Development and application of poly(butylene adipate-coterephthalate) composite film with copper oxide nanoparticles for prevention of greening in potatoes

In this study, an eco-friendly packaging film was developed to inhibit light-induced greening in potatoes by incorporating various organic and inorganic fillers, such as copper oxide nanoparticles (CuONPs), zinc oxide nanoparticles, zinc basic salts, microcrystalline cellulose, nanocrystalline cellulose, and calcium–iron layered double hydroxides, into poly(butylene adipate-co-terephthalate) (PBAT) via solvent casting. Among these fillers, the PBAT film with CuONPs exhibited the lowest UV-visible light transmittance, especially at 450 nm, and was selected for further study. Three potato cultivars commonly distributed for processing in Korea (Superior, Duback, and Eunsun) were packaged with the CuONPs composite films. Neat PBAT film, commercial HDPE film, and unpackaged samples were used as controls. After 6 days of fluorescent light exposure, the CuONPs composite film significantly reduced color change (ΔE=7) in Duback and Eunsun, indicating effective greening inhibition. SEM and XRD analyses confirmed uniform CuONPs dispersion without altering PBAT crystallinity. FT-IR spectra revealed no chemical interaction, indicating physical incorporation. Mechanical testing showed no significant difference in tensile strength, elongation, or elastic modulus compared to neat PBAT, with tensile strength values comparable to those of commercial LDPE. The CuONPs composite film also exhibited favorable water vapor permeability (5.83×10−10 g · m/m2 · Pa · s), supporting its potential as a functional packaging material for light-sensitive produce like potatoes.