Whether it is vegetable packets in instant noodles, healthy and delicious dried fruit, or nutritious and convenient fruit cereal, the dehydration and drying process of vegetables and fruits are indispensable.
Microwave drying equipment, also known as microwave sterilization dryer, is a kind of used to dry food, medicine, wood, building materials, cardboard, and other microwave machines. Compared with traditional drying equipment, microwave drying equipment is characterized by fast drying speed, high efficiency, environmental protection, and energy-saving, and is a new type of equipment in response to the low carbon economy.
Microwave fruit and vegetable drying equipment have significant advantages:
1. The microwave drying equipment for fruits and vegetables has a fast drying speed: Microwave makes the fruit and vegetable inside and outside at the same time heat, only need a few minutes to a dozen minutes can dry, the dehydration rate is fast, and the efficiency is extremely high.
2. Microwave drying equipment works efficiently: Material inside and outside at the same time heating, and can do 24 hours continuous processing, large production scale.
3. High-quality product: Regardless of the shape of the fruit and vegetable, microwave makes it inside and outside at the same time uniform penetration of electromagnetic waves to generate heat, unrestricted，so the heating is more uniform, will not appear outside the phenomenon of dry inside wet.
4. Destroy and inhibit bacteria: Under the dual action of biological effect and non-biological effect of microwave heating, the survival and reproduction of microorganisms are inhibited. Dried fruits and vegetables will have a longer shelf life, expanding food manufacturers’ profit margins.
5. Low drying temperature: low temperature and rapid drying process can maintain the color and quality of vegetables, and maintain the nutrients and beautiful appearance of vegetables.
6. The overall appearance of microwave drying and dehydration equipment adopts 304 stainless steel material, with compact structure, beautiful and smooth lines, and small floor area, which can save the site.
7. Customized service for vegetable drying machine can design reasonable parameters according to the physical characteristics of materials.
8. Microwave penetration avoids heat transfer and reduces heat consumption, and drying energy consumption is usually reduced by more than 50%.
9. After the fruits and vegetables are dried in the closed space to avoid the secondary pollution and the microwave sterilization, the hygienic index completely conforms to the national food hygienic standard.
Characteristics of microwave heating and drying:
The microwave’s basic properties are generally shown as three characteristics of transmission, reflection, and absorption. Water and food will absorb microwaves and make themselves hot.
Microwaves have longer wavelengths and better penetration than other electromagnetic waves used for radiative heating, such as infrared and far-infrared.
When microwaves penetrate into the medium, the internal and external parts of the dielectric material are heated almost simultaneously, reaching the state of body heat source, which greatly shortens the heat conduction time in conventional heating.
2.The selective heating.
The ability of a substance to absorb microwaves is mainly determined by its dielectric loss factor. Because the loss factor of each material is different, microwave heating shows the characteristic of selective heating. Water molecules are polar molecules with large dielectric constant and dielectric loss factor. They have a strong absorption ability to microwave.
However, the dielectric constant of protein-carbohydrate is relatively small, and its microwave absorption capacity is much smaller than that of water. Therefore, the amount of water content on the microwave heating effect has a great impact on food.
3.Low heat inertia
Microwave heating of dielectric material is instantaneous heating, low energy consumption. On the other hand, the microwave’s output power can be adjusted at any time, and the medium temperature can be changed without inertia. There is no residual heat phenomenon, which is suitable for automatic control and continuous production.
Principle of microwave heating and drying:
Microwaves are radio waves with frequencies ranging from 300 MHZ to 300 GHZ. Water molecules in the heated medium are polar molecules. Under the action of the fast-changing high-frequency magnetic field, its polarity orientation will change with the change of the external electric field. Cause the effect of molecular mutual friction.
At this time, the field energy of the microwave field is transformed into the heat energy in the medium, making the material temperature rise and achieving the purpose of heating and drying. Microwave energy is usually obtained by direct current or 50Hz alternating current through semiconductor devices or vacuum devices. At present, magnetron and klystron are mainly used in microwave heating, especially in industrial applications.
Microwave dehydrating and drying equipment for fruits and vegetables have high production efficiency and excellent product quality. It can effectively save site cost, labor cost, equipment, daily maintenance cost, etc. Microwave equipment, such as microwave puffing equipment, microwave baking equipment, and so on, is a cost-effective investment. Once purchase, lifelong benefit, is the size of the food processing plant quality of choice.