Development and characterization of active edible films from aqueous extracted apple pomace pectin enriched with chicory extract and chromium oxide nanoparticles for fresh produce packaging

In this study, the impact of chicory extract (0, 7.5, 15%) and chromium oxide nanoparticles (0, 2, 4%) on the physicochemical and structural properties of apple pomace-derived pectin-based edible films were studied using response surface methodology (RSM) and the central composite designs(CCD).The results indicated that with increasing the concentrations of both chicory extract and chromium oxide nanoparticles, the moisture content decreased from 18 % to 14 %, and solubility decreased from 45 % to 30 %, while film thickness increased from 0.4 mm to 0.7 mm ( P ≤ 0.05).The tensile strength values ranged from 0.63 MPa to 1.18 MPa, with the pure pectin film showing the highest value (1.18 ± 0.03 MPa) and the film containing 15% chicory extract showing 1.12 ± 0.05 MPa, whereas films containing 4% chromium oxide nanoparticles exhibited 0.74 ± 0.01 MPa, and the combination of 15% extract and 4% nanoparticles resulted in the lowest value (0.63 MPa). Regarding color indices, increasing chromium oxide nanoparticles from 0 to 4% significantly decreased L* (from 71.6 to 52.1) and whiteness index (from 70.2 to 48.4), while increasing a* (from 2.2 to 4.4), b* (from 11.3 to 17.5), and yellowness index (from 19.6 to 47.3) (P ≤ 0.05). SEM and FTIR results indicated minor alterations in the chemical structure, strong molecular interactions within the biopolymer matrix, and effective mixing of pectin with both the extract and nanoparticles. DSC results also showed an increase in the intensity of endothermic peaks, suggesting strengthened intermolecular interactions and enhanced crystallinity within the polymer matrix.The results of the present study demonstrate that apple pomace-derived pectin films enriched with 15% chicory extract and 4% chromium oxide nanoparticles exhibit strong potential as an innovative active edible film system.