title: Is the wall of a cellulose fiber saturated with liquid whether or not permeable with CO2 dissolved molecules? Application to bubble nucleation in champagne wines.
abstract: In this paper, the transversal diffusion coefficient D perpendicular of CO2 dissolved molecules through the wall of a hydrated cellulose fiber was approached, from the liquid bulk diffusion coefficient of CO2 dissolved molecules modified by an obstruction factor. The porous network between the cellulose microfibrils of the fiber wall was assumed being saturated with liquid. We retrieved information from previous NMR experiments on the self-diffusion of water in cellulose fibers to reach an order of magnitude for the transversal diffusion coefficient of CO2 molecules through the fiber wall. A value of about D perpendicular approximately 0.2D0 was proposed, D0 being the diffusion coefficient of CO2 molecules in the liquid bulk. Because most of bubble nucleation sites in a glass poured with carbonated beverage are cellulose fibers cast off from paper or cloth which floated from the surrounding air, or remaining from the wiping process, this result directly applies to the kinetics of carbon dioxide bubble formation from champagne and sparkling wines. If the cellulose fiber wall was impermeable with regard to CO2 dissolved molecules, it was suggested that the kinetics of bubbling would be about three times less than it is.
authors.affiliation: Laboratoire d'OEnologie et de Chimie Appliquée, UPRES EA 2069, URVVC, Faculté des Sciences de Reims, Moulin de la Housse, B.P. 1039, 51687 Reims, Cedex, France. gerard.liger-belair@univreims.fr
authors.forename: Gérard
authors.initials: G
authors.lastname: Liger-Belair
authors.forename: Daniel
authors.initials: D
authors.lastname: Topgaard
authors.forename: Cédric
authors.initials: C
authors.lastname: Voisin
authors.forename: Philippe
authors.initials: P
authors.lastname: Jeandet