Valorizing citrus fruit into chitosan-MgO nanocomposites: engineering UN SDGs-aligned sustainable active food packaging

The current study presents a green approach for developing sustainable and biodegradable chitosan (CH) films enhanced with Magnesium Oxide nanoparticles (MgO NPs), utilizing lemon juice (LJ) and lemon peel extract (LPE). This work aims to engineer active films with improved mechanical, barrier, and water-soluble properties for food packaging applications. The films were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and mechanical testing. FTIR confirmed the successful incorporation of MgO NPs into the CH matrix via M–O vibrational peaks, while SEM revealed MgO NPs acting as structural fillers. The films showed improved mechanical properties with the tensile strength increasing from 0.6 MPa to 1.02 MPa upon incorporation of 1.5% MgO NPs. Water solubility increased from 26.8% (pure CH) to 31.6% (1.5% MgO-CH), indicating enhanced biodegradability. MgO NPs also filled polymeric matrix voids, improving barrier properties. Additional analyses included color, water vapor permeability (WVP), moisture content (MC), and swelling degree (SD). This integrated green-chemistry approach demonstrates the valorization of citrus waste into functional active packaging. The MgO NP-reinforced CH films serve as a sustainable alternative to conventional plastics, directly contributing to UN SDG 12 (Responsible Consumption) and SDG 2 (Zero Hunger) by reducing plastic pollution and food spoilage.