title: Spectrophotometric study of the copigmentation of malvidin 3-O-glucoside with p-coumaric, vanillic and syringic acids.
abstract: Anthocyanins are a natural source of pigments in plants and their processed food products have become attractive and excellent candidates to replace the synthetic colourants due to their characteristic intense colours and associated health benefits. The intermolecular copigmentation between anthocyanins and other colourless compounds has been reported to be an important way to enhance and stabilise the colour intensity of aqueous solutions. In the present work we report the equilibrium constant, stoichiometric ratio and the thermodynamic parameters (ΔG°, ΔH° and ΔS°) related to the intermolecular copigmentation reactions of the anthocyanin malvidin 3-O-glucoside with one hydroxycinnamic acid (p-coumaric acid) and two O-methylated hydroxybenzoic acids (vanillic and syringic acid). Different factors which affect their interactions such as copigment concentration, pH and temperature of the medium are examined at two pH levels (pH=2.50 and 3.65) corresponding to those of the major food mediums where these reactions take place (fruit juices, wine, jams etc.).
authors.affiliation: Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Ponte Pietro Bucci Cubo 14/C, I-87036 Arcavacata di Rende (CS), Italy. nmalaj@unical.it
authors.forename: Naim
authors.initials: N
authors.lastname: Malaj
authors.forename: Bruna Clara
authors.initials: BC
authors.lastname: De Simone
authors.forename: Angelo Domenico
authors.initials: AD
authors.lastname: Quartarolo
authors.forename: Nino
authors.initials: N
authors.lastname: Russo
mesh_terms: D000872:Anthocyanins / Q000737:chemistry*; D003373:Coumaric Acids / Q000737:chemistry*; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D005960:Glucosides / Q000737:chemistry*; D007700:Kinetics; D010860:Pigments, Biological / Q000737:chemistry*; D013053:Spectrophotometry; D013816:Thermodynamics; D014641:Vanillic Acid
chemical_list: D000872:Anthocyanins; D003373:Coumaric Acids; D005960:Glucosides; D010860:Pigments, Biological; C065861:malvidin; D005707:Gallic Acid; C458419:malvidin-3-glucoside; C001945:syringic acid; D014641:Vanillic Acid
keywords: Copigmentation; Malvidin 3-O-glucoside (oenin); Natural food colourants; Spectrophotometry; Thermodynamic parameters (ΔG°, ΔH° and ΔS°); p-Coumaric, vanillic and syringic acids