Developing Active Bilayer Films Based on Poly(Lactic Acid) and Gelatin or Sodium Caseinate

ABSTRACT Bilayer films made from polymers with complementary properties, such as poly(lactic acid) (PLA) and proteins, loaded with active agents allow to produce materials with additional functionality compared to those used in conventional packaging. The objective of this research was the development of bilayer films based on PLA acting as the passive first layer, and gelatin or sodium caseinate films incorporated with Pickering emulsions (PE) encapsulating rutin and carvacrol acting as the active second layer. The bilayer films exhibited similar water vapor permeability (WVP) values, a reduction ( p < 0.05) in oxygen permeability (OP) (decrease of ~85%), and a greater material elongation of 6.7% compared to the monolayer PLA film. The bilayer films with gelatin showed better barrier properties (WVP and OP) compared to those with sodium caseinate. This same behavior was observed in the seal strength of the bilayer films with gelatin. Overall, the integration of PE in the bilayer films decreased the WVP by 11.5% ( p < 0.05) and the OP by 12.6% ( p < 0.05 for SC bilayer films), reduced in 50 to 81% the seal strength ( p < 0.05), provided notable ( p < 0.05) antioxidant action primarily in fatty food simulants, and exhibited antimicrobial activity against Escherichia coli . The bilayer films based on PLA‐protein activated with rutin and carvacrol in Pickering emulsion represent a promising material for future packaging that allows for a reduction in food deterioration processes.