Computational studies on glyceraldehyde and glycine Maillard reaction-II

Abstract

Density functional theory calculations have been performed on the proposed mechanism for the intermediate stage of glyceraldehyde and glycine Maillard reaction under different pH conditions at the standard state. By following the total mass balance, possibility of the formation of different compounds in the proposed mechanism has been tested by estimating the Gibb's free energy changes of the reaction. Electronic energy changes have also been calculated to observe the internal energy changes during the reaction. The result reveals that methyl glyoxal is one of the most likely product in the intermediate stage of the reaction. 3-Deoxyosone route in the intermediate stage is feasible for the production of methyl glyoxal in glyceraldehyde+unprotonated glycine reaction, whereas both of the 3- and 1-deoxyosone routes are feasible in glyceraldehyde+deprotonated glycine reaction. As both of the 3- and 1-deoxyosone routes favor the production of methyl glyoxal, glyceraldehyde+deprotonated glycine reaction is assumed to be more feasible for the nonenzymatic browning than that of the others. Glyceraldehyde+protonated glycine and glyceraldehyde+glycine zwitterion reactions are assumed less favorable for the production of methyl glyoxal. These findings will be helpful for further studies, and finding out proper mechanisms of the reaction.