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1er article published on the " reaction of Maillard "
report of the Academy of Science,
year 1912, n° 154, pages 66 to 68
Reports, November 27, 1911 ; C.R. Biol Ploughshare.
December 2, 1911.
MEETING OF JANUARY 8, 1912
Complete
text
CHEMISTRY Organics-Action of the amino acids on sugars; formation of the
mélanoïdines by methodical way.
Note
of Mr Louis Camille MAILLARD
presented by Mr Armand GAUTIER
My
research on the role of alcohols in the natural synthesis of albuminoids
led me to put the amino acids in the presence of an alcohol complexes
universally widespread in the alive beings, D-glucose. But here the role
of the aldehydic function prevails on that of the alcoholic functions, at
least when glucose is in excess.
If
in a tube one places 1 part of glycocolle with 4 parts of glucose and 3 to
4 parts of water, then that one carries to the bain-marie to facilitate
dissolution, the liquid takes a very recognizable yellow colour at the end
of ten minutes at the maximum. Colouring is accentuated with an increasing
speed, and arrives rather quickly at brown dark ; later one sees foaming
the liquid, by CO 2 release which one recognizes by leading gas
by means of a draught in baryta.
The
gas CO2 perhaps : or remains of the carboxyl of the glycocolle,
or the product of oxidation of other carbon atoms by borrowed oxygen,
either with the oxhydriles of glucose, or with the atmospheric air.
Into
a bell on mercury, one introduces 0,5 G of glycocolle, 2 G of glucose, 2
cm3 of water, and 14,6 cm3 of oxygen. After 6 hours
spent with 100°, one finds 12,6 cm3 of oxygen, that is to say a
disappearance of 2 cm3 only, whereas it was formed 22,9 cm3
of CO2. This gas thus does not borrow its oxygen from the
atmosphere.
With
a device where the gas products are led in absorbers, 0,4993 G of
glycocolle and 2,0044 G of glucose provided in 7 hours 0,1048 G of CO2.
Dried cold in the vacuum, the residue shows a loss of 0,6227 G, of which
0,5179 G are other thing that CO2. However, the centesimal
analysis of this residue reveals that this difference is water, whose
relationship with releasedCO 2 answers the expression (CO2+12H2O).
The CO 2 oxygen thus does not come from glucose.
The
outburst of carbon dioxide results from the scission of carboxyl
pertaining to the glycocolle. If it is admitted that this scission is
correlative fixing of nitrogen on the carbon aldehydic of sugar, we are
led to think that the molecules of glucose, at least two, which enter the
constitution of the new body, test dehydrations which create double
connections and perhaps cycles. The substances noirâtres thus formed could
be polycyclic molecules with 1 nitrogen atom.
I
generalized the reaction by treating glucose by the glycocolle, sarcosin,
alanine, valin, leucine, tyrosin, the glutamic acid. Alanine is most
active of amino acids, which is not to surprise when one knows his capital
role in biological Chemistry. With the glycocolle, the xylose and the
arabinose react instantaneously ; fructose, galactose, glucose and
mannose, rather quickly ; lactose and the maltose, slowly ; saccharose at
all during several hours, after which occurs a slow reaction, consecutive
undoubtedly with an unfolding.
Force with 150°, enough rapid with 100°, the reaction is observed after a
few days with 37°, and even below ; it is conceived besides that various
substances or various modes of energy could accelerate it.
The consequences of these facts appear as many to me as interesting in
various fields of Science : not only in physiology and pathology human,
but also in vegetable physiology (cyclic alkaloids, etc), in agronomy
(maturation of the manures, humus, various industries), in geology (mineral
fuels, etc). The only enumeration of these consequences, of which several
can be regarded as obvious, would be too long here.
I
will announce only one of them : the disturbance brought in all the
techniques of analysis or materials provide at the same time amino sugars
and acids : for example, in the hydrolyses the proteinic ones or fabrics,
one can find like amino acids only the fraction which has escaped with the
action of sugars. This is why these hydrolyses provide mélanoïdines, of
unknown constitution up to now, and whose composition even never could be
defined. I ensured myself that the products of the reaction that I
announce are precisely mélanoïdines ; but while old the mélanoïdines
provided by the chance was only inextricable mixtures deriving from varied
amino acids and can be various sugars, we are able today individually to
carry out the condensation of an amino acid defined with a definite sugar.
It is thus allowed to hope that the present method will bring explanations
comparable with those which substitution for the study provided, with the
inextricable mixtures which are natural peptones, of voluntarily built
polypeptides. One will be able consequently to study the constitution of
the mélanoïdines on which my tests project already some gleams.
The
range of the general reaction that I announce has of equal only its
extreme facility : one is surprised that it is not for a long time known
in its least details. I was there leads methodically by my research on the
part which complex alcohols in the sequence of the amino acids play.