0000000000984191
AUTHOR
Thomas Karbowiak
showing 46 related works from this author
Transfer of Water and Volatiles at Interfaces: Application to Complex Food Systems
2013
International audience; During processing, storage and consumption, mass transfer of various small molecules (water, gases, flavour compounds or other solutes) occurs between the different phases in complex food products, or between complex food and its surroundings. These mass transfers can lead to physical or chemical changes and thus induce food quality modifications.The objective of this paper is to better understand the behaviour of small molecules at the interfaces, especially in model heterogeneous food systems. Different techniques have been designed to characterize mass transfers of these small molecules and their effects on food properties. In particular, techniques such as rotati…
Cloning and expression of genes involved in conidiation and surface properties of Penicillium camemberti grown in liquid and solid cultures.
2008
International audience; Based on bioinformatic data on model fungi, the rodA and wetA genes encoding, respectively, a RodA hydrophobin protein and the WetA protein involved in conidiation mechanisms, were PCR-cloned and characterized for the first time in Penicillium camemberti. These results, completed by a sequence of the brlA gene (available in GenBank), which encodes a major transcriptional regulator also involved in the conidiation mechanism, were used to compare, by qRT-PCR, the expression of the three genes in liquid and solid cultures in a synthetic medium. While expression of the brlA and wetA genes increased dramatically in both culture conditions after 4 days of growth, expressio…
Thermal Effects of Water Intrusion in Hydrophobic Nanoporous Materials.
2009
Liquid water intrusion in hydrophobic nanoporous silicalite-1, a pure siliceous zeolite, in isothermal conditions under high pressure produces an endothermic effect. After intrusion, confined water in zeolite pores is in a different state from that of the liquid bulk water. Such forced intrusion also chemically modifies the material and tends to render it slightly more hydrophilic.
Techniques to measure sorption and migration between small molecules and packaging. A critical review
2015
The mass transfer parameters diffusion and sorption in food and packaging or between them are the key parameters for assessing a food product's shelf-life in reference to consumer safety. This has become of paramount importance owing to the legislations set by the regulated markets. The technical capabilities that can be exploited for analyzing product–package interactions have been growing rapidly. Different techniques categorized according to the state of the diffusant (gas or liquid) in contact with the packaging material are emphasized in this review. Depending on the diffusant and on the analytical question under review, the different ways to study sorption and/or migration are present…
Investigation of water transfer across thin layer biopolymer films by infrared spectroscopy
2011
International audience; The investigation of the apparent diffusivity of water in thin layer iota-carrageenan-based films by FTIR-ATR spectroscopy clearly evidences the fundamental role of surface properties on water transfer. Water diffusivity in iota-carrageenan based biopolymer films ranges from 0.3 to 1.3 × 10−10 m2 s−1 and is thus 10–100 times lower than that in highly hydrated carrageenan gels. The surface heterogeneity and composition when fat is added strongly influence the diffusivity by modifying the liquid water absorption at the inner surface.This study of diffusing molecules in liquid state is particularly interesting to mimic situations where direct liquid water contact occurs…
From macroscopic to molecular scale investigations of mass transfer of small molecules through edible packaging applied at interfaces of multiphase f…
2009
Abstract This paper presents a multi-scale approach to investigate mass transfer properties of edible films that integrates some published data and new original results. The transport of small molecules, such as water, between the different parts of multiphase food products leads to quality deterioration and thus requires the use of barrier edible films or coatings. Therefore, it is necessary to characterise the properties of both food and edible barriers, like the diffusivities of their respective migrants. Surface properties characterisation of edible films, composed of an iota-carrageenan matrix in association with a high melting point fat was investigated by goniometry and allows the de…
Importance of surface tension characterization for food, pharmaceutical and packaging products: a review.
2006
This article reviews the various theoretical approaches that have been developed for determination of the surface tension of solids, and the applications to food industrial products. The surface tension of a solid is a characteristic of surface properties and interfacial interactions such as adsorption, wetting or adhesion. The knowledge of surface tension is thus of great interest for every domain involved in understanding these mechanisms, which recover a lot of industrial investigations. Indeed, it is the case for the packaging industry, the food materials science, the biomedical applications and the pharmaceutical products, cleaning, adhesive technology, painting, coating and more gener…
Influence of drug polarity upon the solid-state structure and release properties of self-emulsifying drug delivery systems in relation with water aff…
2009
To overcome low oral bioavailability of poorly water-soluble drugs, self-emulsifying drug delivery systems (SEDDS) have been noted as a promising strategy. However, incorporation of drugs into SEDDS composed of Gelucire44/14 could induce interactions not yet well understood. The aim of this study was to investigate the influence of drug polarity upon the solid-state structure of SEDDS formulation, particularly in terms of wettability, thermal behaviour and microscopic aspects and their effect upon the release properties of the SEDDS. Model drugs were naproxen and sodium naproxen (10% w/w), two drugs with similar chemical structure but different water solubilities. Both drugs had an effect o…
Protection of active aroma compound against moisture and oxygen by encapsulation in biopolymeric emulsion-based edible films.
2008
International audience; Edible films made of ι-carrageenans display interesting advantages: good mechanical properties, stabilization of emulsions, and reduction of oxygen transfers. Moreover, the addition of lipids to ι-carrageenan-based films to form emulsified films decreases the transfer of water vapor and can be considered to encapsulate active molecules as flavors. The aim of this study was to better understand the influence of the composition and the structure of the carrageenan-based film matrices on its barrier properties and thus on its capacity to encapsulate and to protect active substances encapsulated. Granulometry, differential scanning calorimetry, and Fourier transform infr…
Improved hydrophobicity of inorganic–organic hybrid mesoporous silica with cage-like pores
2013
International audience; Hydrophobic ordered mesoporous silica particles with cage-like pores (SBA-1 type) were prepared through co-condensation of phenyltriethoxysilane (PhTES) and tetraethylorthosilicate (TEOS) at different TEOS/PhTES molar ratios. It is shown that the hydrophobic character of the particles is enhanced by increasing the phenyl loading (decreasing the TEOS/PhTES molar ratio) and that it could be further enhanced by subsequent trimethylsilyl (TMS) grafting on remaining silanol groups (TMS-PhSBA-1 sample). This increase of hydrophobicity has been evidenced on the internal surface (mesoporosity) of the particles using water adsorption and, on the external surface of the partic…
Effect of plasticizers (water and glycerol) on the diffusion of a small molecule in iota-carrageenan biopolymer films for edible coating application.
2006
Translational diffusion of a fluorescein probe has been measured in iota-carrageenan edible films containing different amounts of glycerol (0, 15, 30, and 45%), using fluorescence recovery after photobleaching (FRAP) experiments. The effects of this plasticizer as well as the plasticizing effect of water on the diffusion of fluorescein have been studied in this edible coating mainly composed of natural biopolymer. Diffusion coefficients of about 10(-13) m2 s(-1) have been measured in these films for water activity (aw) lower than 0.7. Above this water content threshold, fluorescein translational diffusion coefficient increases up to 10(-12) m2 s(-1). Another interesting information obtained…
Diffusion of Oxygen through Cork Stopper: Is It a Knudsen or a Fickian Mechanism?
2014
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 …
Chemical messages in 170-year-old champagne bottles from the Baltic Sea: Revealing tastes from the past
2015
International audience; Archaeochemistry as the application of the most recent analytical techniques to ancient samples now provides an unprecedented understanding of human culture throughout history. In this paper, we report on a multiplatform analytical investigation of 170-y-old champagne bottles found in a shipwreck at the bottom of the Baltic Sea, which provides insight into winemaking practices used at the time. Organic spectroscopy-based nontargeted metabolomics and metallomics give access to the detailed composition of these wines, revealing, for instance, unexpected chemical characteristics in terms of small ion, sugar, and acid contents as well as markers of barrel aging and Maill…
Confinement of Water in Hydrophobic Nanopores: Effect of the Geometry on the Energy of Intrusion
2013
International audience; Water confinement in the hydrophobic nanopores of highly siliceous zeolite having MFI and CHA topology is investigated by high pressure manometry coupled to differential calorimetry. Surprisingly, the intrusion of water is endothermic for MFI but exothermic for CHA. This phase transition depends on the geometry of the environment in which water is confined: channels (MFI) or cavities (CHA). The energy of intrusion is mainly governed by the change in the coordination of water molecules when they are forced to enter the nanopores and to adopt a weaker, hydrogen-bonded structure. At such a nanoscale, the properties of the molecules are governed strongly by geometrical r…
Adsorption equilibria of water vapor on cork.
2010
International audience; We report here for the first time a complete thermodynamic study of water vapor adsorption on crude cork powder and plate. Adsorption−desorption isotherms were accurately measured by thermogravimetry at 283, 298, and 313 K in a large range of relative pressure. Adsorption enthalpies were determined by calorimetry as a function of loading. Adsorption−desorption isotherms exhibit a hysteresis due to the swelling of the material. The influence of the presence of lenticels on the adsorption properties of cork is found to be negligible. A detailed analysis and interpretation of adsorption data allow proposal of an adsorption mechanism in two steps. (i) First, water adsorb…
Toward Sustainable PLA-Based Multilayer Complexes with Improved Barrier Properties
2019
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…
Spectroscopic analyses of the influence of electron beam irradiation doses on mechanical, transport properties and microstructure of chitosan-fish ge…
2015
International audience; The objective of this work was to better display the effect of electron beam accelerator doses (0, 20, 40 and 60 kGy) on structural, mechanical and barrier properties of edible lightly plasticized chitosan-fish gelatin blend film. From Electron Spin Resonance (ESR), signal at 3500 G for blend film was identified as free radical formation during irradiation, which might introduce intermolecular cross-linking into the polymer matrix, thus affecting structural properties. Tensile Strength (TS) for gelatin film significantly increased with growing irradiation doses (improved by 30% for 60 kGy), but the TS of chitosan and blend films were not significantly affected. On th…
Diffusion of small molecules in edible films: Effect of water and interactions between diffusant and biopolymer
2008
Mass transfers of various molecules in multiphasic food products lead to quality modification and thus require the use of edible films or coatings in-between the foodstuff. Consequently, it is important to assess the barrier properties and efficiencies of edible films as well as to determine the diffusivities of the migrants. Translational diffusion of a reference molecule such as fluorescein, determined by the fluorescence recovery after photobleaching (FRAP) method, displays a threshold of a critical water content inducing an increase of the molecular mobility, and demonstrates that multiple populations of a single molecular specie can be involved in different diffusion kinetics. Further …
FITNESS, première plateforme européenne sur l’emballage et le conditionnement des aliments
2019
National audience; FITNESS (2017-2020) est un projet financé dans le cadre du programme européen Erasmus+. Le but de ce projet est de mettre en place une plateforme virtuelle proposant librement des contenus interactifs (présentations, guides, quizz, webinaires, outils de calcul) en lien avec l’emballage alimentaire et les problématiques de conditionnement des aliments. L’objectif est d’offrir un contenu permettant de comprendre les principes et les enjeux (modules de base), et d’apprendre des techniques plus avancées permettant de maîtriser les impacts ou la sécurité sanitaires des matériaux utilisés (modules avancés). La plateforme s’adresse aussi bien aux étudiants, enseignants et profes…
Enrobages comestibles et emballages actifs pour la conservation d’aliments périssables présentation et premiers résultats du projet de coopération Fr…
2017
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…
Sorption of n-hexane in amorphous polystyrene
2014
Sorption properties of pure n-hexane vapor in amorphous polystyrene (PS) were studied at 298 K by thermogravimetry under controlled vapor pressure. Two sorption-desorption cycles were performed by varying the relative pressure between 0 and 0.91. Mixing of PS with n-hexane resulted in a strong plasticization, which was evidenced by quite significant depression in the glass transition temperature of the polymer as shown by differential scanning calorimetry. Maximum quantity of n-hexane sorbed in the PS at 298 K and at a pressure close to saturation was about 12.4 wt %. The thermogravimetry yielded an isotherm with a strong hysteresis loop, explanation of which was hypothesized with the help …
Diffusion of oxygen in cork.
2012
International audience; This work reports measurements of effective oxygen diffusion coefficient in raw cork. Kinetics of oxygen transfer through cork is studied at 298 K thanks to a homemade manometric device composed of two gas compartments separated by a cork wafer sample. The first compartment contains oxygen, whereas the second one is kept under dynamic vacuum. The pressure decrease in the first compartment is recorded as a function of time. The effective diffusion coefficient D-eff is obtained by applying Fick's law to transient state using a numerical method based on finite differences. An analytical model derived from Fick's law applied to steady state is also proposed. Results give…
Controlled release of tyrosol and ferulic acid encapsulated in chitosan–gelatin films after electron beam irradiation
2016
Abstract This work deals with the study of the release kinetics of antioxidants (ferulic acid and tyrosol) incorporated into chitosan–gelatin edible films after irradiation processes. The aim was to determine the influence of electron beam irradiation (at 60 kGy) on the retention of antioxidants in the film, their release in water (pH=7) at 25 °C, in relation with the barrier and mechanical properties of biopolymer films. The film preparation process coupled to the irradiation induced a loss of about 20% of tyrosol but did not affect the ferulic acid content. However, 27% of the ferulic acid remained entrapped in the biopolymer network during the release experiments whereas all tyrosol was …
Sorption of 4-ethylphenol and 4-ethylguaiacol by suberin from cork
2015
International audience; Cork shows an active role in the sorption of volatile phenols from wine. The sorption properties of 4-ethylphenol and 4-ethylguaiacol phenols in hydro-alcoholic medium placed in contact with suberin extracted from cork were especially investigated. To that purpose, suberin was immersed in model wine solutions containing several concentrations of each phenol and the amount of the compound remaining in the liquid phase was determined by SPME-GC-MS. Sorption isotherms of 4-ethylguaiacol and 4-ethylphenol by suberin followed the Henry's model. The solid/liquid partition coefficients (KSL) between the suberin and the model wine were also determined for several other volat…
The cork viewed from the inside
2015
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 …
Transfer of Water and Active Molecules at the Interfaces in Complex Food Systems: Theoretical and Practical Aspects
2011
Abstract During processing, storage and consumption, mass transfer of various molecules (water, gases, flavour compounds or other solutes) occur between the different phases in complex food products, and/or also between the complex food and its surroundings. These mass transfers can lead to physical and/or chemical changes and thus induce food quality modifications. The objective of this presentation is to better understand the behaviour of small molecules at the interfaces, especially in model heterogeneous food systems. Different techniques have been developed to characterize their properties and their impact on the mass transfers. Particularly, techniques such as rotative diffusion cell …
MOOC : "Open Wine University 2"
2018
Plan du cours Semaine 1 : Introduction Entre sol et climat Micro-organismes du vin Premiers pas en dégustation + support sur la vinification des vins blancs et des vins rouges Semaine 2 : Le vin en danger ? Climat et viticulture Principales maladies et ravageurs de la vigne Economie mondiale du vin après la crise du phylloxéra Semaine 3 : Façonner le vin Géologie et sols des terroirs bourguignons Vin et diversité microbienne Marchés du vin Semaine 4 : Maîtriser son terroir Construction du terroir de la vigne Vinification des vins spéciaux : l'exemple de la production de vins jaunes du Jura Défauts du vin Semaine 5 : Mettre le vin à table Mise en bouteille du vin Vieillissement du vin Le vin…
Sorption Equilibria of Ethanol on Cork
2013
International audience; We report here for the first time a thermodynamic study of gaseous ethanol sorption on raw cork powder and plate. Our study aims at a better understanding of the reactivity of this material when used as a stopper under enological conditions, thus in close contact with a hydroethanolic solution, wine. Sorption−desorption isotherms were accurately measured by thermogravimetry at 298 K in a large range of relative pressures. Sorption enthalpies were determined by calorimetry as a function of loading. Sorption−desorption isotherms exhibit a hysteresis loop probably due to the swelling of the material and the absorption of ethanol. Surprisingly, the sorption enthalpy of e…
Wetting properties at the surface of iota-carrageenan-based edible films
2006
International audience; Surface properties of edible films composed of a polymeric matrix of carrageenan in association with hydrophobic material were studied by contact angle measurements. The use of this technique not only in a static mode but also in a dynamic way enables investigation of surface hydrophobicity as well as surface wettability. The absorption flux inside the material can be estimated from the wetting kinetic, which can be very useful to quickly compare water barrier efficiency of the tested films. Comparison of carrageenan films with films containing known amounts of additives enables understanding and correlation of changes of the surface properties with the nature of use…
Water-induced local ordering of chitosan polymer chains in thin layer films
2015
International audience; Carbon-13 NMR (CP-MAS and FSLG 1H–13C HETCOR) have been applied to chitosan salt films synthesized in acetic acid and exposed to different relative humidity environments (32% or 75%) at 20 °C for 1 month. It gives insight in the relationship between structure and functional properties according to the hydration level of this biomaterial as a film. The acetate ions trapped in the chitosan act as structuring agents between chitosan chains for the low hydration state. But, increasing the moisture content induces spontaneous removal of acetic acid and a subsequent modification in the film structure, with an increase in local ordering. HETCOR experiments also showed a mul…
New insights in the formation of silanol defects in silicalite-1 by water intrusion under high pressure.
2010
International audience; The "water-silicalite-1" system is known to act as a molecular spring. The successive intrusion-extrusion cycles of liquid water in small crystallites (6 × 3 × 0.5 μm(3)) of hydrophobic silicalite-1 were studied by volumetric and calorimetric techniques. The experiments displayed a decrease of the intrusion pressure between the first intrusion-extrusion cycle and the consecutive ones, whereas the extrusion pressures remained unchanged. However, neither XRD studies nor SEM observations revealed any structural and morphological modifications of silicalite-1 at the long-range order. Such a shift in the value of the intrusion pressure after the first water intrusion-extr…
Thermoplastic starch and green tea blends with LLDPE films for active packaging of meat and oil-based products
2019
International audience; Thermoplastic starch (TPS) is an alternative biomaterial that can be used to produce bioplastics to replace petroleum-based food packaging. Active films were developed from acetylated cassava TPS and green tea using the blown extrusion process. Green tea (GT) and TPS from native starch (NS) and acetylated starch (AS) with different degrees of substitution (DS) were extruded with linear low-density polyethylene (LLDPE) at LLDPE/TPS-GT ratios of 70/30 and 60/40 prior to blown-film extrusion. Results indicated that a higher DS of AS enhanced melt flow index which altered processability and subsequently impacted film microstructures and physical and barrier properties. N…
Sorption and diffusion properties of volatile phenols into cork
2010
International audience; The sorption and diffusion properties of seven common volatile phenols in hydro-alcoholic medium placed in contact with natural cork were investigated to determine the influence of cork closures on the concentration of these compounds in wine. Weighted cork samples were immersed in model wine solutions containing selected concentrations of each compound and were sampled over time. Sorption coefficients ranged between 125 and 306 mg of aroma compound per kg of cork, while diffusion coefficients varied from 0.8 to 4.1 × 10−11 m2/s. Sorption isotherms of guaiacol and 4-propylguaiacol, respectively, the lowest and highest sorbed compounds of an homologous series of guaia…
Measurement of transport phenomena of volatile compounds: A review
2008
International audience; Measurement of the transport phenomena of volatile compounds is a central preoccupation in food flavour and is the subject of the present paper. After a theoretical reminder concerning transport phenomena, the methods used for the measurement of diffusion and mass transfer of volatile compounds are described with their principles, main advantages and drawbacks. These methods are illustrated by some results obtained for flavoured model food products.Several methods characterized by the type of diffusion coefficient measured, the method basis, the scale at which diffusion is measured and the means used to detect the diffusing molecule, are available to determine diffus…
Role of Wood Macromolecules on Selective Sorption of Phenolic Compounds by Wood
2008
Wood is a complex structure of various macromolecules, mainly cellulose, hemicellulose, and lignin. Although the sorption process of some organic compounds by wood has been elucidated, the relative contribution of its different fractions in the sorption mechanism is not clearly determined. Certain works predict the amount of organic compounds sorbed on wood as a direct relationship to its lignin fraction. All wood macromolecules, however, seem to have the capacity to sorb organic compounds. Sorption of phenolic compounds on individual wood macromolecules has been studied and compared to that on wood. Wood-water partition coefficients ( K wood) for phenolic volatiles and their sorption rates…
Enhancement of structural, functional and antioxidant properties of fish gelatin films using Maillard reactions
2018
International audience; This study investigates the effect of Maillard reactions (MR) on the physico-chemical and biological properties of fish gelatin based edible films. Glucose was incorporated in gelatin film forming solutions at different glucose/lysine molar ratios: 0.5/1.0, 1.0/1.0 and 5.0/1.0. The MR was then induced by heating films at 90 °C for 24 h in dry conditions. Color changes and browning index measurements were used to pursue the MR kinetic. Results showed that the development of MR products was dependent on the glucose content and on the reaction time. Mechanical and thermal properties of treated films displayed an increase in tensile strength, elongation at break and glas…
Beyond Biodegradability of Poly(lactic acid): Physical and Chemical Stability in Humid Environments
2017
International audience; Poly(lactic acid) (PLA) is the most traded biodegradable and biobased material. It is largely used as ecofriendly substitute of conventional plastics. Nevertheless, one of the main limiting factors is its water sensitivity. PLA reacts with water and is hydrolyzed during time, which determines its performance. Limited information related to the hydrolysis mechanism driven by water in vapor state is available in scientific literature. Literature is mainly focused on the effects of water in liquid state. This lack of information is of significant importance, since PLA interacts with water in both phases. This work was aimed to give a full depiction of the chemical and p…
Influence of thermal process on structure and functional properties of emulsion-based edible films
2007
Abstract Synthetic food packaging is classically used to prevent mass transfer of various small molecules (water, gases, flavour compounds or solutes) between a food and its surrounding medium. In the case of composite foods, the development of edible films and coatings, applied between the different phases of this food is rising up. The increase of such food products shelf-life is indeed related to the barrier efficiency of these edible packaging against small molecules transfers. This is especially true for water transfer between compartments of different water activities in the same food, that leads to important physico-chemical changes and therefore to food quality deterioration. Film-f…
Determination of water intrusion heat in hydrophobic microporous materials by high pressure calorimetry
2010
International audience; The understanding of interactions between a solid surface and a non-wetting liquid still remains of fundamental interest in numerous research fields, from chemistry to biology. This work focuses on the mechanisms of water intrusion in hydrophobic microporous materials through the thermal analysis of the phenomenon. A specific calorimetric technique coupled to high pressure equipment has been developed to investigate equilibrium thermal effects in such thermodynamic systems from 0 to 400 MPa under isothermal conditions. First validation tests of this method were carried out by compressing degassed water in a constant volume V with successive small pressure increments …
Wine Oxidation and the Role of Cork
2009
The present review aims to show the state of the art of oxidation mechanisms occurring especially in white wines by taking into account knowledge from different fields in relation to the subject. It is therefore divided into three main parts. First, the mechanisms of oxidation relevant to white wine are discussed in the light of recent scientific literature. Next, the phenomenon of oxygen solubility in wine during the winemaking process, and in particular during bottling is stated theoretically as well as practically. Finally, the aspect of wine conservation after bottling is examined with respect to mass transfers which may occur through the closure, with a special emphasis on cork. Curren…
Impact of electron beam irradiation on fish gelatin film properties
2016
International audience; The objective of this work was to display the effect of electron beam accelerator doses on properties of plasticized fish gelatin film. Electron spin resonance indicates free radical formation during irradiation, which might induce intermolecular cross-linking. Tensile strength for gelatin film significantly increases after irradiation (improved by 30% for 60 kGy). The vapour permeability is weakly affected by irradiation. Surface tension and its polar component increase significantly and are in accordance with the increase of wettability. So, irradiation may change the orientation of polar groups of gelatin at the film surface and crosslink the hydrophobic amino aci…
Coupling tyrosol, quercetin or ferulic acid and electron beam irradiation to cross-link chitosan–gelatin films: A structure–function approach
2015
International audience; Marine industry by-products, chitosan and fish gelatin, entrapping natural antioxidants (ferulic acid, quercetin and tyrosol) were used to prepare edible active films by casting. The films were composed of chitosan and fish gelatin (1:1 w:w) and incorporating antioxidants (∼50 mg/g). After solvent evaporation (drying), the films were irradiated at 60 kGy by electron beam. This treatment aims at investigating the coupled effect of irradiation with the presence of active compound on the structure and functional properties of the films. Electron Spin Resonance (ESR) unravelled free radical formation during irradiation in films containing ferulic acid or tyrosol which fa…
Transferts de matière au travers des emballages au contact de produits alimentaires
2009
Le point sur des recherches dans le domaine des transferts de matière au travers des emballages : impact sur la qualité du produit, causes de ces transferts.
Les emballages biodégradables : durée de vie du produit ou durée de vie de l’emballage ? Exemple du PLA
2019
National audience; Parmi les matériaux d’emballages issus de ressources renouvelables, il est important de bien différencier ceux qui sont biosourcés mais non biodégradables (souvent analogues aux matériaux conventionnels pétrosourcés) de ceux qui sont à la fois biosourcés et biodégradables. Pour ces derniers, la question de leur stabilité au contact des produits alimentaires s’avère alors cruciale. Le cas du poly(lactide), ou PLA, est détaillé ici, en prenant en compte non seulement sa stabilité chimique, mais aussi sa stabilité physique. Se pose alors la question de la durée de vie de l’emballage en parallèle de celle de la durée de vie de l’aliment emballé.
Adsorption equilibria of sulfur dioxide on cork.
2009
International audience
Pla/Protein Complex Films: Multilayer Process and Properties. Matbim 2017
2017
International audience