0000000000984189
AUTHOR
Aurélie Lagorce-tachon
Diffusion of Oxygen through Cork Stopper: Is It a Knudsen or a Fickian Mechanism?
International audience; 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 …
Toward Sustainable PLA-Based Multilayer Complexes with Improved Barrier Properties
Poly(lactic acid) or PLA is currently considered as one of the most promising substitutes of conventional plastics, with low environmental impact, especially for food packaging applications. Nevertheless, some drawbacks, such as high permeability to oxygen, are still limiting its industrial applications. The objective of this study was to highly increase the oxygen barrier performance of PLA without compromising its sustainable nature and following the principles of circular economy perspective. Coproducts coming from mill industries, such as wheat gluten proteins (WG), were used to produce PLA-WG-PLA multilayer complexes with improved barrier performance. Different technologies of industri…
Enrobages comestibles et emballages actifs pour la conservation d’aliments périssables présentation et premiers résultats du projet de coopération Franco-Thaïlandaise ActiFoodCoat
International audience; Les différentes étapes pour la préparation de films à base de biopolymères contenant des biomolécules antimicrobiennes et/ou antioxydantes applicables pour la conservation d’aliments périssables sont illustrées par les études réalisées par 4 équipes de recherche associées à un programme de coopération Franco-Thaïlandaise. Ces grandes étapes sont : (i) le choix de la formulation des ingrédients entrant dans la composition du film, (ii) les paramètres associés aux procédés d’élaboration des films, (iii) la caractérisation des propriétés physico-chimiques des films et l’évaluation in vitro de leur activité antimicrobienne ou antioxydante et (iv) leur application in situ…
The cork viewed from the inside
International audience; Cork is the natural material stripped from the outer bark of cork oak. It is still the most used stopper to seal wine bottles and to preserve wine during storage. Cork stoppers are sorted in different classes according to apparent defects, named lenticels, which can be related to the cork macroporosity. The more lenticels there are, the worst cork quality is. The present work aims at investigating defects analysis of cork stoppers from two classes by comparing images recorded by digital photography and neutron imaging. Surface analysis of defects obtained from photography leads to more surface defects in class 4 (6.7%) than in class 0 (4.1%). Neutron radiography and …
Pla/Protein Complex Films: Multilayer Process and Properties. Matbim 2017
International audience
Mechanical properties, internal structure and transport mechanism of oxygen in cork
During the post bottling aging, premature oxidation reactions could occur and the oxygen barrier properties of the stopper are often pointed out. Nowadays, the internal structure of this material or the effect of hydration on its mechanical properties are still undetermined. Moreover, regarding the barrier properties, the limiting step of the oxygen transfer was not yet fully understood as well as the effect of compression or the role of the glass/cork interface in a bottleneck. The study of the internal structure of cork stopper allowed us to visualize the macroporosity of the material and conclude that there is no interconnectivity between lenticels, for the two qualities studied. The eff…