Development of active and nanotecnology-based intelligent edible packaging systems: physical-chemical characterization

Intelligent and active packaging, using edible and biodegradable biopolymers, appears in the last years as one of the most promising applications to food packaging. However, the release of antimicrobial substances from these biopolymers is generally achieved through passive diffusion mechanisms so that there is no real effective control of the process, being necessary to design systems that allow the controlled released as a response to environmental changes. It has been demonstrated that Poly(N-isopropylacrylamide) (PNIPA) nanohydrogels can protect natamycin from hostile environments and allows a smart natamycin release utilizing environmental stimuli. This work aims at characterizing polysaccharide-based films without (GA) and with the incorporation of free natamycin (GA-NA) and natamycin-loaded PNIPA nanohydrogels (GA-PNIPA). Transport (water vapor, oxygen, and carbon dioxide permeabilities) and mechanical properties (tensile strength and elongation-at-break), opacity and water sensitivity (moisture content and contact angle) were studied, being the chemical interactions studied by mean of FTIR; SEM analyses were performed in order to verify the presence of natamycin and nanohydrogel particles in the film matrix. Results show that natamycin and natamycin-loaded PNIPA nanohydrogels can be successfully added to edible films without changing their main properties. However, tensile strength decreased (p