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Dr Engelbert Buxbaum
 
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wrote:

> I've dumped my microwave oven. It works by vibrating the molecules of
> food at very high frequencies. That may cause significant changes to
> the molecular structure of foods. That means that something that was
> food may be converted to molecules of substances that are not food.
> This possibility, which I don't consider to be remote, is enough to get
> me back to cooking the real way, with more naturally generated
> heatsources.


May be a little bit of very basic science will do away with such
nonsense.

Matter, including food and ourselfs, is made of molecules, which in turn
consist of atoms connected by chemical bonds. For the purpose of this
discussion you can think of atoms as tiny hard spheres, and of bonds as
springs connecting them.

If you supply energy to such a ball/spring system, you get oscillations.
Particularly violent oscillations are observed when the energy is
supplied at specific frequencies, called the natural frequencies of the
system. Even then however the spring does not break.

Heat is the movement of molecules and atoms, either oscillatory of the
bonds or random (Brownian) motion of the entire molecules. What we call
an increase in temperature is microscopically an increase in the speed
of Brownian motion and in the amplitude of intramolecular oscillations.

Heat can be added classically by a fire place, in this case energy is
supplied over a wide spectral region. Microwaves work differently in
that they add energy only at a specific frequency, which is selected to
coincide with the natural frequency of the hydrogen-oxygen bond in
water. Thus movement in water molecules is excited very efficiently, the
moving water molecules knock against other molecules in their vincinity,
transfering energy also to them.

The microwave energy however is not sufficient to break chemical bonds
(you need UV light for that), it only excites oscillations in the bond.
Hence the fears expressed above are totally unfounded.

The changes observed in boiling/steaming/microwaving are not caused by
the breakage of chemical bonds, but by the unfolding of proteins and
some polysaccharides, resulting in a more open, more easily digestible
food. That indeed is one of the main purposes of cooking: Making food
easier to digest.

In roasting on the other hand heat is applied from the surface of the
food, leading to local overheating. Under these conditions, chemical
bonds may indeed break, resulting in the formation of new compounds,
which change the colour (browning) and flavour of the food. In
moderation that is harmless and even intended, but if the food is
allowed to become too dark, carcinogenic compounds may form.

So microwaving food does not make it harmfull, on the contrary since
heating time is short, damage to heat-sensitive vitamins is limited. The
only possible damage results from microwaves escaping from the oven and
directly interacting with our body (especially the eyes). Thus microwave
ovens should be well maintained and never operated with the cover
removed.