Relative Reactivities of Amino Acids in the Formation of Pyridines, Pyrroles, and Oxazoles

Effect of amino acids on the composition and properties of extruded mixtures of wheat flour and glucose

“…In dry systems (as in our experiments), the a-amino group is more reactive than the eamino group [21], therefore, the methylene chain of lysine does not much influence the composition of pyrazines. High pyrazine contents were reported in model systems, where the reaction temperature was higher than in our extrusion experiments [22], and the concentrations of reactants were also higher. In model systems, 2-methyl and 2,5-dimethyl pyrazines were most abundant in heated glucose-lysine mixtures [23], but in our extrusion experiments, methyl and trimethyl derivatives prevailed.…”

Comparison of the Maillard-Derived Aroma Volatiles of Cooked Milled and Brown Rice

“…2-Acetyl-1-pyrroline (2AP) was only found in the cooked milled fragrant rice; it may already be present in the raw fragrant rice. The reaction of amino acids with reducing sugars may contribute to formation of pyrazine, pyridine, pyrrole, and oxazole [7,8]. Cao et al [5] found this phenomenon in ageing of milled rice, and Lamberts et al [6] in parboiling of brown rice.…”

Reductive Amination of 1-Hydroxy-2-propanone Over Nickel and Copper Catalysts

“…In the Maillard reaction, α-amino carbonyls are considered precursors of not only pyrazines and/or piperazines but also of other unsaturated heterocyclic compounds, such as oxazolines [17][18][19]30,50 , oxazoles 29,30,50,51 , imidazoles [28][29][30][31]50 , imidazolines 50,52 , or pyrroles 29,30,51,53 (see Scheme 6). Nevertheless, under the reaction conditions of the reductive amination, oxazolines are unstable and react with the amination agent and hydrogen to form two molecules of corresponding α-amino alcohols 10 .…”