FOOD 2010 Lecture Notes - Lecture 9: Wind Chill, Microwave Oven, Food Engineering
19 Dec 2016
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Document Summary
Heat transfer is very important because major processing operations are baed on heat transfer principle. Involves adding adding heat energy to goos to increase the temperature. Energy cannot be created or destroyed, it can only be converted into other forms of energy. Converting radiant energy from the microwave region of the electromagnetic spectrum to kinetic energy in water molecules. Dipolar nature of water molecules enables the molecule to absorb microwave energy. When food is place between 2 electrodes, an electric eld is created when the microwave oven is in operation. Polar molecule align themselves within the electric eld. When the polarity of the eld is alternated millions of times, water molecules spin (involving kinetic energy), causing friction which is manifested as heat. Most e ective for highly polar molecules such as water. Volume heating is the term used to describe microwave heating because heat develops from the interior of the food (not just the outside, inward.
