title: Diffusion of oxygen through cork stopper: is it a Knudsen or a Fickian mechanism?
abstract: The aim of this work is to identify which law governs oxygen transfer through cork: Knudsen or Fickian mechanism. This is important to better understand wine oxidation during post-bottling aging. Oxygen transfer through cork wafers is measured at 298 K using a manometric permeation technique. Depending on the mechanism, we can extract the transport coefficients. Increasing the initial pressure of oxygen from 50 to 800 hPa leads to a change in the values of the transport coefficients. This implies that oxygen transport through cork does not obey the Knudsen law. From these results, we conclude that the limiting step of oxygen transport through cork occurs in the cell wall following Fickian law. From the diffusion dependence's coefficients with pressure, we also extract by applying transition state theory an apparent activation volume of 45 ± 4 nm(3). This high value indicates that oxygen molecules also diffuse from one site to another by passing through a gas phase.
authors.affiliation: UMR A 02.102 PAM Équipe PAPC Agrosup Dijon, Université de Bourgogne , 1 esplanade Erasme, F-21078 Dijon, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Lagorce-Tachon
authors.forename: Thomas
authors.initials: T
authors.lastname: Karbowiak
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Simon
authors.forename: Régis
authors.initials: R
authors.lastname: Gougeon
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bellat
mesh_terms: D055598:Chemical Phenomena; D004058:Diffusion; D018857:Food Packaging / Q000295:instrumentation*; D005740:Gases; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D010539:Permeability; D029963:Quercus; D013816:Thermodynamics; D014920:Wine
chemical_list: D005740:Gases; D010100:Oxygen
keywords: activation volume; cork stopper; diffusion; oxygen transport; permeation