What is the mechanism of microwave heating?

The principle of microwave cooking is conversion of electromagnetic energy into thermal energy within meat . During cooking, microwave energy is absorbed by rotation of water molecules and translation of ionic components in meat; the water content and the dissolved ion content are, therefore, important factors.

Microwave heating effects work by four major mechanisms, namely dipolar polarization (rotation of dipoles), ionic conduction (ionic polarization), electronic polarization (atomic polarization), and interfacial polarization (surface polarization) as shown in Fig. 6.

The magnetron generates microwave radiation by bouncing electrons around inside a vacuum filled cavity that is exposed to a strong magnetic field . This magnetic field forces these electrons to circle around inside the cavity, absorbing energy. Eventually, this energy is released as a microwave.