Glucose-glycine reaction

The glucose-glycine reaction has therefore been reinvestigated using glucose labelled with 90 % at C-1. The behavior of a few potential intermediates under similar reaction conditions has also been studied. 

There are some reports on possible mechanisms behind these effects of severe heat treatment. Adrian (1) has shown that water-soluble premelanoidins from a glucose-glycine reaction mixture reduce the protein digestibility and affect the utilization of... 

Kato, H., Yamamoto, M., and Fujimaki, M. Mechanisms of browning degradation of D-fructose in special comparison with D-glucose-glycine reaction, Agric. Biol. Chem., 33, 939, 1969. 

The formation of brown pigments via the Maillard reaction, especially in model systems (e.g. glucose-glycine), usually follows zero-order kinetics, but the loss of reactants has been found to follow first- or second-order kinetics in foods and model systems. Activation energies of 109, 116 and 139 kJ mol-1 have been reported for the degradation of lysine, the formation of brown pigments and the production of hydroxymethylfurfural (HMF), respectively. 

Glucose, glycine, phosphate (NaH2PC>4.1 aq) and water were mixed in the amounts listed in Table I. The pH of the reaction mixture was adjusted at pH-5.6. The reactions were performed as mentioned above. 

Superoxide radicals are another factor in oxidative damage. They can be determined with nitrobluetetrazolium (NBT), which then forms the colourless formazan. When melanoidins scavenge the superoxide radicals, the colour of the NBT persists.490,491 The activity of a glucose-glycine melanoidin on superoxide radicals is equivalent to the effect of 16 units of superoxide dismutase. The effect of the HMM and LMM fractions of this melanoidin is almost the same. The reaction rate constant of the melanoidin was markedly higher than that of ascorbic acid. If this were due to the reductone structures embedded in the melanodin, it is difficult to explain why the reducing power of the melanoidins is only 0.7 that of ascorbic acid.490... 

Y. Yoshimura, T. Iijima, T. Watanabe, and H. Nakazawa, Antioxidative effect of Maillard reaction products using glucose-glycine model system, J. Agric. Food Chem., 1997, 45, 4106 1109. 

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