41
EN
The advantages of microwaves
In conventional ovens, heat radiated by electrical
elements or gas burners slowly penetrates the
food from outside to inside. On account of this
there is a major amount of energy is wasted
heating the air, the oven components and the food
containers.
In a microwave oven, heat is generated by the
food itself and the heat travels from inside to
outside. No heat is lost to the air, the walls of the
oven cavity or the dishes and containers (if these
are suitable for use in microwave oven), in other
words, only the food is heated.
Microwave ovens have the following advantages:
1. Shorter cooking times; in general these are
up to 3/4 less than the time required for
conventional cooking.
2. Ultra-fast food defrosting, thus reducing the
danger of bacterial development.
3. Energy savings.
4. Conservation of the nutritional value of foods
due to the shorter cooking times.
5. Easy to clean.
How a microwave oven works
In a microwave oven there is a high tension valve
called a magnetron which converts electrical
energy
into
microwave
energy.
These
electromagnetic waves are channelled to the
interior of the oven through a wave guide and
distributed by a metallic spreader or through a
turntable.
Inside the oven the microwaves propagate in all
directions and are reflected by the metal walls,
uniformly penetrating the food.
Why food heats up
Most foods contain water and water molecules
vibrate when subjected to microwaves.
The friction between molecules produces heat
which raises the temperature of the food, de-
freezing it, cooking it or keeping it hot.
Since the heat arises inside the food:
•
This can be cooked with little or no liquid or
fats/oils;
•
De-freezing, heating or cooking in a
microwave oven is quicker than in a
conventional oven;
•
The vitamins, minerals and nutritional
substances in the food are conserved;
•
The natural colour and aroma of the food are
unchanged.
Microwaves pass through china, glass, cardboard
or plastic but do not go through metal. For this
reason, metal containers or ones with metal parts
must not be used in a microwave oven.
Microwaves are reflected by metal...
... but go through glass and china...
... and are absorbed by foods.
Summary of Contents for EMWK 1050.1E
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