Versatile biobased biocidal nanomaterial for a safer‐by‐design coated food packaging

International audience ; The preservation of food products using packaging with antimicrobial properties is a major challenge. Using a simple dipping procedure, we propose to functionalize the surface of commercial polypropylene (PP) films with various hybrid components based on biopolymers with silver nanoparticles (AgNPs) that are known for their bactericidal properties. The chosen biopolymers are polysaccharides in solid form such as cellulose nanocrystals (CNC) and chitin nanocrystals (ChiNC), as well as hydrosoluble molecules such as alginate and chitosan for which some OH groups serve as nucleation points for AgNPs. The successful coating was demonstrated via the presence of biopolymers on the PP film surface using electron and fluorescence microscopies. The effective presence of AgNPs on the PP film was then confirmed by atomic absorption spectroscopy measurements. Migration tests performed over 10 days made it possible to track the kinetic release of Ag+ in a food simulant. A persistent and increasing release over time was observed, especially for hybrids in solid form (i.e., CNC/AgNP, ChiNC/AgNP), bearing the smaller AgNPs (20 nm). The maximum value of Ag + released was similar to 0.30 mg Ag/kg, which is significantly lower than the value authorized by international organizations.