0.2.10-6 m). vi
A process of calcification takes place by the osteoblasts of the superior coat which put down
crystals of calcium along these tubes of protein. These two phenomena are continuous, there is no
difference and precise border between the calcified coat and the only protein weft. vii
In practice, the scales of fishes are mainly constituted by a network of proteins (collagen and
actine), covered with calcium. The aim of this experiment is to extract the taste and odorant molecules
produced by thermal treatment of the scales. However, the availability of these molecules is unknown.
We tried first to extract hydrophobic molecules by cooking some scales in oil. In a second time,
we cooked them in water, to extract the hydrophilic molecules. (1)
III.3.3. First test of cooking scales:
· 100 g of scales of red mullet. (3 kg of red mullet (9 fishes) give 95 g of scales).
· Sunflower oil.
· Water, salt, pepper.
· A copper pan with its lid.
1. Heat 5 mL of oil in the frying pan (without burning it).
2. Roast the red millet scales for 1 min.
3. Add 50 mL of water, salt, pepper, and cover with the lid (not to lose any molecules which could
4. Cook the mixture for 3 hours over a medium heat, with the lid.
Figure 8 : Dissolution of « cheveux d’ange »
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· At t + 1 min: before adding some water, the oil doesn’t have any taste of red millet scale. The texture
is not crispy but rubbery.
· At t + 10 min: characteristic fat smell and taste of fishes, but no particular flavour of red millet.
· At t + 20 min, t + 30 min, t + 60 min, t + 180 min: same taste, with unpleasant texture of scales. The
juice doesn’t have any significant taste.
When some scales were cooked for 6 hours, neither the scales nor the stock had any interesting
III.3.3.4. Discussion/ Interpretation:
The quantity of scales may be not important enough, but providing the restaurant in scales
becomes then a problem with regard to the numbers of red millets used.