Sustainable ethyl cellulose fibrous films with nitrogen-carbon dots for fresh-cut apple preservation

Sustainable active packaging films are increasingly being explored as practical tools for prolonging the freshness of sliced fruits. This study reports the fabrication of ethyl cellulose/poly(ethylene oxide) fibrous films incorporated with nitrogen‑carbon dots (NCDs) using a simple electrospinning technique for active food packaging applications. The NCDs were prepared via a one-pot hydrothermal method using neem leaves as the precursor. As confirmed by HR-TEM, the synthesized NCDs had a quasi-spherical shape with a diameter of ~1.6 to 3.4 nm. In addition, the NCDs incorporated fibrous films exhibited excellent water stability, hydrophobicity, and mechanical properties. The fibrous films were examined to determine the UV-Vis resistance and free radical scavenging activity via DPPH and ABTS assays. At the higher concentrations of NCDs in the fibrous films, UV blocking of 99.9% against both UV-A and UV-B radiations was achieved, indicating their excellent UV resistance. Also, the DPPH and ABTS free radical scavenging rates remarkably raised to ~73% and ~90%, respectively. The visual decay and browning of fresh-cut apples packed in the fibrous films were reduced during the 5-day storage study. In conclusion, NCDs incorporated films could be utilized for an active, sustainable packaging material with enhanced UV resistance and antioxidant characteristics for preserving fresh-cut fruits.