Visible light-induced antibacterial pea protein isolate/bacterial cellulose composite films incorporated with nitrogen-doped carbon dots for strawberry preservation.

Microbial contamination-induced food spoilage necessitates antibacterial packaging, with visible light-driven systems gaining attention due to their controllability and environmental compatibility. In this study, positively charged nitrogen-doped carbon dots (N-MCDs) were synthesized and incorporated into a pea protein isolate/bacterial cellulose (PPI/BC) matrix to fabricate biodegradable composite films (PPI/BC@N-MCDs) with antibacterial and antioxidant properties. N-MCDs imparted films with visible light-responsive antibacterial activity by generating reactive oxygen species under light irradiation, disrupting bacterial membranes. The composite films exhibited excellent antibacterial performance, with inhibition rates exceeding 99% against E. coli and S. aureus. Compared with pure PPI films, composite films showed enhanced mechanical properties, with tensile strength increasing from 2.00 MPa to 18.65 MPa. In addition, the films demonstrated improved barrier properties and reduced surface wettability. Preservation tests confirmed that the films effectively delayed quality deterioration and nutrient loss in strawberries. This study provides a viable strategy for developing sustainable, light-responsive antibacterial packaging materials.