Maillard reactions are a complex issue. They were first
discovered in 1912 by Maillard, who discovered 350 new chemical
species in grilled potatoes; but the terminology "Maillard reaction"
applies to chemical reactions between protids and sugars, not
necessarily producing a roast aroma. The reactions usually produce a
typical brown color, such as in bread's crust. There are early and
advanced reactions; some reactions require a high temperature, others
not; the amount of molecules produced depend on the temperature and
the processing time. Even cold storage can produce Maillard reactions.

These reactions have been extensively studied by scientists; tens of
articles are written each year. I still didn't find the time to read
any of them but here are a few excerpts from abstracts:

"In the 90 degree C test series the furosine values rose from 34
mg/litre (30 minutes) to 94 mg/litre (2h holding time) in the milk"
(Journal of the Science of Food and Agriculture 70(3): 307-310)

[NB: the author studies the formation of early Maillard products]

"When aqueous solutions of histidine and glucose were heated to 100,
120, 150 or 180 degree C or when this mixture was roasted at 220
degree C, a total of 231 volatile compounds were identified"
(J. of Agr. and Food Chemistry 43(8): 2226-2230)

"Each model system containing threonine, glucose, and creatine was
processed for 2h at a temperature between 125 and 250 degree
C. Neither MeIQ-x or DiMeIQ-x was found at processing temperatures
lower than 150 degree C. At temperatures between 150 and 200 degree C,
AIA concentrations increased with processing time. However, at 225 and 250
degree C the concentrations of the two products increased during the
15-30 min of processing and then decreased for the remainder of the
processing run. MeIQ-x and DiMeIQ-x did not appear in the reaction
mixture until almost all of the creatine was converted into
creatinine. This systematic study suggests that maintaining cooking
temperatures below 150 degree C may reduce the formation of MeIQ-x and
DiMeIQ-x in food."
(J of Agr. and Food chemistry 43(6): 1678-1684)

Comments:
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The non-biochemist reader of Burger's "Manger Vrai" may be confused by
arguments such as "There are 350 New Chemical Species in a grilled
potato; Maillard reactions occur at lower temperatures too". While
these facts are true, one must keep in mind that a boiled potato
certainly doesn't contain all these 350 types of molecules (boiled
potatoes do not have any roast aroma...), and mild cooking produces
much less "abnormal molecules". And since Maillard reactions occur at
low temperatures too (such as during cold storages), the same
reasoning as Burger's would lead to the conclusion that we shouldn't
eat at all... IMO, if cooked food had to be eaten, foods which are
brown or with a roast aroma should be avoided, but the body probably
has the ability to metabolize the few Maillard molecules that appear
in mildly cooked food.

Another question is: what happen to "abnormal" molecules? Do they
really accumulate in the body? Are they eliminated after several years
of raw diet? Burger thinks it is the case, otherwise we couldn't
detoxify.
Maybe it is a matter of concentration, the immune system could have
the ability to eliminate a small amount of xenobiotics. We shouldn't
forget that vegetables have invented more alkaloids, terpenes, sugars,
etc. than all chemists on earth, and that metabolization products of
bacteria are at least as numerous.

Best,

Jean-Louis