A new nanocomposite based on LASiS-generated CuNPs as a preservation system for fruit salads

In this work, nanocomposites based on polyethylene oxide (PEO) and copper nanoparticles (CuNPs) for food packaging application were developed as new active packaging for fresh foodstuffs. Copper colloids were synthesized by femtosecond-pulsed laser ablation synthesis in solution (LASiS) using an organic environment, to ensure a good solubility of nanocolloids in polymeric solution. CuNPs were incorporated in a biodegradable polymer matrix for the preparation of composite films. Besides a deep morphological and spectroscopic characterization, bioactive ions release over time from composite thin films was studied by atomic absorption spectroscopy. Finally, in vivo tests on fresh-cut fruit were carried out to assess the effects of these nanocomposite systems on product quality. CuNPs-PEO composites were found effective to prevent quality decay of fruit salad. In particular, the active films allowed better preserving color and texture of fruit that remained acceptable for 3-4 days more than the control sample.