An Antibacterial and Toughening Strategy Based on Carbonaceous Nano‐Lamellae Applying for Food Preservation

ABSTRACT Integrating walnut green husk‐derived carbonaceous nano‐lamellae (WCNL) into casein films (CF) addresses the challenge of combining mechanical strength, barrier performance, and antibacterial activity in sustainable food packaging. The hydrothermally synthesized WCNL features defect‐rich hierarchical networks that induces strong interfacial hydrogen bonding, creating a nano‐confined network, which dramatically improves mechanical strength (563% increase in tensile strength) and reduces water vapor permeability by 22.77% of CF‐WCNL, while offering excellent UV shielding and antioxidant activity. Standardized colony‐counting assays demonstrated antibacterial efficiencies approaching 100% against both E. coli and S. aureus under the tested conditions. Time‐kill kinetic analysis and live/dead fluorescence staining further reveal a pronounced time‐dependent loss of bacterial viability, supporting a bactericidal rather than merely bacteriostatic effect. It is posited that the antibacterial behavior may be comprised of multiple concurrent processes, including edge‐mediated membrane disruption, physical immobilization by the interconnected WCNL architecture, and ROS‐induced oxidative stress. This hypothesis is supported by bacterial morphological observations and ROS analyses. These findings demonstrate the potential of biomass‐derived carbonaceous nano‐lamellae for developing mechanically robust and multifunctional bio‐based food‐packaging films.