Carbohydrate and Amino Acid Degradation Pathways in l-Methionine/d-[¹³C] Glucose Model Systems

Abstract

Maillard model systems consisting of labeled D-[(13)C]glucoses, L-[(15)N]methionine, and L-[methyl-(13)C]methionine, have been utilized to identify the amino acid and carbohydrate fragmentation pathways occurring in the model system through Py-GC/MS analysis. The label incorporation analyses have indicated that the carbohydrate moiety produces 1-deoxy- and 3-deoxyglucosones and undergoes C(2)/C(4) and C(3)/C(3) cleavages to produce glycolaldehyde, tetrose, and C(3)-reactive sugar derivatives such as acetol, glyceraldehyde, and pyruvaldehyde. Glycolaldehyde was found to incorporate C-1, C-2 (70%) and C-5, C-6 (30%) glucose carbon fragments, whereas the tetrose moiety incorporates only C-3, C-4, C-5, C-6 glucose carbon atoms. In addition, the major source of reactive C(3) fragments was found to contain C-4, C-5, C-6 sugar moiety. On the other hand, methionine alone also generated Strecker aldehyde as detected by its condensation product with 3-(methylthio)propylamine. Plausible mechanisms were proposed for the formation of the interaction products between sugar and amino acid degradation products on the basis of the label incorporation patterns.

Recent Advances in the Chemistry of Strecker Degradation and Amadori Rearrangement: Implications to Aroma and Color Formation

“…(Barrett, 1985) can cause oxidative decarboxylation of amino acids at ambient temperatures followed by hydrolysis of the resulting imine to give Strecker aldehyde (pathway A). Amino acids alone (Yaylayan & Keyhani, 2001a) or in the presence of ␣-hydroxy carbonyl compounds (Shu, 1998) can also undergo thermal deamination and produce Strecker aldehydes at temperatures above 200˚C in the absence of oxidizing agents. Yaylayan and Keyhani (2001a) detected the formation of the imine 5 formed between the Strecker aldehyde and the resulting amine from decarboxylation of the amino acid when pyrolyzed alone at 250˚C for 20 s. On the other hand, Shu (1998) detected the formation of tetramethylpyrazine and the Strecker aldehyde of amino acids heated at 200˚C for 7 min in the presence of 3-hydroxy-2-butanone and proposed a decarbonylation mechanism followed by deamination (pathway B in Fig.…”

Formation of the peptide-specific imidazolidin-4-one moiety in alanine containing Maillard reaction mixtures

“…2). However, at temperatures higher than 250°C, alanine alone can undergo oxidative decarboxylation (Yaylayan, 2003;Yaylayan & Keyhani, 2001) to form the imine shown in Fig. 5 the latter can hydrolyse into acetaldehyde thus providing the essential component for the formation of 3-ethyl-2,5-dimethylimidazolidin-4-ones.…”

Synthesis and Odor Evaluation of Stereoisomers of Imine Derivatives in Roasted Spotted Shrimp

“…On the other hand, amines were generated by decarboxylation of these amino acids. Condensation of these aldehydes and amines afford imine derivatives 1 ± 4 [6]. Therefore, we predict that the absolute configuration of all these natural imines must Table 2.…”