| Pyrolysis/GC/MS was utilized as an integrated reaction, separation and identification system to study the thermal degradation products of non-volatile Maillard flavor precursors. Model systems of scL-phenylalanine (aromatic amino acid), glycine and scL-alanine (aliphatic amino acids), scL-serine (;Phenylalanine Amadori product and different model systems containing phenylalanine and different reducing sugars were studied. Ribbon pyrolysis was used to study the effect of temperature (150, 200, 250;Model studies using scD- (;A major product of the reaction of scD-glucose with excess glycine was detected by Py/GC/MS analysis and subsequently synthesized and isolated using focused microwave irradiation at atmospheric pressure conditions. Spectroscopic analysis by NMR, FTIR, MS and UV in conjunction with labeling studies have indicated the unknown compound to be 5-hydroxy-1,3-dimethyl-2 (1H) -quinoxalinone. The labeling studies indicated the incorporation of ten carbon atoms (six from sugar, one C-1 atom of glycine, and three C-2 atoms of glycine) and two nitrogens.;scL-Serine was found to be a unique amino acid generating in the absence of sugar a variety of heterocyclic compounds. Under pyrolytic conditions scL-serine can be viewed as a potential mixture of glycine, alanine, serine, formaldehyde and dicarbonyl compounds.;Model studies with scL-methionine provided evidence that methional (Strecker aldehyde) generated under Quartz tube pyrolysis undergoes secondary reactions with amino compounds generating 1,3-thiazines or 3-substituted pyridine in a similar fashion to that of scL-phenylalanine systems where 3-substituted pyridines were also identified. (Abstract shortened by UMI.). |
