title: Unusual color change of vinylpyranoanthocyanin-phenolic pigments.
abstract: Anthocyanins are responsible for an interesting variety of colors in flowers, red fruits, and plant-derived foodstuffs. Experimental evidence is presented supporting an unusual color change from red to blue during storage. It has been investigated as a function of temperature at constant pH (pH <2). The color properties of the vinylpyranoanthocyanin pigments, usually designated portisins, have been studied in this work using both experimental and theoretical techniques. The visible spectra obtained from the two approaches were in good agreement. This behavior was explained by a reversible physical-chemical change due to electronic and vibrational properties.
authors.affiliation: REQUIMTE/Chemistry Department, University of Porto, Porto, Portugal.
authors.forename: Alexandre R F
authors.initials: AR
authors.lastname: Carvalho
authors.forename: Joana
authors.initials: J
authors.lastname: Oliveira
authors.forename: Victor
authors.initials: V
authors.lastname: De Freitas
authors.forename: Nuno
authors.initials: N
authors.lastname: Mateus
authors.forename: André
authors.initials: A
authors.lastname: Melo
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D055598:Chemical Phenomena; D005505:Food Coloring Agents / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D000872:Anthocyanins; D005505:Food Coloring Agents; D010636:Phenols