Identification of new heterocyclic nitrogen compounds from glucose-lysine and xylose-lysine maillard model systems.
Aqueous sugar (glucose or xylose)-lysine model systems were heated at 80 degrees C for 6 h with the pH maintained at a predetermined value (3, 4, or 5). Selected compounds were isolated by combinations of solvent extraction and semipreparative HPLC, prior to identification by NMR and mass spectrometry. Two compounds were identified from the pH 5 glucose system and were identified as epsilon-[2-formyl-5-(hydroxymethyl)pyrrole-1-yl]-L-norleucine (pyrraline) and the new compound, 1-(5-carboxy-5-aminopentyl)-2-formyl-3-(1,2,3-trihydroxypropyl)pyrrole. A third compound was partially characterized. 2-Acetyl-5-hydroxymethyl-5,6-dihydro-4H-pyridinone was identified in the pH 3 xylose system, and the new compound, 8-furan-2-yl-methyl-5-hydroxymethyl-5,6-dihydro-indolizine-1,7-dione, was identified in the pH 4 xylose system. 2-Furfurylidene-4-hydroxy-5-methyl-3(2H)-furanone was identified in both xylose systems. Mechanisms of formation are proposed for the novel compounds.
Bailey
R G
RG
School of Food Biosciences, The University of Reading, Whiteknights, Reading, RG6 6AP, UK.
Ames
J M
JM
Mann
J
J
D002851:Chromatography, High Pressure Liquid; D005947:Glucose / Q000032:analysis; D006571:Heterocyclic Compounds / Q000032:analysis* / Q000302:isolation & purification*; D008239:Lysine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015416:Maillard Reaction; D013058:Mass Spectrometry; D008956:Models, Chemical; D014994:Xylose / Q000032:analysis
D006571:Heterocyclic Compounds; D014994:Xylose; D005947:Glucose; D008239:Lysine