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Which kitchen does not possess
a microwave oven today? It heats that cup of milk, cooks a tasty snack
or thaws out the chicken earmarked for Sunday lunch.
A relatively recent development, the microwave oven is widespread in
European households. In an environment of social change, where working
women spend less time preparing meals, the microwave oven is a welcome
solution. As well as conventionally made meals, it cooks the plethora
of ready-to-eat foods now available on the market. Although a fairly
modern invention, the microwave is now a familiar appliance.
How does it work?
Microwaves form part of the electromagnetic spectrum, and their
frequency is situated between infrared waves and radio and television
waves. Scientists during World War II realised that these microwaves
then used in communication systems had other uses. Since then, the early
technology has been transformed into the modern, sophisticated kitchen
appliance.
In an oven cavity, a magnetron transforms electrical energy at low frequency
into high frequency microwaves and sends this concentrated energy down
a waveguide, which enters the food. The energy makes the water molecules
in the food vibrate at 2.5 billion times a second and heating occurs
due to rotation of the water molecules.
Heating Instructions
Don't forget, as wiith all food preparation, whether conventional or
microwaved, you should follow heating instructions on the food packaging
and ensure that the food is thoroughly cooked. The depth to which microwaves
penetrate a food differs depending on its density. For example, foods
like minced beef or pureed potatoes cook faster than denser foods such
as steak or whole potatoes. Sometimes microwaved food has hot and cold
spots; this is because energy distribution is uneven. Mode stirrers
or turn tables in the oven help improve the energy distribution in the
food.
Microwaves cook food from the outside to the centre. Small food items
cook faster than large ones. For this reason, thicker or denser portions
of food should be placed to the outside of the cooking dish with thinner
less dense ones placed on the inside. One item cooks faster than several.
The explanation is that when the energy is divided among several foods
the cooking time is longer.
What about vitamins and minerals?
Vitamin retention in some cases of microwaved foods can be even better
than in conventionally cooked foods. This improvement is due to the
higher energy levels and thus shorter cooking time required in a microwave
oven. Minerals cannot be destroyed during food treatment, they can however,
be lost in cooking water or meat juices. Studies of a variety of vegetables
cooked conventionally, and in a microwave oven, for various lengths
of time, revealed a negligible change in mineral content regardless
of cooking method. (1) Cooking in microwave ovens is safe; it saves
on energy and time. A high tech. research result is now a common household
technology!
Source
Eufic 1999
(1) ILSI Concise Monograph, Microwave Ovens, 1998  |
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