just like you coagulate egg whites.
But remember that meat is muscular tissue, i.e. a specific part of the body of an animal which has the
ability to contract when the brain issues orders to do so. This contraction is being done by the proteins
in the fibres, and it causes the fibres to shorten.
But also remember that water cannot be compressed! This phenomenon is the basis of the hydraulic
elevator in garages and it is a major difference between gases and some liquids.
II - 3 (of 9)
Use two balloons. Blow air in one, and tie it, and pour water in the other, and tie that one as well.
Try pressing the balloon full of air: you can reduce the volume of this balloon.
Now try pressing the second balloon, and you see that you cannot reduce the volume. The
compressibility of water is very small!
Never forget that food is often primarily made of this non compressible water!
Coming back to meat, if muscles can contract, i.e. shorten, it also means that the total volume is
conserved during contraction, and indeed you can see that bicep muscles that contract increase in
width at the same time: the total volume is conserved.
But it also means that muscular fibres should not be too fragile: the “envelope” of these fibres is made
of a resistant material, called “connective tissue”. What is the nature of this tissue? You are now
familiar with proteins… and indeed this muscular tissue is made of proteins of a special kind: collagen.
Collagen? You know it well - when meat is heated in water, it makes a stock that can jellifies later
upon cooling. The jellification of the stock is because this stock contains gelatine that has been
extracted from collagen that has been dissociated during cooking.
And the colour? Sometimes meat is red: we know that it is because of blood, which is a red colour
because proteins containing iron called haemoglobin. Blood is inside meat, but limited to the blood
vessels. A good demonstration for this fact is shown by soaking meat in water: you see that the water
turns red, as the blood dissolves in it; but at the same time, the meat turns white.
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