title: Adsorption of flavonoids on resins: cyanidin 3-glucoside.
abstract: Adsorption of cyanidin-3-glucoside in aqueous batch solutions was studied at pH 3.5 and 20 degrees C using 13 commercial resins with different hydrophobicity, surface areas (SA, 330-1200 m2/g), and pore radii (PR, 20-260 A). The solute affinity toward different resins was described in terms of Langmuir and Freundlich parameters; experimental data were well-fitted to the two isotherms, which were both utilized to compare resins adsorption capacity. The styrene-divinylbenzene EXA-118 resin (SA, 1200 m2/g; PR, 90 A) showed the maximum effectiveness among the tested resins; a good efficacy for removing cyanidin 3-glucoside was shown also by EXA-90 (SA, 630 m2/g; PR, 105 A). Some experiments on a styrene-divinylbenzene resin and an acrylic one demonstrated that adsorption was not influenced by pH variations of the solution within the range of 1.0-4.5. For the 10 resins having PR < or = 105 A, correlation analysis evidenced the linear increasing dependence of Freundlich constant KF on physical characteristics of surface area and pore radius. The adsorption of cyanidin 3-glucoside at 20 degrees C was compared with that of hesperidin performed in batch runs on the same resins. Moreover, the best resin (EXA-118) was tested with a sample of pigmented orange juice to assess its performance in terms of selectivity, adsorption, and desorption capabilities on a real matrix.
authors.affiliation: Dipartimento di OrtoFloroArboricoltura e Tecnologie Agroalimentari (DOFATA), Sezione Tecnologie Agroalimentari, Università degli Studi di Catania, Via S. Sofia 98, 95123 Catania, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Scordino
authors.forename: Alfio
authors.initials: A
authors.lastname: Di Mauro
authors.forename: Amedeo
authors.initials: A
authors.lastname: Passerini
authors.forename: Emanuele
authors.initials: E
authors.lastname: Maccarone
mesh_terms: D000327:Adsorption; D000872:Anthocyanins / Q000737:chemistry*; D001628:Beverages / Q000032:analysis; D002957:Citrus / Q000737:chemistry; D005419:Flavonoids / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry; D005960:Glucosides / Q000737:chemistry*; D006569:Hesperidin / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012117:Resins, Synthetic / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D005960:Glucosides; D012117:Resins, Synthetic; C462279:cyanidin-3-O-beta-glucopyranoside; D006569:Hesperidin