1. Reasons for uneven microwave heating:

(1) Microwave heating is selective. Even in the same microwave field, different ingredients have different temperature rises.

(2) Microwave has good penetrability and is affected by reflection, penetration, refraction and absorption in actual heating, even though the heat energy generated by different parts of the same food may be very different;

(3) The sharp concentration of electric field, some of which are also called edge effect. As a kind of electric wave, microwave has sharp electric field concentration, which is the main reason for the uneven heating of food by microwave. The electric field will be concentrated in the corners, and these parts will generate more heat and heat up quickly. In order to overcome the shortcomings of water chestnut effect and hot spot, many improvements have been made to the container. For example, try to use round containers and ring containers with appropriate sizes. Plastic treatment of sharp food. In order to overcome the limitations of microwave heating, it has become a new trend to combine microwave and far infrared heating methods.

(B) the impact of microwave on the human body

According to the principle of microwave, the human body will also absorb microwave, so microwave radiation will also cause some harm to the human body. Usually, when the human body is irradiated, the skin always feels hot first, so it can be avoided in time. However, when exposed to microwave radiation, because of its penetrability, the tissues in the body will also heat up at the same time, and there are fewer nerves in the human body, so those organs with low heat resistance have been damaged before they feel the heat. For example, blood vessels, eyes and testicles are vulnerable to microwave damage, and common diseases of radar workers include cataract and male infertility. Pay attention to safety when using microwave, but don't be too nervous as when treating radioactivity.

(3) microwave sterilization and bag breaking

In the process of microwave sterilization, in addition to paying attention not to use metal containers and aluminum-plated or aluminum-coated bags, there is also the problem that the sealed bags are broken during sterilization, which is difficult to solve. The seal is not good after sterilization. At present, microwave sterilization can be carried out before packaging or after packaging. When the packaged food is sterilized by microwave heating, because the pressure in the bag is too high, the packaging bag will burst, so the whole process of microwave heating sterilization should be carried out under pressure, or the discoloration of the package (4) should be treated in a pressurized glass container.

In the microwave sterilization of mustard tuber and other products, the discoloration of mustard tuber products was also found.