Antibacterial and ultraviolet-shielding film based on chitosan quaternary ammonium salt, lignin, and nisin: preparation, characterization, and application

A novel HACC/lignin composite film incorporating nisin was successfully fabricated. • Lignin incorporation endows the film with superior ultraviolet-blocking capability. • The addition of nisin significantly improves the mechanical and barrier properties. • Nisin confers potent and broad-spectrum antibacterial activity to the composite film. • The film effectively extends grape shelf life by antibacterial and anti-UV functions. A multifunctional composite packaging film integrating chitosan quaternary ammonium salt (HACC), lignin, and nisin was developed to achieve synergistic UV-blocking and antibacterial performance. Nisin, uniformly dispersed throughout the HACC/lignin matrix via hydrogen bonding, not only imparted potent antibacterial activity but also reinforced mechanical strength, thermal stability, and barrier performance. Of all formulations evaluated, HLN-0.4 delivered the most favorable combination of properties: a tensile strength of 5.99 MPa, an elongation at break of 141.21%, and effective antibacterial activity against Staphylococcus aureus , Bacillus subtilis , and Listeria monocytogenes . In grape preservation trials, HLN-0.4 extended postharvest shelf life to 15 days, curtailed weight loss from 17.9% to 9.0%, and sustained fruit firmness at 29.74 N, approximately 63% above the 18.28 N measured in unpackaged controls. Taken together, these findings position HLN-0.4 as an effective, sustainable, and scalable packaging solution with strong potential for extending postharvest shelf life and maintaining the quality of fresh produce. Download: Download high-res image (306KB) Download: Download full-size image