Electrospun fiber films based on high-stability HKUST-1@alkaline lignin composite carriers: pH controlled-release mechanism and antibacterial preservation applications

To address the challenge of short shelf life and microbial contamination in food preservation, this study aims to develop an intelligent pH-responsive antibacterial fiber film with controlled release capability. The modification of alkaline lignin improved the structural stability and specific surface area of HKUST-1 (from 547 to 1483 m 2 /g), while the composite film exhibited excellent mechanical properties (tensile strength: 3.74 MPa, elongation: 96.25%) and hydrophobicity (water contact angle: 120.55°). The film exhibited strong pH-dependent controlled release, with 81% of antibacterial agents released at pH 6.0 within 120 h. In vitro antibacterial tests demonstrated broad-spectrum activity against Escherichia coli ( E. coli ), Staphylococcus aureus ( S. aureus ), and Pseudomonas aeruginosa ( P. aeruginosa ). When applied to beef preservation, the film significantly reduced total volatile basic nitrogen (15.35 mg/100 g), total viable count (6.23 log CFU/g), and pH (6.02) after 9 days of storage, extending the shelf life by 4 days compared to the control. This work provides a feasible strategy for developing intelligent pH-controlled-release antibacterial packaging materials.