ZnO and Fe2TiO5 nanoparticles obtained by green synthesis as active components of alginate food packaging films

The aim of this study was to develop an active alginate packaging film incorporating antioxidant Fe2TiO5 and antibacterial ZnO nanoparticles, obtained by green synthesis utilizing citrus peel waste. The average particle size was estimated as 10 nm for ZnO and 50 nm for Fe2TiO5. Films were prepared using 2.33% (w/v) sodium alginate with 0.11% (w/v) Fe2TiO5 and/or ZnO nanoparticles. The inclusion of nanoparticles resulted in a noticeable colour difference, reduced the transparency, increased UV light protection and improved thermal stability of the film. The dry matter content of the films was around 83%. Film solubility in distilled water was low (< 8%) mainly reflecting crosslinking of the alginate polymer and Ca2+-ions. The lowest swelling degree was obtained for the ZnO/Fe2TiO5 –alginate film (178%). The efficiency of these packaging films was demonstrated through preservation of strawberry freshness. Alginate packaging film with a mixture of metal oxide nanoparticles can facilitate food safety and increase food shelf life.