A ROS-activating antibacterial and antioxidant polyurethane film based on chlorogenic acid for high-efficiency grape preservation

In the global food waste crisis, perishable fruits contribute significantly to global food losses. In this study, a novel PU-CA composite film was synthesized using Polycaprolactone triol (PCL) and isophorone diisocyanate (IPDI) as the matrix, with chlorogenic acid (CA) added. The mechanical properties, hydrophobicity, antibacterial activity, and antioxidant capacity of film were characterized. The results showed that when the CA content was 6 wt%, the elongation at break of the film reached 450.35 %, and its tensile strength increased by 173.96 % compared to pure PU film. The PU-CA composite film exhibited 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-Azano-bis (3-ethylbenzothiazo-line-6-sulfonic acid) diammonium salt (ABTS) radical scavenging rates of 86.73 % and 75.40 %, respectively. Meanwhile, it exhibited antibacterial activity against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ), as well as biocompatibility (cell viability >90 %). Further grape preservation tests confirmed that the PU-CA composite film can effectively reduce the weight loss rate of grapes from 14 % to 2 % over an 8-day storage period, thereby extending their shelf life. These findings suggest that PU-CA composite films have broad application prospects in grape preservation packaging.