Antioxidant and antibacterial PVA films containing lignocellulosic nanofibers and carbon dots from bamboo shoot shells treated with deep eutectic solvents

In this study, a stepwise deep eutectic solvent treatment strategy was developed to convert bamboo shoot shells into lignocellulosic nanofibers (LCNFs) and carbon dots (CDs) for the fabrication of multifunctional PVA–based active packaging films. LCNFs with a high aspect ratio of 565.5 were obtained through stepwise ZnCl 2 /LA–ChCl/CA/H₂O DES pretreatment, whereas CDs bearing abundant surface functional groups were produced by hydrothermal conversion of the recovered ZnCl 2 /LA liquor. The obtained LCNFs and CDs were co–incorporated into the PVA matrix to improve the antioxidant and antibacterial performance of the pristine PVA films. These nanofillers endowed the films with a uniform structure, favorable UV–shielding performance, high tensile strength of 75.4 MPa, enhanced thermal stability, improved water resistance, suitable water vapor permeability (3.55 × 10 –13 kg/m·Pa·s), good CO 2 /O 2 selectivity (8.4), as well as excellent radical–scavenging activity against DPPH and ABTS radicals and antibacterial activity against E. coli and S. aureus . In strawberry preservation tests, the composite film effectively retained the total soluble solids and bioactive compounds in strawberries and inhibited lipid peroxidation during storage. This work provides an integrated approach to lignocellulosic fraction valorization and a framework for multifunctional PVA-based active packaging containing biomass-derived nanofillers.