Formulation à base de nanochitosan et nanocellulose pour la préparation d'emballage alimentaire

Les exigences en termes de qualité et de sécurité lors de la transformation et de la distribution des produits alimentaires nécessitent l'utilisation d'emballages adaptés pour éviter leur dégradation et prolonger leur durée de conservation ainsi que pour préserver leurs qualités organoleptiques dans le respect des contraintes de sécurité et écologiques. Cependant, actuellement, la plupart de ces emballages plastiques sont fabriqués à partir de dérivés pétrosourcés ce qui a des conséquences délétères sur l‘environnement augmentant la production de déchets et la pollution des écosystèmes. Une approche pour surmonter ce problème consiste à remplacer les plastiques conventionnels par des matériaux biosourcés qui peuvent être produits à partir de substances naturelles qui seront dégradées dans la nature. Parmi les divers biopolymères existants, le chitosan apparaît comme un bon candidat en raison de ses propriétés antimicrobiennes et filmogènes connues qui sont favorables à des fins d'emballage. Cependant, les propriétés mécaniques des films plastiques à base de chitosan ne sont pas suffisantes et il est souvent nécessaire d'y ajouter d'autres composants tels que la cellulose pour les améliorer. De plus, récemment, il a également été décrit que l'utilisation de ces biopolymères dans leurs nanoformes pourrait grandement améliorer leurs propriétés. Cependant, l'extraction de ces biopolymères et leur transformation en nanomatériaux impliquent des procédures qui ne respectent pas toujours les principes de la chimie et des procédés verts. Dans ce travail, nous proposons le développement de protocoles plus écoresponsables basés sur les micro-ondes et les ultrasons pour produire de la nanocellulose à partir de cellulose bactérienne ainsi que du chitosan à partir de la chitine. De plus des films bioplastiques à partir de chitosane et de cellulose sont préparés et l‘impact de l'utilisation de nanoformes de ces polymères sur les propriétés du film est évalués. Pour améliorer la résistance à l'eau du film, des émulsions à la cire d'abeille ont été aussi préparées et l'impact de leurs formulations sur les propriétés du film a été étudiée. Enfin, la dynamique d'impact des gouttelettes de cette dernière formulation a été évaluée pour étudier la potentialité de son utilisation pour une application par pulvérisation.The requirements in terms of quality and safety during the processing and distribution of food products require the use of suitable packaging to prevent their degradation and extend their shelf life as well as to preserve their organoleptic qualities while respecting safety and ecological constraints. However, currently, most of these packagings are made from oil-based plastic which has defective consequences on waste generation and ecosystem pollution. One approach to overcome this issue is to replace conventional plastics with bio-based materials which can be produced from natural substances and degraded in nature. Among the various existing biopolymers, chitosan appears to be a good candidate due to its known antimicrobial and filmforming properties which are favorable for packaging purposes. However, the mechanical properties of chitosan-based plastic films are not sufficient and it is often necessary to add other components such as cellulose to them to improve their mechanical properties. Moreover, recently it has also been described that the utilization of these biopolymers in their nanoforms could greatly enhance their properties. However, the extraction of these biopolymers and their transformation into nanomaterials involve procedures that do not always comply with the principles of green chemistry and processes. In this work, we propose the development of ecological protocols based on microwaves and ultrasound to produce nanocellulose from bacterial cellulose as well as chitosan from chitin. Furthermore, we prepared bioplastic films from chitosan and cellulose and evaluated the properties of the film when using nanoforms of these polymers. To improve the water resistanceof the film, emulsions with beeswax were prepared and the impact of their formulations on the properties of the film was studied. Finally, the impact dynamics of the droplets of the latter formulation was evaluated to study the potentiality of its use for application by spraying

Nanofluid to Nanocomposite Film: Chitosan and Cellulose-Based Edible Packaging

International audienceChitosan (CH)-based materials are compatible to form biocomposite film for food packaging applications. In order to enhance water resistance and mechanical properties, cellulose can be introduced to the chitosan-based film. In this work, we evaluate the morphology and water resistance of films prepared from chitosan and cellulose in their nanoscale form and study the phenomena underlying the film formation. Nanofluid properties are shown to be dependent on the particle form and drive the morphology of the prepared film. Film thickness and water resistance (in vapor or liquid phase) are clearly enhanced by the adjunction of nanocrystalline cellulose

Nanofluid to Nanocomposite Film: Chitosan and Cellulose-Based Edible Packaging

Chitosan (CH)-based materials are compatible to form biocomposite film for food packaging applications. In order to enhance water resistance and mechanical properties, cellulose can be introduced to the chitosan-based film. In this work, we evaluate the morphology and water resistance of films prepared from chitosan and cellulose in their nanoscale form and study the phenomena underlying the film formation. Nanofluid properties are shown to be dependent on the particle form and drive the morphology of the prepared film. Film thickness and water resistance (in vapor or liquid phase) are clearly enhanced by the adjunction of nanocrystalline cellulose

Ultrasonic Irradiation Coupled with Microwave Treatment for Eco-friendly Process of Isolating Bacterial Cellulose Nanocrystals

International audienceThe isolation of crystalline regions from fibers cellulose via the hydrolysis route generally requires corrosive chemicals, high-energy demands, and long reaction times, resulting in high economic costs and environmental impact. From this basis, this work seeks to develop environment-friendly processes for the production of Bacterial Cellulose Nanocrystals (BC-NC). To overcome the aforementioned issues, this study proposes a fast, highly-efficient and eco-friendly method for the isolation of cellulose nanocrystals from Bacterial Cellulose, BC. A two-step processes is considered: (1) partial depolymerization of Bacterial Cellulose (DP-BC) under ultrasonic conditions; (2) extraction of crystalline regions (BC-NC) by treatment with diluted HCl catalyzed by metal chlorides (MnCl 2 and FeCl 3 .6H 2 O) under microwave irradiation. The effect of ultrasonic time and reactant and catalyst concentrations on the index crystallinity (CrI), chemical structure, thermal properties, and surface morphology of DP-BC and BC-NC were evaluated. The results indicated that the ultrasonic treatment induced depolymerization of BC characterized by an increase of the CrI. The microwave assisted by MnCl 2-catalyzed mild acid hydrolysis enhanced the removal of the amorphous regions, yielding BC-NC. A chemical structure analysis demonstrated that the chemical structures of DP-BC and BC-NC remained unchanged after the ultrasonic treatment and MnCl 2-catalyzed acid hydrolysis process

Study of Water Resistance of Nanochitosan-CNC Composite Film

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Modification of Physio-Mechanical Properties of Chitosan-Based Films via Physical Treatment Approach

The premise of this work is the modification of the properties of chitosan-based film for possible use in food packaging applications. The biofilm was prepared via thermal and mechanical treatment through blending polymers with chitosan using Polyvinyl Alcohol (PVA) and loading different types of chemical agents, i.e., citric acid (CA), succinic acid (SA), and tetraethoxysilane (TEOS). The modification was carried out under high-speed homogenization at elevated temperature to induce physical cross-linkage of chitosan polymer chains without a catalyst. The findings showed that PVA improved the chitosan films’ Tensile strength (TS) and elongation at break (Eb). The presence of chemicals caused an increase in the film strength for all samples prepared, in which a 5% w/w of chemical in the optimum composition CS/PVA (75/25) provided the maximum strength, namely, 33.9 MPa, 44.0 MPa, and 41.9 MPa, for CA-5, SA-5, and TEOS-5, respectively. The chemical agents also increased the water contact angles for all tested films, indicating that they promoted hydrophobicity. The chemical structure analysis showed that, by incorporating three types of chemical agents into the CS/PVA blend films, no additional spectral bands were found, indicating that no covalent bonds were formed. The thermal properties showed enhancement in melting peak and degradation temperature of the blend films, compared to those without chemical agents at the optimum composition. The X-ray diffraction patterns exhibited that PVA led to an increasing crystallization tendency in the blend films. The morphological observation proved that no irregularities were detected in CS/PVA blend films, representing high compatibility with both polymers