Improved Edible Films for Food Packaging: Optimization of Blends Based on Tapioca Starch, Gelatin, and Whey Protein Concentrate

The food industry is increasingly exploring biodegradable and edible packaging as alternatives to synthetic polymers. This study evaluated edible films made from tapioca starch (TS) blended with porcine gelatin (PG) or whey protein concentrate (WPC), focusing on how different TS:PG and TS:WPC ratios (80:20, 70:30, 60:40 w/w) and glycerol concentrations (2–3%) affect water vapor permeability (WVP), solubility, contact angle, opacity, and surface morphology. TS:PG films showed lower WVP (2.0–4.0 × 10–9 g·s–1·m–1·Pa–1), higher hydrophobicity (contact angle up to 119.28°), and smoother surfaces than TS:WPC films, which were more water-soluble (up to 35.29%) and porous. The optimal formulation─TS:PG at 70:30 with 2% glycerol─exhibited low permeability, high transparency (opacity < 1 mm–1), moderate solubility (21.20%), and hydrophobicity comparable to polyethylene. These results suggest that adjusting TS:protein and glycerol ratios can effectively tailor film properties, with TS:PG blends offering strong potential for sustainable food packaging.