Generation and the fate of C2, C3, and C4 reactive fragments formed in Maillard model systems of [13C]glucose and [13C]glycine or proline.

Model studies with pyrolysis/GC/MS using labeled [13C] glucoses with labeled [15N/13C]glycines and proline have indicated that the Maillard model systems consisting of glucose and glycine or proline generate similar C2, C3, C4 fragments such as acetic acid, and pyruvaldehyde. Furthermore, the labeling studies have enabled the identification of the origin of these reactive intermediates and their stable end-products such as N-acetylpyrrolidine, 1-(1'-pyrrolidinyl)-2-propanone amd 1-(1'-pyrrolidinyl)-2-butanone in proline model system and pyrazines and pyrazinones in glycine. In glycine model system, pyruvaldehyde and 2,3-butandione were found to be formed either from the degradation of the carbohydrate moiety (90 and 35%, respectively) or by an aldol-type interaction of glycine with alpha-ketoaldehydes. The same intermediates in proline system are formed exclusively from the carbohydrate degradation pathway.