Nanocomposites for food packaging applications

Abstract

a b s t r a c tMost materials currently used for food packaging are non-degradable, generating environmental problems. Several biopolymers have been exploited to develop materials for eco-friendly food packaging. However, the use of biopolymers has been limited because of their usually poor mechanical and barrier properties, which may be improved by adding reinforcing compounds (fillers), forming composites. Most reinforced materials present poor matrix-filler interactions, which tend to improve with decreasing filler dimensions. The use of fillers with at least one nanoscale dimension (nanoparticles) produces nanocomposites. Nanoparticles have proportionally larger surface area than their microscale counterparts, which favors the filler-matrix interactions and the performance of the resulting material. Besides nanoreinforcements, nanoparticles can have other functions when added to a polymer, such as antimicrobial activity, enzyme immobilization, biosensing, etc. The main kinds of nanoparticles which have been studied for use in food packaging systems are overviewed, as well as their effects and applications.

Potential Applications of Chitosan Nanoparticles as Novel Support in Enzyme Immobilization

“…Over the last decade, a number of potential products based on chitosan have been increasingly produced and applied in several areas such as: waste water treatment, due to its high adhesive and insolubility properties (e.g., removal of heavy metal ions and membrane purification processes); food industries (e.g., anticholesterol and fat binding, preservative, packaging material and animal feed additive); agriculture (e.g., seed and fertilizer coating, controlled agrochemical release); pulp and paper industries, because of its wet strength to paper (e.g., surface treatment, photographic paper) and cosmetics and toiletries due to its fungicidal and fungistatic properties (e.g., moisturizer, body creams, bath lotion) (Krajewska, 2004;Nakorn, 2008;Azeredo, 2009). Fibers made of chitosan are useful as absorbable sutures and wound dressing materials (Nakajima et al, 1984).…”

“…Nanotechnology is the ability to work on a scale of about 1-100 nm in order to understand, create, characterize and use material structures, devices and systems with new properties derived from their nanostructures (Azeredo, 2009 Reducing the particle size of materials is an effective method for improving their properties. Nanoparticles have proportionally larger surface area and consequently more surface atoms than their microscale counterpart, which in turn affects their physico-chemical, optical, catalytic and other reactive properties (Rai et al, 2009).…”

“…Nanoparticles have proportionally larger surface area and consequently more surface atoms than their microscale counterpart, which in turn affects their physico-chemical, optical, catalytic and other reactive properties (Rai et al, 2009). In polymer composites conjugated with nanoparticles, a uniform dispersion of nanoparticles leads to a very large matrix/filler interfacial area, which changes the molecular mobility, the relaxation behavior and the consequent thermal and mechanical properties of the materials (Azeredo, 2009). In contrast to other biopolymers, chitosan is a hydrophilic polymer with positive charge that comes from weak basic groups, which give it special characteristics from the technological point of view (Lopez-Leon et al, 2005).…”

“…In contrast to other biopolymers, chitosan is a hydrophilic polymer with positive charge that comes from weak basic groups, which give it special characteristics from the technological point of view (Lopez-Leon et al, 2005). Recently, chitosan nanoparticles have attracted great attention in several fields due to their unique physicochemical and biological properties (Azeredo, 2009;Racovita et al, 2008;Shi et al, 2011a). …”

“…In the last decades, immobilized enzymes onto nanoparticles have been also considered for biosensors and food packaging applications (Nakorn, 2008;Azeredo, 2009). Applications of chitosan nanoparticles in immobilization of some enzymes are summarized in Table 4.…”