β-Cyclodextrin/tea saponin complex-stabilized eugenol emulsion functionalized composite films with antibacterial and sustained-release properties for fruit preservation.

Addressing the severe postharvest losses of perishable fruits and environmental concerns caused by plastic packaging, this study developed a multifunctional composite film. Specifically, a composite of β-cyclodextrin and tea saponin-a byproduct of camellia oil processing-was synthesized and served as a stabilizer for the eugenol emulsion. This composite exhibited favorable surface activity, endowing the emulsion with excellent storage stability. Further, incorporating the emulsion into a κ-carrageenan/cationic guar gum film-forming matrix, the obtained film exhibited favorable mechanical properties (tensile strength: 22.62 MPa, elongation at break: 33.16%), outstanding antioxidant activity (scavenging rates of 60.77% for DPPH and 94.03% for ABTS radicals), and excellent sustained-release effect. Strawberry preservation experiment further confirmed that the composite film can inhibit microbial growth and reduce water loss, thereby extending the shelf life of fruits. This study provides valuable insights for advancing green packaging technologies and promoting the sustainable utilization of food processing byproducts.