Low-Impact Nanocomposite Packaging: Cu@Nanocellulose-Fortified Chitosan/PVA/Honey Bioactive Film for Strawberry Preservation

The copper nanoparticle-implanted nanocellulose (Cu@NC) fibrils and honey (Hon)-incorporated chitosan/polyvinyl alcohol (CS/PVA) matrix-based nanocomposite films were fabricated for food packaging applications. Self-synthesized Cu@NC was used as a nanofiller that fortifies the food packaging film, following a “hit two targets with one arrow” approach. The effects of Cu@NC and honey on various properties were investigated. The composite film exhibited exceptional UV barrier properties (up to 500 nm), enhanced hydrophobicity (86 ± 1.1°), extended lifespan, and biodegradability, indicating it as a “low-impact” material. Notably, the tensile strength of the nanocomposite film enhanced to 4.63 ± 0.04 MPa, water vapor transmission reduced to 55.68 ± 0.69 gm⁻² h⁻¹, and the solubility decreased to 65.72 ± 0.83% upon adding Cu@NC, making the films more effective for food preservation. The nanocomposite film exhibited strong antimicrobial activity against Gram-positive bacteria, Staphylococcus aureus (MRSA), Gram-negative bacteria, Escherichia coli, and the fungal strain, Candida albicans. The overall migration values of Cu@NC2 in different simulants were lower than the permissible limit (10 mg/dm²). When applied to strawberries, the films significantly minimized weight loss and prevented microbial contamination under storage conditions (25 °C and 50 ± 5% RH). With their superior mechanical properties, antimicrobial efficacy, and flexibility, the Cu@NC and Hon-infused CS/PVA films are promising for fruit storage and transportation.