Applications of nanotechnology in food packaging and food safety: barrier materials, antimicrobials and sensors

Electrospun Nylon-Graphene Nanocomposites Synthesis and Microstructure

There has been much interest in the last few years on materials reinforced with nanometer scale particles. These so-called nanocomposites can exhibit hybrid properties derived from its components. One of the most promising nanocomposites is that based on polymers reinforced with single-layered carbon sheets named graphene. The reason is that graphene can significantly improve the physical properties of the polymeric material once it is completely dispersed in the matrix. In this work nylon/graphene nanocomposites were prepared starting from the synthesis of graphite oxide (GO). Direct oxidation of graphite powder was utilized to produce GO. That is, the oxidation reaction produced graphite layers with functional groups containing oxygen. The aim was to increase the polarity of GO to enable a good dispersion in polar solvents. Then, nylon/graphene nanocomposites were prepared by reducing GO in the presence of nylon. Finally, non-woven membranes, with nanometer sized filaments, of nylon/graphene were electrospun. The morphology and microstructure of the nanocomposites was investigated via electron microscopy and X-ray diffraction.

Clay-chitosan nanobrick walls: completely renewable gas barrier and flame-retardant nanocoatings

Thin films prepared via a layer-by-layer (LbL) assembly of renewable materials exhibit exceptional oxygen barrier and flame-retardant properties. Positively charged chitosan (CH), at two different pH levels (pH 3 and pH 6), was paired with anionic montmorillonite (MMT) clay nanoplatelets. Thin-film assemblies prepared with CH at high pH are thicker, because if the low polymer charge density. A 30-bilayer (CH pH 6-MMT) nanocoating (~100 nm thick) reduces the oxygen permeability of a 0.5-mm-thick polylactic acid film by four orders of magnitude. This same coating system completely stops the melting of a flexible polyurethane foam, when exposed to direct flame from a butane torch, with just 10 bilayers (~30 nm thick). Cone calorimetry confirms that this coated foam exhibited a reduced peak heat-release rate, by as much as 52%, relative to the uncoated control. These environmentally benign nanocoatings could prove beneficial for new types of food packaging or a replacement for environmentally persistent antiflammable compounds.

Food Packaging Permeability Behaviour: A Report

The use of polymer materials in food packaging field is one of the largest growing market area. Actually the optimization behaviour of packaging permeability is of crucial importance, in order to extend the food shelf-life and to reach the best engineering solution. Studying the permeability characterization of the different polymer material (homogeneous and heterogeneous polymer system) to the different packaging gases, in different environmental condition, is crucial to understand if the selected material is adapted to the chosen food contact field. Temperature and humidity parameters are of crucial importance for food quality preservation, especially in real life situations, like food market, and house long-life use. The aim of this report was to collect information about the state of the art on the permeability characteristics of the polymer packages used on food field.

Nanobiotechnologies for the detection and reduction of pathogens

Advances in the manipulation of nanomaterials has permitted the development of nanobiotechnology with enhanced sensitivities and improved response times. Low levels of infection of the major pathogens require the need for sensitive detection platforms and the properties of nanomaterials make them suitable for the development of assays with enhanced sensitivity, improved response time and increased portability. Nanobiotechnologies focusing on the key requirements of signal amplification and pre-concentration for the development of sensitive assays for food-borne pathogen detection in food matrices will be described and evaluated. The potential that exists for the use of nanomaterials as antimicrobial agents will also be examined.