title: Identification of the blue pigment formed in a D-glucose-glycine reaction system.
abstract: D-Glucose (0.7 M), glycine (0.3 M), and sodium hydrogencarbonate (0.1 M) were dissolved in aqueous 30% ethanol at pH 8.0 and left at 50 °C for 4 d in a dark room under nitrogen displacement. The resulting blue pigment was isolated and purified from the blue solution by anionic exchange and gel filtration chromatography. This blue pigment, which is designated Blue-G1, was identified as 5-[1,4-bis-carboxymethyl-5-(2,3,4-trihydroxybutyl)-1,4-dihydropyrrolo[3,2-b]pyrrol-2-ylmethylene]-1,4-bis-carboxymethyl-2-(2,3,4-trihydroxybutyl)-4,5-dihydropyrrolo[3,2-b]pyrrol-1-ium. Blue-G1 had two symmetrical pyrrolopyrrole structures with a trihydroxybutyl group. Blue-G1 had a polymerizing activity, suggesting it to be an important Maillard reaction intermediate through the formation of melanoidins.
authors.affiliation: Department of Agricultural Chemistry, Faculty of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan.
authors.forename: Yoriyuki
authors.initials: Y
authors.lastname: Ono
authors.forename: Hirohito
authors.initials: H
authors.lastname: Watanabe
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Hayase
mesh_terms: D005947:Glucose / Q000737:chemistry* / Q000378:metabolism*; D005998:Glycine / Q000737:chemistry* / Q000378:metabolism*; D010860:Pigments, Biological / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism*; D017693:Sodium Bicarbonate / Q000737:chemistry
chemical_list: D010860:Pigments, Biological; D017693:Sodium Bicarbonate; D005947:Glucose; D005998:Glycine