Edible Films Based on Corn Starch and Gelatin Obtained by the Combination of Extrusion and Casting Process: Characterization and Applications

The development of edible films (EFs) using renewable resources such as gelatin and native corn starch has garnered significant interest due to their potential to enhance food preservation and safety. Combining extrusion with the casting method enhances mechanical and barrier properties by modifying starch and gelatin structures through heat, pressure, and shear. This study aimed to develop, characterize, and optimize the functional properties EFs produced from an extruded formulation of corn starch, gelatin, and glycerol using the casting method. Furthermore, it evaluated the impact of these optimized EFs as coatings on the quality characteristics of the “Kent” mango cultivar. The study factors were gelatin content (GC, 0–10%) and extrusion temperature (ET, 80–120°C). The EFs were characterized and optimized, determining the tensile strength (σ), elongation (ε), water vapor permeability (WVP), and Water Solubility (S), using the surface response methodology. Results showed GC significantly influenced mechanical and barrier properties (P < 0.05), with higher GC increasing σ, ε, WVP, and S. ET also affected mechanical properties (P < 0.05) but not barrier properties (P > 0.05). EFs exhibited σ of 3.14 MPa to 8.34 MPa, ε of 10.55–25.60%, WVP (5.59 × 10^–12 to 6.82 × 10^–11 g m Pa^-1 s^-1 m^-2), and S from 66.29–80.50%. According to the optimization study, the EFs with the best mechanical and barrier properties were obtained using an ET of 80°C and GC of 2.93%. Applied as coatings on ‘Kent’ mango, these EFs significantly extended shelf life and preserved postharvest quality.