title: Isolation and structural characterization of new anthocyanin-derived yellow pigments in aged red wines.
abstract: Two newly formed yellow pigments that revealed unique spectral features were detected and isolated from an aged Port red wine by TSK Toyopearl HW-40(s) gel chromatography and characterized by UV-visible spectrophotometry, 1H NMR and 13C NMR, and mass spectrometry (LC-ESI/MS). The UV-vis spectra of these pigments showed maximum absorption at 478 nm that is significantly hypsochromically shifted from those of original grape anthocyanins and other pyranoanthocyanins, exhibiting a more yellow hue in acidic solution. The structures of these pigments correspond to methyl-linked pyranomalvidin 3-glucoside and its respective coumaroyl glucoside derivative. They were shown to arise from the reaction between acetoacetic acid and genuine grape anthocyanins. Isolation and NMR identification using 1D and 2D NMR techniques are reported for the first time for this new family of anthocyanin-derived yellow pigments occurring in red wines.
authors.affiliation: Centro de Investigaçâo em Química, Departamento de Química, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal.
authors.forename: Jingren
authors.initials: J
authors.lastname: He
authors.forename: Celestino
authors.initials: C
authors.lastname: Santos-Buelga
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.forename: Nuno
authors.initials: N
authors.lastname: Mateus
authors.forename: Victor
authors.initials: V
authors.lastname: de Freitas
mesh_terms: D000872:Anthocyanins / Q000737:chemistry* / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D021241:Spectrometry, Mass, Electrospray Ionization; D013053:Spectrophotometry; D013997:Time Factors; D014920:Wine / Q000032:analysis*
chemical_list: D000872:Anthocyanins