Молекулярная гастрономия для креативных шеф-поваров (англ. язык) - страница 80

Молекулярная гастрономия для креативных шеф-поваров (англ. язык)

There are two possible arrangements of these three chains, giving a “collagen 1” and a “collagen

2”.

M = 30 000

L = 280 nm = 2.80.10-7m.

Diameter = from 1.4 10-9 m to 1.5.10-9 m

The gelatine is a gel made of water dispersed in a network of collagen, which is a solid

continuous phase. Between 60 and 65°C, the collagen splits up and the triple helix is then destroyed and

a big protein network is created. By cooling, the “simple” proteins are connected together and form a

protein network, which keeps a continuous structure.

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A protein is constituted by amino acid (AA). If we know the amino acid length, we can deduct the

length of a protein, in particular, the collagen. Indeed, an amino acid is connected with another one by a

peptidic link. By neglecting the influence of the radical, we can say that an amino acid has the length of a

carbon-carbon link, and of a peptidic link: both of a length of the order of 1,5 Angstrom.

H2N

CH

C

R

NH

O

CH

C

R

OH

O Figure 37 : Two amino acids connected by a peptidic link

The length of an AA, on a polypeptidique chain is thus of the order of 5 angstroms, is l = 5.10-10m.

By estimate, we can assimilate an essential molecule of collagen to a chain constituted of N = L/l amino

acids.

Proteins can have various sizes due to the properties of the radicals of each amino acid. We shall

thus estimate the two extreme shapes that a polypeptidic chain can take; ...

acids.

Proteins can have various sizes due to the properties of the radicals of each amino acid. We shall

thus estimate the two extreme shapes that a polypeptidic chain can take; namely a thread for the most

developed shape and a cube of linked amino acids for the most compact shape.

If we take this molecule of its most compact shape, it would have a shape of cube of edge equal

to n. One of the faces of this cube would cover the surface of our air bubble.

Smin = ((n (1/3))*l) 2

Smin =

L

l

.c

e

o

.

o

(2/3)

l 2

Also, the most free shape would form a network of fibres of collagens, like a square of L. of

surface:

Smax = 1

2

L 2

The number of molecules of collagen necessary to create a foam bubble is thus:

n(c1b) = Sb

S

Let Nc be the number of bubbles which can be made using all the molecules of collagen of the

solution:

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