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The Maillard Reaction. Chemistry Biochemistry and Implications

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The Maillard Reaction
Chemistry, Biochemistry and
Implications. By
Harry Nursten.
Royal Society of
Chemistry, Cambridge 2005.
206 pp., hardcover,
£ 84.95.—ISBN
Even today, the Maillard reaction still
ranks among the most fascinating of
chemical reactions. It has long been of
concern to food chemists especially, as it
can have a decisive influence on food
quality. The reaction takes its name
from the French physician and chemist
Louis-Camille Maillard, who, in 1912,
was the first to describe products that
arise from the reaction of reduced
sugars with amino acids. The overall
reaction can be described by seven
individual reaction schemes, which can
produce hundreds of different compounds.
The initial reactions are: firstly, the
condensation of carbonyl compounds
(usually reduced sugars) with amino
compounds (usually amino acids, peptides, or proteins), and secondly the
Amadori rearrangement. This yields
colorless products that do not absorb
light, even in the UV region. That is
followed by the dehydrogenation and/or
fragmentation of the sugars, and by the
breakdown of amino acids by the
Angew. Chem. Int. Ed. 2005, 44, 7503 – 7504
Strecker reaction, leading to colorless
or yellow products, which show a strong
absorption in the UV region. Finally,
aldol condensation reactions and aldehyde–amine condensation reactions (in
this case heterocyclic nitrogen compounds) lead to polymers with an
intense brown color. Since carbonyl
and amino compounds occur almost
everywhere, Maillard products are
found not only in foodstuffs but also in
all living cells, in soil, in textiles, and
even in some pharmaceutical products.
In view of the thousands of existing
publications about the Maillard reaction, one might think that everything to
be said about this reaction had already
been said, but that impression is very
much mistaken, as Harry Nursten makes
clear in his excellent monograph. A
scientist seeking an overview of all the
most recent results from research on the
Maillard reaction can read the proceedings of the conferences devoted to the
subject, which have been held at intervals of about four years. However, as
always with conference reports, the
difficulty is to separate the important
from the unimportant. The author of
this monograph is a well-known specialist on the Maillard reaction, who has
been studying all facets of the subject for
nearly 60 years, and therefore he has a
more thorough knowledge about the
reaction than scarcely any other
researcher. In this book, he not only
describes all the important results on the
Maillard reaction that have been published up to now, but also evaluates
them. His evaluation of the results about
this complex reaction, which affects
almost every aspect of modern life, is
especially important, because otherwise
one could easily lose sight of the bigger
picture and overlook key aspects. An
important point is that the author not
only covers the literature up to 2004 but
also discusses earlier groundbreaking
studies. Thus, he has succeeded
extremely well in summarizing current
knowledge about the Maillard reaction.
Sometimes, the descriptions in the
individual chapters are so thorough that
it seems as if one were reading the
original publication. Although readers
will appreciate the author6s careful
attention to detail, this sometimes
makes it difficult to recognize the connections and form a balanced picture.
However, perhaps this amount of detail
is really necessary for describing such
complex reactions, which are important
in fields that range from organic chemistry, through food chemistry, to physiological chemistry.
The monograph has a clear and
straightforward structure. After a short
historical introduction, the second chapter describes the separate chemical
reactions that are the basic components
of the complex Maillard reaction. Here,
Nursten not only explains the reaction
mechanisms but also discusses the reaction conditions in considerable detail in
some cases. Presenting the subject in this
way enables the reader to understand
that even minor changes in the reaction
conditions or in the substrates can lead
to completely different products.
The next chapter discusses some
factors that have important effects on
the course of the Maillard reaction, such
as new technologies in the food industry,
which use high pressures or other conditions. This is followed by chapters on
non-enzymatic browning reactions, and
on the formation of aroma substances or
off-flavor compounds. Other important
aspects discussed are the various interactions of Maillard reaction products
with the organism. These raise important questions concerning the toxicity
and bioavailability of such products for
humans. In particular, there have been
many publications in the past few years
that report studies of the effects of
Maillard reaction products in causing
negative physiological reactions and
influencing aging processes; some
results in this fascinating area of
research are discussed at length. It is
now widely recognized that advanced
glycation end-products (AGEs) are produced by some reactions.
Other chapters deal with the effects
of the Maillard reaction in altering the
technological properties of food products, and with methods for preventing
undesirable non-enzymatic browning
reactions in foods. The book ends with
a chapter on ways of inhibiting in vivo
Maillard reactions, a topic that is attracting increasing attention in the area of
health research.
Professor Nursten6s monograph is
essential reading for all scientists who
are concerned with the effects of the
Maillard reaction, which are important
) 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
in nearly every aspect of human life.
Although the attention to detail that was
mentioned above makes some parts of
the book rather heavy going, I strongly
recommend it to chemists, food chem-
ists, biochemists, physiologists, nutrition
scientists, and pharmacologists.
Universit5t Hamburg (Germany)
Hans Steinhart
Institut f2r Biochemie und
DOI: 10.1002/anie.200585332
) 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2005, 44, 7503 – 7504
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chemistry, implications, reaction, maillard, biochemistry
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