title: Two novel pyrrolooxazole pigments formed by the Maillard reaction between glucose and threonine or serine.
abstract: Pyrrolothiazolate formed by the Maillard reaction between l-cysteine and d-glucose has a pyrrolothiazole skeleton as a chromophore. We searched for a Maillard pigment having a pyrrolooxazole skeleton formed from l-threonine or l-serine instead of l-cysteine in the presence of d-glucose. As a result, two novel yellow pigments, named pyrrolooxazolates A and B, were isolated from model solutions of the Maillard reaction containing l-threonine and d-glucose, and l-serine and d-glucose, respectively, and identified as (2R,3S,7aS)-2,3,7,7a-tetrahydro-6-hydroxy-2,5,7a-trimethyl-7-oxo-pyrrolo[2,1-b]oxazole-3-calboxylic acid and (3S,7aS)-2,3,7,7a-tetrahydro-6-hydroxy-5,7a-dimethyl-7-oxo-pyrrolo[2,1-b]oxazole-3-calboxylic acid by instrumental analyses. These compounds were pyrrolooxazole derivatives carrying a carboxy group, and showed the absorption maxima at 300-360 nm under acidic and neutral conditions and at 320-390 nm under alkaline conditions.
authors.affiliation: a Department of Nutrition and Food Science , Ochanomizu University , Tokyo , Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Noda
authors.affiliation: a Department of Nutrition and Food Science , Ochanomizu University , Tokyo , Japan.
authors.forename: Masatsune
authors.initials: M
authors.lastname: Murata
mesh_terms: D005947:Glucose / Q000737:chemistry*; D015416:Maillard Reaction; D010080:Oxazoles / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D010860:Pigments, Biological / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D012694:Serine / Q000737:chemistry*; D013912:Threonine / Q000737:chemistry*
chemical_list: D010080:Oxazoles; D010860:Pigments, Biological; D013912:Threonine; D012694:Serine; D005947:Glucose
keywords: Maillard reaction; browning; pyrrolooxazole; threonine; yellow