Search results for "Chemical engineering"
showing 10 items of 5892 documents
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…
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…
Lipid multilayered particles: the role of chitosan on structure and morphology
2010
Multilayered nanovectors made up from a controlled binary lipid mixture (POPC and DMPS) and trimethyl chitosan (TMC) have been prepared and characterized by light- and small angle neutron scattering. The morphology and the multilayer structure of the particle outer shell has been described in detail. By varying the amount of TMC in the starting solution it is possible to tune the overall surface particle charge as well as its multilamellarity. In this way the drug loading/release properties of the particles can be controlled. Therefore the use of controlled POPC/DMPS mixtures can be a valid alternative to commercial lecithin to obtain nanovectors with specific release properties.
Understanding the Effects of Crosslinking and Reinforcement Agents on the Performance and Durability of Biopolymer Films for Cultural Heritage Protec…
2021
In the last two decades, the naturally occurring polysaccharides, such as chitosan and pectin, have gained great attention having potential applications in different sectors, from biomedical to new generation packaging. Currently, the chitosan and pectic have been proposed as suitable materials also for the formulation of films and coatings for cultural heritage protection, as well as packaging films. Therefore, the formulation of biopolymer films, considering only naturally occurring polymers and additives, is a current challenging trend. This work reports on the formulation of chitosan (CS), pectin (PC), and chitosan:pectin (CS:PC) films, also containing natural crosslinking and reinforce…
Bionanocomposite films containing halloysite nanotubes and natural antioxidants with enhanced performance and durability as promising materials for c…
2020
In the last decade, the interest toward the formulation of polymer films for cultural heritage protection continuously grew, and these films must be imperatively transparent, removable, and should not react/interact with surface of the artworks. In this research, bionanocomposite films, based on chitosan (Ch) and pectin (P) and containing naturally occurring fillers and antioxidants, were formulated by solvent casting methods and were accurately characterized. The natural halloysite nanotubes (HNT) have a two-fold role, specifically, physical compatibilizer and antioxidant carrier. Therefore, the theoretical solubility between Ch and P was estimated considering Hoy&rsquo
Effect of oxidoreduction potential and of gas bubbling on rheological properties and microstructure of acid skim milk gels acidified with glucono-del…
2009
Milk oxidoreduction potential was modified using gases during the production of a model dairy product and its effect on gel setting was studied. Acidification by glucono-delta-lactone was used to examine the physicochemistry of gelation and to avoid variations due to microorganisms sensitive to oxidoreduction potential. Four conditions of oxidoreduction potential were applied to milk: milk was gassed with air, nongassed, gassed with N(2), or gassed with N(2)H(2). The rheological properties and microstructure of these gels were determined using viscoelasticimetry, measurement of whey separation, and confocal laser scanning microscopy. It appeared that a reducing environment led to less-aggre…
Pellets based on polyuronates: Relationship between gelation and release properties
2017
International audience; Three polyuronates: amidated low methoxyl pectin (ALMP), low methoxyl pectin (LMP) and polygalacturonic acid (PGA) were used to encapsulate rutin in pellets, and they were characterized by different techniques (macroscopic properties, Calcium and rutin release). The ability of the three polyuronates to bind calcium ions and the viscoelastic properties of gels were performed to relate the properties of the pellets to the gel structures. The pellets size, the water content, the water uptake, the release of calcium and rutin varied depending on the polyuronate used. The pellets size of ALMP were smaller than LMP and PGA with a lower water content, but this matrix was mo…
Integral Extraction of Opuntia ficus-indica Peel Bioproducts via Microwave-Assisted Hydrodiffusion and Hydrodistillation
2019
The microwave-assisted hydrodiffusion extraction process affords high quality pectin and betanin from the peel of red and green Opuntia ficus-indica fruits under mild conditions. An aqueous mixture of valued bioproducts is readily obtained from the fruit peel cell water itself, without any water addition. The integral extract can be used as such to formulate nutraceutical beverages and products or, upon straightforward separation, to isolate pectin and betanin devoid of chemical contaminants suitable as ingredients for products ranging from food and beverage to cosmetic and pharmaceutical sectors. Betanin shows exceptional stability thanks to the high amounts of antioxidant polyphenols in t…
Maltose-conjugated chitosans induce macroscopic gelation of pectin solutions at neutral pH
2014
Injectable polymer scaffolds are particularly attractive for guided tissue growth and drug/cell delivery with minimally invasive intervention. In the present work, "all-polymeric" gelling systems based on pectins and water-soluble maltose-conjugated chitosans (CM) have been developed. Maltose-conjugated chitosan has been synthesized at three different molar ratios, as evaluated by FITR analysis and fluorimetric titration. A thorough rheological characterization of the blends and their parent solutions has been performed. Macroscopic gelation has been achieved by mixing the high esterification degree pectins with CM at higher maltose grafted to chitosan contents. Gels form in a few minutes a…
How composition and process parameters affect volatile active compounds in biopolymer films
2012
Abstract Active edible films based on chitosan and containing an active aroma compound have been investigated. The influence of the composition of the film forming solution (solvent, plasticizers, nanoparticles, emulsifiers and aroma traps) and process parameters (temperature and viscosity) on drying kinetics, water content, colour, aroma compound retention and partition coefficient was studied. Solvent evaporation rate was increased by addition of ethanol. Water evaporation was delayed by glycerol. The aroma retention during film drying was directly related to the water content. The drying temperature had opposite influences according to the composition of the solvent and additives. Increa…