Computational study on maillard reactions in foods

Abstract

By considering the formation of pyrazines (Pzs) as one of the most possible final products, Density Functional Theory (DFT) calculations have been performed at the standard state on four designated mechanisms of glyceraldehyde (Gald) and glycine (Gly) Maillard reaction involving unionised or unprotonated glycine (UGly), protonated glycine (PGly), deprotonated glycine (DGly) and glycine zwitterion (GlyZ) in the gaseous and aqueous states. i??GA? and i??EA? of different steps have been calculated by following the total mass balance. Thus, possibility of formation of different intermediates, and different steps to take place, has been evaluated. The result reveals that Gald+UGly reaction favours the formation of Pzs mainly in the gaseous phase, whereas Gald+DGly reaction favours in both gaseous and aqueous phases. Gald+PGly and Gald+GlyZ reactions have been found to be less favourable for the formation of Pzs. Amadori Rearrangement Products (ARPs) are the final products in the initial stage of the reaction. Gald+DGly reaction favours the formation of the enol and keto forms of ARPs, and Gald+UGly reaction favours the formation of the keto form of ARPs. Methyl glyoxal (MG) has been found to be the most likely intermediate in the reaction. Both 1- and 3-deoxyosone routes in the intermediate stage are able to produce MG as the final product. In the final stage of the reaction, aminoacetones (Aaces) have been found to be the most likely precursors for the formation of pyrazine rings, and oxidation plays an important role. In the early stage of the reaction, formation of hydroxyacetaldehyde (Hald) from Gald has been found to be favoured in the aqueous phase reaction. The global minimum (GM) and local minima (L1 a?? L3) have been located on the potential energy surface (PES) of Hald.