Composite films biobased on Prosopis nigra polysaccharide for potential sustainable food packaging

This study explores the use of plant-derived polysaccharides to develop bio-based films for food-packaging applications. A film-forming solution composed of Prosopis nigra biopolymer (PN-B), carboxymethyl cellulose (CMC), and glycerol was optimized by central composite design (CCD), resulting in two formulations: P1 and P11. The films were subsequently functionalized with silver nanoparticles (AgNPs) synthesized via chemical and biological routes. Morphological analyses revealed differences between film types, as well as structural changes following AgNPs incorporation. The addition of nanofillers increased maximum elongation by approximately 150 % in the P1 series and 450 % in the P11 series, while reducing tensile strength. AgNPs incorporation also decreased luminosity and nearly eliminated UV transmittance, indicating strong UV barrier potential. Water-vapor permeability was dependent on film structure, reaching values around 6.05 × 10^-10 g m^-1 s^-1 Pa^-1. Antimicrobial assays demonstrated inhibition zones in films containing biologically synthesized AgNPs, while chemically synthesized AgNPs films showed no activity, suggesting different nanoparticle dispersion and polymer interactions. These findings highlight the potential of PN-B/CMC-based films as sustainable packaging materials with enhanced mechanical, barrier, and antimicrobial properties.