Active gelatin/cress seed gum-based films reinforced with chitosan nanoparticles encapsulating pomegranate peel extract: Preparation and characterization

The aim of this study was to evaluate the effect of chitosan nanoparticles (CSNPs) incorporating pomegranate peel extract on properties of composite gelatin/cress seed gum films. The moisture barrier properties of active films were improved by 65% as function of adding CSNPs. Water contact angle (WCA) measurement exhibited hydrophobic surfaces with WCA of 108–119°. Reinforced films with 6% CSNPs showed enhanced mechanical properties, as tensile strength and elongation at break were significantly increased and decreased, respectively by 50%. Moreover, the films exhibited 85% light transmittance (T600) compared to that of control film (94%). Scanning electron microscopy revealed homogenous distribution of nanoparticles within film matrix. Atomic force microscopy showed a considerable increase in the roughness of nanocomposite films, where average surface (Ra) and root mean squared (Rq) roughness indices were increased from 0.4 and 0.5 nm in the neat gelatin film to 11.8 and 16.0 nm in gelatin/gum films with 6% CSNPs. X-ray diffraction analysis indicated that the semi-crystalline structure of composite films was not changed as function of adding CSNPs. Thermal stability of nanocomposite films was enhanced when higher contents of CSNPs were added, attributing to the interaction of CSNPs with gelatin matrix. Nanocomposite films showed no appreciable antimicrobial properties, whereas they revealed strong DPPH radical-scavenging activities.