Preparation, antioxidant and antibacterial properties of PCL/APS composite nanofiber films embedded with CS/TPP-CV nanospheres for blueberry preservation.

At present, active cling films for food preservation face a core bottleneck: the encapsulation materials for active substances have limited effectiveness, failing to achieve a balance between material safety and sustained-release performance. In this study, carvacrol (CV) was encapsulated in chitosan (CS)/sodium tripolyphosphate (TPP) ionic gelation nanospheres, with an encapsulation efficiency of 89.3 ± 1.1%. The gel nanospheres were integrated into polycaprolactone/astragalus polysaccharide (PCL/APS) nanofibers via electrospinning (ELS) technology to fabricate active cling films. Characterization results showed that increasing the chitosan/tripolyphosphate-carvacrol (CS/TPP-CV) loading enlarged the nanofiber diameter, reduced the water contact angle, and simultaneously increased the water vapor transmission rate. The packaging film exhibited significant antibacterial activity against Escherichia coli (96.5% inhibition rate) and Staphylococcus aureus (95.1% inhibition rate), along with excellent antioxidant capacity (DPPH radical scavenging rate of 60.2% and ABTS radical scavenging rate of 74.4%). In fruit preservation experiments, compared with the control group, the chitosan/tripolyphosphate-carvacrol-loaded nanofiber film reduced the weight loss of blueberries to approximately 3%, increased the retention of vitamin C (VC) content to around 40%, and extended the storage period of blueberries to 10 days. Blood compatibility tests confirmed that the material had an extremely low hemolysis rate, indicating high safety. This study pioneers the synergistic application of chitosan/tripolyphosphate gel nanosphere-encapsulated carvacrol and electrospun nanofibers, providing a scalable technical solution for next-generation food preservation.