Maillard reaction carbohydrate intermediates

J. Hirsch, V. V. Mossine, and M. S. Feather, Detection of some dicarbonyl intermediates arising from the degradation of Amadori compounds (the Maillard reaction), Carbohydr. Res., 1995, 273, 171-177. 

Many desirable meat flavor volatiles are synthesized by heating water-soluble precursors such as amino acids and carbohydrates. These latter constituents interact to form intermediates which are converted to meat flavor compounds by oxidation, decarboxylation, condensation and cyclization. 0-, N-, and S-heterocyclics including furans, furanones, pyrazines, thiophenes, thiazoles, thiazolines and cyclic polysulfides contribute significantly to the overall desirable aroma impression of meat. The Maillard reaction, including formation of Strecker aldehydes, hydrogen sulfide and ammonia, is important in the mechanism of formation of these compounds. 

The chemical degradation of carbohydrates, particularly under acidic conditions, produces reductones, furan derivatives, pyruvaldehyde, and so on, which can condense, either among themselves or with amino compounds (Maillard reactions), to produce dark-colored, amorphous products, similar to humic substances. Pyruvaldehyde, which has been held to be an intermediate in Maillard reactions, has been identified in many soils. Such con-... 

Interest in the structure and reactivity of D-fiuctosamine and its derivatives is determined by their practical significance for the food industry and for control/ treatment of diabetes-related pathologies, but also by a notable structural flexibility of this carbohydrate derivative, which may provide for some models that are unique for the field of carbohydrate chemistry. As an important and a major class of intermediates in the Maillard reaction, the fiuctosamine structure serves as a precursor of a broad variety of both low- and high-molecular-weight Maillard reaction products, hundreds of which have so far been identified. Here we consider only the most immediate transformation steps of D-fiuctosamine, while some of the more important Maillard reaction products whose origin can be traced to the D-fructosamine intermediates will be considered in Section IV. 

Dehydration of the carbohydrate portion in fiuctosamines probably proceeds through a series of enolic intermediates (Scheme 31), whieh eventually tautomerize into a-dicarbonyl stractures such as 60, 62, and 63, or cycUze into 2-furoylmethyl-amines (61) and many other heterocyclic derivatives. One of the major products of D-fructosamine degradation that occurs through the 1,2-enoUzation pathway is 3-deoxy-D-e 7 /jro-hexos-2-ulose (60), which is regarded as one of the most important intermediates in the Maillard reaction both in foods and in vivo ... 

Two new gymnemic acid congeners (1) have been isolated from the leaves of Gymnema sylvestre. A review of the Maillard reaction - in which oxidised derivatives of carbohydrates are proposed as important intermediates - has been published. Carbohydrate alcohols with other hydroxyl groups appropriately protected as acetals, ethers or benzoates are oxidised by "active" RUO2 - NaI04 under phase-transfer conditions to ketones, aldehydes or to... 

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