Development and characterization of sodium alginate/tea tree essential oil nanoemulsion active film containing TiO2 nanoparticles for banana packaging

To improve the postharvest quality and reduce the anthracnose of bananas, the sodium alginate (SA)/tea tree essential oil nanoemulsion (TEON) based bilayer films incorporated with different contents of TiO2 nanoparticles were fabricated in this work. The developed TEON presented satisfactory DPPH scavenging activity (65.5 ± 1.8%) and antifungal capability (90.5 ± 5.8%). The microscopy images of the cross-section of the films indicated that the bilayer films with well-cross-linked were developed successfully. Notably, the addition of a certain content of TiO2 to SA greatly improved the UV blocking and water vapor and oxygen barrier properties of the developed film. However, the barrier property of the film was decreased when the TiO2 content further increased to 4.0 mg/100 mg of SA. The retention of TEO under visible and UV light in the bilayer film was respectively prolonged to 24 days and 32 h when the addition of TiO2 content was 2.0 mg/100 mg of SA. Finally, the postharvest quality and anthracnose of banana fruits were significantly improved by SA-TiO2 + SA-TEON film-forming solution treatments. Results from the present work might open up new insights into the approaches of postharvest quality improvement of bananas.