Saturday, May 31, 2008

Microwave Processing – How it works?

Microwave Processing – How it works?
Introduction
Microwave energy, usually generated by a magnetron, occurs as alternating current at either 915 or 2450 megahertz. Both frequencies are authorized by the federal government for use with microwave ovens. Because water molecules are polar (have positive and negative ends), they tend to oscillate as they try top align themselves alternately between the positive and negative charges of the microwave energy.

Function
When the frozen foods are exposed to microwave energy, the liquid water in them (all frozen foods contain some water in the liquid stat) begin to heat due to the friction created by high speed oscillations of the water molecules. Most of the water in frozen foods is in the ice state and is not affected by the microwave energy, until heat generated by liquid water molecules is conducted to the ice, melting it, and thereby producing more liquid water to become involved in the heating process.

History
The first application of microwave energy in industry occurred during the 1070s when cooperative experiments between the Gloucester Laboratory, a USDC facility, and the Raytheon Co. resulted in the introduction of a continuous microwave tunnel in the seafood industry, for thawing or tempering of shrimp and fish blocks. In tempering, the product is not quite thawed yet lends itself to further processing such as cutting or coating with a breading. Microwave Processing – How it works?

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