title: Strecker type degradation of phenylalanine by 4-hydroxy-2-nonenal in model systems.
abstract: The reaction of 4-hydroxy-2-nonenal, an oxidative stress product, with phenylalanine in acetonitrile-water (2:1, 1:1, and 1:2) at 37, 60, and 80 degrees C was investigated to determine whether 4-hydroxy-2-alkenals degrade amino acids, analogously to 4,5-epoxy-2-alkenals, and to compare the reactivities of both hydroxyalkenals and epoxyalkenals for production of Strecker aldehydes. In addition to the formation of N-substituted 2-pentylpyrrole and 2-pentylfuran, the studied hydroxyalkenal also degraded phenylalanine to phenylacetaldehyde with a reaction yield of 17%. The reaction mechanism is suggested to be produced through the corresponding imine, which is then decarboxylated and hydrolyzed. This reaction also produced a conjugated amine, which both may be one of the origins of the produced 2-pentyl-1H-pyrrole and may contribute to the development of browning in these reactions. 4-Hydroxy-2-nonenal and 4,5-epoxy-2-decenal degraded phenylalanine in an analogous extent, which is likely a consequence of the similarity of the degradation mechanisms involved. These results suggest that different lipid oxidation products are able to degrade amino acids; therefore, the Strecker type degradation of amino acids produced by oxidized lipids may be quantitatively significant in foods.
authors.affiliation: Instituto de la Grasa, Consejo Superior de Investigaciones Científicas, Avenida Padre García Tejero 4, 41012 Seville, Spain.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Hidalgo
authors.forename: Emerenciana
authors.initials: E
authors.lastname: Gallardo
authors.forename: Rosario
authors.initials: R
authors.lastname: Zamora
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry; D002849:Chromatography, Gas; D007202:Indicators and Reagents; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015416:Maillard Reaction; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010649:Phenylalanine / Q000737:chemistry*
chemical_list: D000447:Aldehydes; D000588:Amines; D000596:Amino Acids; D007202:Indicators and Reagents; D008055:Lipids; D010649:Phenylalanine; C027576:4-hydroxy-2-nonenal