Improvement of the physicochemical and mechanical properties of intelligent gelatin/butterfly pea films using coconut milk residue

• CRPC incorporation enhanced film flexibility while reducing tensile strength and solubility. • Films exhibited pH-indicating performance via color changes in alkaline gas exposure. • Films with 3% CRPC showed the most significant changes in mechanical and optical properties. This research investigated the effects of coconut milk residue protein concentrate (CRPC) incorporation (0-3% w/w) on the properties of gelatin-based films containing butterfly pea extract. The films were characterized by their physiochemical, mechanical, and gas-sensitivity properties. The addition of CRPC significantly influenced film properties, demonstrating decreased tensile strength (22.47 to 16.94 MPa) and solubility (29.54 to 24.34%) while increasing elongation at break (42.05 to 53.51 %) ( p < 0.05). Water vapor permeability showed no significant differences among treatments. Colorimetric analysis of alkaline gas sensitivity demonstrated consistent color transitions from blue to green across all formulations upon exposure to ammonia. The molecular interactions between CRPC and gelatin proteins resulted in a modified film structure, affecting physiochemical, mechanical and optical properties. These findings suggest that CRPC incorporation can effectively modify film properties while maintaining gas-indicating functionality, offering potential applications in intelligent food packaging systems. The developed films demonstrate promise as biodegradable alternatives for smart packaging applications, effectively combining mechanical stability with gas-sensing capabilities.