Search results for " Packaging"
showing 10 items of 201 documents
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…
Influence of the physical state of water on the barrier properties of hydrophilic and hydrophobic films.
2000
Water transfer through different films, as a function of the physical state of water in contact with the film, the relative humidity difference, and the water vapor pressure difference, was investigated. The films were two synthetic packagings (hydrophobic polyethylene and hydrophilic cellophane) and an edible film. The physical state of water affects water sensitive films, such as cellophane, inducing a higher liquid water transfer due to interactions with the polymer. For hydrophobic polymers, such as polyethylene, neither the physical state of water nor the relative humidity has an influence on the water permeability. In complex system, such as an edible film composed of hydrophilic part…
Effect of natural antioxidants and modified atmosphere packaging in preventing lipid oxidation and increasing the shelf-life of common dolphinfish (C…
2015
We investigated the effects of natural antioxidants and modified atmosphere packaging (MAP) on the quality and shelf-life of Coryphaena hippurus (common dolphinfish) fillets. Fillets of the control group (CO) were simply placed on trays and not sealed. Fillets of the second group (MAP) were preserved in modified atmosphere (45% CO2, 50% N2, 5% O2), and fillets of the third group (MAP-AOX) were preserved by combining natural antioxidants from halophytes with modified atmosphere. All samples were stored in a refrigerator at 1 ± 0.5 C for 18 days. Analyses were conducted at T0 and after 3, 6, 12, 15 and 18 days of storage. According to sensory tests and colour analyses, the fillets in the MAP …
Plasmonic optical sensors printed from Ag–PVA nanoinks
2014
In this paper we report on the use of a nanocomposite based on silver nanoparticles embedded in PVA as a plasmonic optical sensor to detect and quantify trace amounts of amines in gas and water, respectively. The transduction mechanism of the sensor is based on the changes of the LSPR band of Ag NPs when analyte molecules are chemisorbed on their surface. The Ag–PVA sensors are fabricated by means of a high-precision microplotter, a direct-write technology developed for printing materials from solution. The nanoink is formulated with a metal precursor (AgNO3) and a polymer (PVA) using an adequate mixture of solvents to meet the rheological requirements for the fluid dispensing process. The …
Rheological Behavior Under Shear and Non-Isothermal Elongational Flow of Biodegradable Polymers for Foam Extrusion
2013
The production of many items, in particular for food packaging applications, is based on foam extrusion and thermoforming. These operations require the use of polymers which can grant some specific rheological properties, both under shear and elongational flow. In this work, the behavior of some biodegradable polymers [Mater-Bi® and poly(lactic acid)] under shear and non-isothermal elongational flow was investigated and compared with a traditional, non-biodegradable polymer, in order to assess their suitability for industrial-scale foam extrusion and thermoforming. The rheological characterization evidenced the differences between the different biodegradable polymers and the reference polys…
Microbiological and ageing performance of polyhydroxyalkanoate-based multilayer structures of interest in food packaging
2014
Polyhydroxyalkanoates undergo crystallization during film processing and storage. In this paper, the physico–chemical ageing properties of multilayer structures based on a commercial polyhydroxybutyrate (PHB) and a polyhydroxybutyrate-co-valerate copolymer with 3% valerate content (PHBV3), containing a nanostructured zein interlayer, were analysed. The microbiological safety of the films was also evaluated by monitoring the growth of an inoculum of Listeria monocytogenes over time. Polyethyleneglycol (PEG) was added to PHBV3 films to facilitate handling as the PHBV3 mutlilayer systems (without plasticizer) cracked during film-formation. Crystallinity, thermal, mechanical, barrier and optica…
EFFECT OF ULTRASOUND TREATMENT ON PROPERTIES OF GLUTEN-BASED FILM
2010
Abstract Gluten films obtained in acid conditions display some protein dispersion difficulties. Ultrasound treatment (UT) could represent an interesting strategy for improving gluten film appearance. Different UT exposure times were applied to film-forming dispersion. The aim of this work was to investigate the effect of ultrasound treatment on gluten-based films at molecular and mesoscopic levels. Distribution in gliadin and glutenins was determined with SE-HPLC. The UT improved protein dispersion and final film appearance. Sonication did not lead to large changes in various gluten fractions, which suggests absence of important protein breakdown at the molecular level. Gluten showed high t…
A Headful of T4 Coliphage DNA Packaged to Fasces-Like Globules in Fractal Models
1998
We present a new model for T4 DNA packaging based on fractal considerations. The proposed model is based on electron microscopic observations of spread and packaged DNA. The model takes into account enzymatically and unidirectionally driven packaging, and quick release of the DNA during infection. We also consider the different biochemical reactions of the packaging process.
Effects of Tray-Drying on the Physicochemical, Microbiological, Proximate, and Sensory Properties of White- and Red-Fleshed Loquat (Eriobotrya Japoni…
2022
Loquat fruits, highly valued by consumers for their characteristic aroma and pleasant taste, have a short post-harvest life and are susceptible to mechanical damage, loss of firmness, and initial organoleptic characteristics. The aim of this work was to develop a drying method suitable for storing loquat fruits in polyamide/polyethylene (PA/PE) bags containing two gaseous mixtures (treatments): MAPN2 (100% N2) and MAPP (21% O2 and 0.04% CO2), at room temperature (20 ± 1 °C) for at least 2 months. The effects of these conditions on the physico-chemical, microbiological, proximate, and sensory properties of fruit stored over a 50-day time interval were studied. The results showed that convect…
Food Security Is None Of Your Business? Food Supply Chain Management In Support Of A Sustainable Food System
2017
Food security is the principal outcome of any given food system and it can be defined in terms of a sustainable food system where the core goal is to feed everyone sustainably, equitably and healthily. A sustainable food system addresses needs for availability, affordability and accessibility, is diverse, ecologically-sound and resilient, and builds the capabilities and skills necessary for future generations. This paper identifies the essential elements of food supply chain management in support of a sustainable food system, which ultimately enhances food security. The existing food supply chain and food system literature is synthesized in order to study the correspondence between public i…