Bio-nanocomposites for food packaging applications

There is growing interest in developing bio-based polymers and innovative process technologies that can reduce the dependence on fossil fuel and move to a sustainable materials basis. Bio-nanocomposites open an opportunity for the use of new, high performance, light weight green nanocomposite materials making them to replace conventional non-biodegradable petroleum-based plastic packaging materials. So far, the most studied bio-nanocomposites suitable for packaging applications are starch and cellulose derivatives, polylactic acid (PLA), polycaprolactone (PCL), poly(butylene succinate) (PBS) and polyhydroxybutyrate (PHB). The most promising nanoscale fillers are layered silicate nanoclays such as montmorillonite and kaolinite. In food packaging, a major emphasis is on the development of high barrier properties against the diffusion of oxygen, carbon dioxide, flavor compounds, and water vapor. Moreover, several nanostructures can be useful to provide active and/or smart properties to food packaging systems, as exemplified by antimicrobial properties, oxygen scavenging ability, enzyme immobilization, or indication of the degree of exposure to some detrimental factors such as inadequate temperatures or oxygen levels. Challenges remain in increasing the compatibility between clays and polymers and reaching complete dispersion of nanoparticles. This review focuses on the enhancement of packaging performance of the green materials as well as their biodegradability, antimicrobial properties, and mechanical and thermal properties for food packaging application. The preparation, characterization and application of biopolymer-based nanocomposites with organic layered silicate and other fillers, and their application in the food packaging sector are also discussed.