Glucose with glycine

Hayes (1960) observed that products from heating glucose with glycine in aqueous media under reflux conditions had some compositional properties and reactivities similar to those of the HAs isolated in aqueous base from a sapric histosol. The techniques used for the comparisons included differential thermal analysis (DTA) (see Figure 1.2). However, that work was done before the introduction of NMR to such studies. 

Figure 1.2. Differential thermal analysis for the humic acid fraction isolated in NaOH from a sapric histosol (1), from the acid precipitate isolated from products of the reaction of meth-ylglyoxal with glycine (2), and from the acid precipitate formed from the reaction of glucose with glycine (3), alkali lignin (4), casein (5), lignin-casein 3 1 complex (6), and lignin-casein 6 1 complex (7).

Haugaard, Tumerman, and Silvestri108 also investigated the reaction of D-glucose with glycine in aqueous solution at reflux temperature and measured, at intervals, the absorption (at 490 m/i) of the reaction mixture. The... 

Oh, Y.C. Shu, C.K. Ho, C.-T. Some volatile compounds from thermal interaction of glucose with glycine, diglycine, triglycine and tetraglycine. J. Agric. Food Chem. 1991, 39, 1553—1554. 

The reaction was named after the French chemist Louis Camille Maillard, who first described the formation of brown pigments formed during heating of glucose with glycine. The Maillard reaction has always attracted, and still attracts, the attention of many chemists. It has been studied for a century by food chemists, nutritionists, physiologists and physicians, but it is still impossible to present a complete reaction scheme due to its complexity. 

Pyraiines Formed from the Reaction of D-Glucose(Glc) with Glycine(Giy) at 300° and pH 4.5... 

Recovery experiments were conducted with the following standards, which were used as received without further purification 5-chlorouracil (Calbiochem), furfural (Aldrich), crotonaldehyde (Aldrich), caffeine (Aldrich), isophorone (Aldrich), 2,4-dichlorophenol (Aldrich), anthraquinone (Aldrich), biphenyl (Ultra Scientific), 2,4 -dichlorobiphenyl (Ultra Scientific), 2,6-bis(l,l-dimethylethyl)-4-methylphenol (Aldrich), 2,2, 5,5 -tetrachlorobiphenyl (Ultra Scientific), benzo[e]pyrene (Aldrich), bis(2-ethylhexyl) phthalate (Scientific Polymer Products), 4-methyl-2-pentanone (Aldrich), quinoline (Kodak), 1-chloro-dodecane (Eastman), stearic acid (Kodak), quinaldic acid (Aldrich), trimesic acid (Aldrich), glucose (Aldrich), glycine (Aldrich), and chloroform (Burdick and Jackson). 

The brown product or melanoidin which results from the Maillard reaction has been isolated from the products from various mixtures of reactants by numerous workers. A selection of these is given below. Maillard72, studied the interaction of D-glucose and other reducing sugars with glycine and several other amino acids at 34°, 40°, 100°, and 150°. 

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