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The reaction of Maillard is, today, known as being a complex whole of reactions putting in?uvre, in biological or agroalimentary substrates, compounds presenting of the reducing groupings (aldehydic or ketonic), and of the amino compounds which react between them to produce aromatic and coloured substances. The compounds with grouping carbonyl (C=O) can be carbohydrates (sugars) or products of oxidation of the lipids. The function amine can come from amino acids themselves, proteins or natural or exogenic amines. This reaction is also called " not-enzymatic tanning ". The principal stages of the successive or simultaneous reactions which occur were described for the first time by J.E.Hodge (Chemistry of Browning reactions in model systems. J Agric. Food Chem. , 1953, 1, 928-943). The first stage includes/understands the condensation of an amino acid with a reducing sugar ; to form products of rearrangement of Amadori or Heyns. The second stage gathers at least 4 ways of degradation of the products resulting from these rearrangements. They depend on the substrate and constitute, themselves a complex whole of dehydrations, eliminations, cyclizations, fragmentations... leading to a pool of intermediate molecules and compounds of flavor. The third stage corresponds to the formation of the often named pigments " mélanoïdines " and which are, on the chemical level, of the unsaturated acids polycarboxylic. The production of the aromatic molecules appears in the reactional sequences and corresponds to chemical species such as the hydroxyméthylfurfural, the dihydropyranones, the furanones, pyruvaldehyde or the diméthylpyrazine. Among the parameters which influence the amplitude or the speed of the reactions, one can quote : -
the nature of sugars, It is also known, whether the sulphur dioxide, free or in the form of sulphites, delays or even inhibits the formation of pigments. Its use, however, is limited by the regulation. In food, these reactions are required (and controlled) with an aim of improving sensory qualities of certain food (roast meat, fried potatoes, crust of the bread, torrefied coffee...). In certain cases, it is considered that the effects are unfavourable (tanning at the time of the marked heating of milk or syrups and fruit juices, or at the time of the drying of the drieds milk, the meat or fish meals). One can note that these reactions, accelerated by heat, are associated the heat treatments of the food (pasteurization, sterilization, drying, cooking...) In the field of the nutrition, it was shown that certain products of the reaction of Maillard in food could have an antioxydant activity, but that others could have a certain toxicity. It was as proven as the reaction involved the destruction of the vitamin C and a nutritive loss in value of food, because of the loss out of sugars and essential amino acids. One also highlighted effects of certain products of the reaction on the metabolism of the minerals (zinc, in particular). Lastly, of the molecules such as heterocyclic amines, isolated from meat or roasted fish, under experimental conditions, showed mutagen and carcinogenic properties. Very current work examines the risks of development of cancers at the Man, knowing that, to the opposite, the appearance of antioxydant substances contributes to their reduction. In-vivo, i.e., in the cells and the organization, the reaction of Maillard seems speaker in the processes of slow degradation of molecules such as the collagen which enters the constitution of fabrics of the arteries, tend, skin,cristallin... At the time of the ageing of the organization, of the cells such as, neurons, hépatocytes, myocytes, fibroplastes, lymphocytes, would accumulate products of the reaction of Maillard That would be more important at the people suffering from diabetes and would intervene in the development of the cataracts. For V.M. Monnier and J.Baynes(1989, Toward has Maillard reaction Theory of Aging. In : Maillard Reaction in Aging. Liss Press Publ. New York), the reaction of Maillard is with the c?ur theory of ageing Lastly, the reaction of Maillard also intervenes in the processes of transformation of the vegetable matters in the grounds and contributes to the formation of the humus To finish this short presentation of current knowledge, here some works whose reading can be recommended to the specialists : - The Maillard Reaction in Food Processing, Human Nutrition and Physiology. P.A. Finot and coll, ED. Birkhäuser Verlag, Basel-Boston-Berlin, 1990 ISBN 3-7643-2354X - The Maillard Reaction in Foods and Medicine.J.O' Brien and coll, Royal Chem. Ploughshare., Cambridge.1998. ISBN 0-85404-733-6. - Maillard reactions in Chemistry, Food and Health. T.P. Labuza and coll, Royal Ploughshare. Chem., Cambridge.1994.ISBN 0-85186-802-9. One can as announce as the reaction of Maillard continues to give place to many research tasks in the world the number of annual publications, in specialized scientific reviews, or international conferences, rises to several hundreds.
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The reaction of Maillard applies in many different fields but mainly in:
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