High-barrier and antioxidant lignin-reinforced starch nanofiber films for fruit preservation

Although conventional plastic packaging films offer practical benefits, their production contributes to fossil resource depletion and environmental pollution. In this study, formic acid facilitated the homogeneous dispersion of lignin and starch by protonating their polar functional groups. During electrospinning, rapid solvent evaporation induced the reformation of intermolecular hydrogen bonds and π-π interactions, resulting in a robust nanofibrous network. The synergistic interplay between the rigid aromatic structure of lignin and the chain entanglement capability of starch significantly enhanced the structural integrity and mechanical stability of the fibers. The resulting lignin-starch nanofiber films (LSNFs) function as multifunctional preservation materials with gas barrier, antibacterial, and antioxidant properties. The LSNFs exhibited a tensile strength of 13.55 MPa and a Young's modulus of 187.11 MPa. In addition, water vapor permeability and oxygen transmission rate decreased by 28.59% and 9.91%, respectively. The films also showed strong antioxidant capacity (89.53% DPPH scavenging), significant antibacterial activity, and hydrophobicity (water contact angle of 132.5°). Preservation tests demonstrated that LSNFs extended the shelf life of cherry tomatoes to 1.5 times that of the control, indicating their potential as sustainable alternatives to conventional plastic packaging.