Lignin-stabilized silver nanoparticles for fruit packaging: Synergistic antibacterial activity and tailored gas permeability.

Abstract

Fruit packaging is critical for maintaining safety and freshness, yet conventional petroleum-based materials lack controlled gas permeability and antibacterial functionality, severely limiting shelf-life extension. Current strategies use electrospun nanofibers loaded with silver nanoparticles (Ag NPs) to confer breathability and antibacterial activity; however, the agglomeration and instability of Ag NPs impede practical applications. Herein, we use sodium lignosulfonate (SL) to reduce and stabilize Ag NPs, then blend them with polyvinyl alcohol (PVA) and fabricate breathable, antibacterial packaging membrane via electrospinning. Benefiting from the electrostatic repulsion and steric hindrance provided by SL, Ag NPs exhibit excellent dispersion and stability within PVA nanofibers, as revealed by morphological analysis. Additionally, modulating Ag NPs concentration regulates PVA nanofiber diameter (252.8-132.1 nm), thereby tailoring pore structure and gas permeability. The obtained packaging membrane exhibits porosity (90.94%), suitable air permeability (∼41.4 mm/s), robust mechanical strength (∼22.1 MPa), excellent antioxidant capacity (DPPH scavenging ability, ∼64.3%), and effective antibacterial activity (inhibition zone of ∼10.4 mm, antibacterial rate ∼99.42%). Notably, in practical fruit preservation tests, this packaging membrane extends the shelf life of apples and strawberries by more than 4 days. This breathable and antibacterial packaging membrane presents a sustainable solution for reducing global fruit waste.