| The ability of Pyrolysis-GC/MS analytical system---developed earlier to study the mechanism of Maillard reaction---was further enhanced to include chemical ionization, tandem mass spectrometry and a sample pre-concentration trap essential to detect minor components. Furthermore, the sample delivery during Py-GC/MS analysis was optimized and its relevance to the study of aqueous Maillard model systems was also characterized. The results of these investigations have indicated that the use of higher values of carrier gas flow rates or high constant pressures, during Py-GC/MS analysis can increase the total number of peaks and total area counts of the pyrograms. The influence of the reaction phase on the mechanism of formation of Maillard products was studied by comparison of 13C-label incorporation patterns of the common products formed in model systems consisting of labeled glycine and D-glucoses subjected to both pyrolysis and heating in aqueous solutions. Although pyrolysis reaction produced higher number of products, however, the major pathways of formation of variety of important Maillard products followed the same mechanism under both pyrolytic and aqueous systems. Furthermore, the advantages of the optimized system, were demonstrated both in the investigation of the mechanism of Maillard reaction, using L-serine and L-threonine as model systems and in the study of formation of Maillard generated carcinogens and chemical markers. Analyses of the pyrolysis products of [13C-1], [13C-2] and [13C-3] labeled L-serines and L-threonines have indicated the presence of three initial degradation pathways. Decarboxylation followed by deamination; a retro-aldol reaction and dehydration followed by isomerization, deamination and hydrolysis leading to the formation of pyruvic and 2-ketobutanoic acids. Interestingly, the amino carbonyl interaction between the resulting pyruvic acid and the aminoethanol can lead to the formation of an Amadori product identical in structure to that formed from alanine and glycolaldehyde, indicating the existence of another route to this important Maillard intermediate. This route was further confirmed through Py-GC/MS analysis using variously [13C]-labeled reactants and by FTIR spectroscopy. In addition, the ability of the optimized Py-GC/MS system to investigate the detailed mechanism of formation of Maillard generated carcinogens such as acrylamide and utilization of Maillard generated products such as 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-one as chemical markers for prediction of process lethality, were also demonstrated. |
