Kinetics and thermal degradation of the fructose-methionine Amadori intermediates. GC-MS/SPECMA data bank identification of volatile aroma compounds

Abstract Fructose-methionine Amadori intermediates, prepared from d -glucose and l -methionine, were purified by semi-preparative HPLC. Structural elucidation was achieved by 13 C-NMR and mass spectrometry in the FAB + and FAB − modes. Constant rates of formation of glucosylamine and the Amadori intermediate, and their thermal degradation into reductones and methionine as well as into diglucosylamine, were observed. Thermal degradation of the Amadori intermediate gives not only the well-known degradation products of the sugar moiety and methional (from the Strecker degradation of methionine), but also several heterocyclic compounds (pyridines, pyrazines, pyrroles, and furans). Some of them contain a methylthiopropyl group in their side chain. These new compounds were identified by the fragmentation rules and the Kovats index additive properties. Out of the 80 compounds isolated, ∼ 70 were identified.