as to achieve the effect of rapid heating.

The application of microwave in tea dryingIn the general hot air drying process, the material is heated externally, the surface is dried, and the heat is transferred inward, which is opposite to the direction of water diffusion transfer, affecting the outward evaporation of water. The microwave is internal heating, and the parts with high water content heat up faster. Therefore, in the process of microwave drying, the moisture migration from the inner layer to the outer layer is faster, and the drying speed is significantly faster than that of hot air drying. The application of microwave drying in tea drying has the following advantages : ( 1 ) fast drying speed ; ( 2 ) High product integrity ; because the surface temperature of tea is not too high, the chlorophyll changes less, the color is green and resistant to storage, the aroma loss is less, and the drying is uniform ; at the same time, due to the rapid evaporation of water, it is easy to form porosity, the rehydration of the product is good, and the content is easy to dissolve when making tea. 3.Application of microwave in insecticidal and anti-mildew of tea Tea is easy to produce insects during storage and transportation, and insect pollution often occurs during the pile-fermentation of dark tea. In the past, * * * fumigation was used to kill insects, but there was a problem of drug residues. Microwave treatment can achieve good insecticidal effect. The insecticidal effect of insects in tea is closely related to the dielectric properties of tea and insects. When the water content of tea is less than 12 %, it is beneficial to enhance the insecticidal effect.

Tea is susceptible to moisture and mildew during processing and storage, which reduces its quality. It is proved that microwave technology has excellent killing effect on tea mold through experiments.