Active packaging film utilizing cerium metal-organic frameworks doped with titanium dioxide as ethylene scavengers for postharvest ripening control of avocados

Cerium-based metal-organic frameworks doped with titanium dioxide (TiO₂-MOFs) were synthesized and applied to control the postharvest ripening of avocados via ethylene scavenging. TiO₂-MOFs improved ethylene scavenging performance, completely removing 100 ppm of ethylene within 6 h of UV light exposure using 0.08 g of particles. TiO₂-MOFs were integrated into cellulose nanofiber (CNF) films to improve UV-blocking capacity with the transmittance at 280 nm decreasing to 1.54 %. Incorporation of 6 wt% TiO₂-MOFs improved the hydrophobicity of the film with an increase in the water contact angle of the CNF film from 45.23 ± 3.21° to 65.13 ± 5.11°. However, the mechanical strength slightly decreased due to particle aggregation. CNF/TiO₂-MOFs films effectively delayed avocado ripening, as evidenced by the reduced ethylene accumulation, slow color degradation, and low browning index. These results suggest that the CNF/TiO₂-MOFs films have strong potential for active packaging applications, especially useful for extending the shelf life of ethylene-sensitive avocados.