Why dielectric properties are critical in determining the rates and uniformity of heating in microwave thawing?
The dielectric properties of foods are important in understanding and modeling their behavior in radio-frequency (RF) and microwave processing, heating, and cooking of food materials. They are important because they influence the absorption of energy from the high-frequency electric fields and the conversion to heat.
What is dielectric heating of food?
Dielectric heat energy is generated in the food by molecular friction as high-frequency electric fields alternate. Unlike conventional heating, dielectric heating is fast and volumetric. RF processing can be used to process any dielectric material and most food products are dielectric.
What is dielectric heating effect?
Dielectric heating occurs when high-frequency electromagnetic radiation stimulates the oscillation of dipolar molecules (e.g., water molecules) in the surrounding medium at a very high speed, thereby converting electromagnetic energy into kinetic energy.
What is the mechanism of microwave heating?
Microwave Oven generates electromagnetic waves(called microwaves), which makes water move. Microwave causes molecules to vibrate. Vibration creates friction. Friction produces the heat that cook the food.
How does dielectric heating work?
Dielectric Heating is a process of electric heating by which the temperature of a dielectric (non-conducting) material is raised by the application of an alternating electric field (high voltage ac signal). The increase in temperature results in heating the substance which is in contact with the external field.
What is microwave dielectric heating?
Dielectric heating, also known as electronic heating, radio frequency heating, and high-frequency heating, is the process in which a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation heats a dielectric material.
What material is dielectric heating?
In dielectric heating, the energy of high-frequency alternating electromagnetic field is transferred to polar materials, such as water (dipoles) inside muscle tissue, to produce thermal energy. Dielectric heating includes both radio frequency (RF) and microwave (MW) heating.
What are the disadvantages of dielectric heating?
Disadvantages of Dielectric Heating :
- It is not possible to increase the supply voltage beyond the breakdown of the dielectric material.
- it is not possible to increase the frequency of ac source beyond the resonant frequency of the electrodes and the capacitor formed by the electrodes and job.
How microwave heating is different from conventional method?
Microwaves ovens use electromagnetic energy and generate electromagnetic waves that heats up the food kept in the appliance. Unlike a conventional oven, they do not heat up the whole space inside the appliance and just use the waves to heat the food kept in it.
What is dielectric heating advantages of dielectric heating?
Advantages of Dielectric Heating : The heating is uniform. It is possible to control the heat automatically. There are no-products of the heating process. The process of heating is free from gases and ash. It is possible to achieve high rate of heating.