Effects of reaction conditions on volatile products from Maillard reaction of glucose and glutamic acid

In order to investigate the influences of reaction conditions on the formation of volatile compounds from a model Maillard reaction of glucose and glutamic acid in aqueous solutions, the changes of pH and UV-visible absorbance at different reaction conditions were analyzed. Furthermore, the generated volatile compounds under different reactant ratios, reaction times and solvents were identified by GC/MS. The results indicated that: 1) The UV-visible absorbance A_{294 nm} and A_{420 nm} increased with the increases of glutamic acid content in the model system, propanediol in solvent and reaction time, while A_{294 nm}/A_{420 nm} decreased. 2) The total amount of volatile compounds, and the yields of pyridines, pyrazines, pyrroles, furans, furanones, organic acids and carbocyclic compounds increased, while the yields of pyranones, esters and aliphatic compounds increased at first and then decreased with the prolonged reaction time. When the content of glutamic acid increased in glucose/glutamic acid model system, the total amount of volatile compounds and the generation of pyridines, pyrroles, furans, furanones, esters, carbocyclic compounds and pyranones increased. The yields of volatile compounds increased with the increase of propanediol content in solvent, except for esters and aliphatic compounds.