the meat (fish meat contains a small proportion of collagen, hence the special consistency).
When meat is cooked, proteins and water inside the cells coagulate, making the meat harder, but
collagen slowly dissociate in water, and produces isolated collagen molecules in water, that is
Figure 7. Cross section of meat, under the microscope. The yellow parts are mainly a solution
of proteins in water. They are surrounded by collagenic tissue (in red). Bundles of muscular
fibers are grouped in larger batches, that are themselves grouped. Collagenic tissue slowly
dissolves into water above 55°C.
But the eggs experiment now shows why beef meat cooked for very long in boiling water (poor “potau-
feu”) are so poor, with separated, hard fibres: the inside of the fibres coagulated like rubbery egg
whites, and the collagen in between dissolved slowly.
Figure 8. Boiled meat under the microscope (cross section). After some hours, fibers shrink in
boiling water, as collagenic tissue gelatinize.
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The theory also explains why it is true that meat has to be grilled very fast: reducing the cooking time
reduces the water losses. As water content is linked with tenderness and jutosity (how much juice is
released when meat is chewed), meat cooked for a short time is better than meat cooked on a slow
fire for long.
It should be also mentioned that diffusion of odorant and taste molecules into meat does not generally
occurs during cooking: meat cooked for 20 hours in a solution of fluorescein (a fluorescent yellow
pigment) is not colored at the core. Hence it is wrong to speak of “cooking by concentration”, for
roasting, as there is no concentration during this process: juice cannot come at the centre, because
there is no empty space where it could go, and water (most of the meat) is cannot be compressed. As
a consequence, there can be any “concentration” of juice, as many culinary textbook indicate wrongly.
Moreover, there cannot be any flavour concentration, as odorant and taste molecules cannot go at the