Abstract
Potato-starch films containing raw papaya powder (RPP) and orange peel powder (OPP) were prepared by solution casting using glycerol as a plasticizer. Four formulations were evaluated: a potato-starch control (S1) and three composite films containing RPP and OPP at ratios of 70:30 (S2), 30:70 (S3), and 50:50 (S4). The films were characterized for mechanical, water-related, optical, spectroscopic, morphological, antioxidant, and soil-burial properties. S1 had the highest tensile strength (8.32 ± 0.40 MPa), elongation at break (10.81 ± 0.90%), and puncture resistance (0.70 ± 0.14 MPa), together with the lowest water vapor permeability (3.33 ± 0.15 × 10⁻⁹ g m⁻¹ h⁻¹ Pa⁻¹). The incorporation of the fruit powders reduced mechanical resistance and increased water vapor permeability. S3 had the highest water solubility (42.05 ± 0.08%) and water vapor permeability (4.50 ± 0.20 × 10⁻⁹ g m⁻¹ h⁻¹ Pa⁻¹), whereas S4 had the highest DPPH radical-scavenging activity (29.27 ± 0.15%). FTIR spectra showed formulation-dependent differences in band position and intensity, and SEM images showed greater surface heterogeneity in the composite films. After 30 days of soil burial, mass loss was 58% for S1 and 40–47% for the composite films. The results demonstrate composition-dependent trade-offs among mechanical resistance, moisture-barrier performance, radical-scavenging activity, and soil-burial mass loss. Further structural, thermal, gas-barrier, migration, and packaged-food studies are required before a specific food-packaging application can be established.