Liger-Belair Gérard, Topgaard Daniel, Voisin Cédric, Jeandet Philippe
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.
Langmuir. 2004 May 11;20(10):4132-8. doi: 10.1021/la049960f.
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.
在本文中，通过受阻因子修正的二氧化碳溶解分子的本体扩散系数，估算了溶解于水中的二氧化碳分子穿过水合纤维素纤维壁的横向扩散系数D⊥。假设纤维壁中纤维素微纤丝之间的多孔网络被液体饱和。我们从先前关于纤维素纤维中水的自扩散的核磁共振实验中获取信息，以得出二氧化碳分子穿过纤维壁的横向扩散系数的量级。提出了约D⊥≈0.2D0的值，其中D0是二氧化碳分子在液体本体中的扩散系数。由于在倒入碳酸饮料的玻璃杯中，大多数气泡成核位置是从周围空气中漂浮过来或擦拭过程中残留的纸张或布料上脱落的纤维素纤维，因此该结果直接适用于香槟和起泡酒中二氧化碳气泡形成的动力学。如果纤维素纤维壁对溶解的二氧化碳分子不可渗透，则表明起泡动力学将比实际情况慢约三倍。
