Materials reinforced with nanocellulose: promising nanocomposites for food packaging?

The development of new packaging materials offering new functionalities and lower environmental impact, is now an urgent need. On one hand, the shelf life extension of packaged products can be an answer to the exponential increase of worldwide demand for food. On the other hand, the increase in the price of crude oil, together with the uncertainty related to its durability, has imposed the necessity to manufacture new structures to replace oil-derived polymers in the future. Finally, consumers' awareness towards environmental issues increasingly pushes industries to look with renewed interest to “green” solutions. Thus, in the last years’ numerous polymers have been exploited to develop biodegradable food packaging materials. The usage of biopolymers has been limited due to the poor mechanical and barrier properties. These properties can be enhanced by adding reinforcing nano-sized compounds to form nanocomposites. Cellulose is probably the most used and well-known renewable and sustainable raw material. The mechanical properties, reinforcing capabilities, abundance, low density and biodegradability of the cellulose nanoparticles make them ideal candidates for the processing of polymer nanocomposites. The present review focuses on the combination of nanocellulose with polymers such as wheat gluten; starch, gelatine; agar; polyvinyl alcohol (PVA); chitosan. The methods of processing, level of incorporation and the enhanced material properties are discussed. Future trends are addressed namely regarding regulations and food industry applications.This work was supported by the research project “Development of methodologies to evaluate polymeric food packaging constituents and determination of their structural and mechanical properties” (2016DAN1289) funded by the National Institute of Health Dr Ricardo Jorge, I.P. (Lisbon, Portugal).N/