ZANUSSI
4
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.
