Compostable properties of antimicrobial bioplastics based on cinnamaldehyde cross-linked gliadins

Abstract

[EN] The disintegration, biodegradation and ecotoxicity of cross-linked wheat gliadin films with antimicrobial properties were assessed under controlled composting conditions. Gliadins were chemically modified with different percentages of cinnamaldehyde (1.5%, 3% and 5%) increasing their cross-linking degree and imparting antimicrobial activity. After the films were subjected to simulated conditions of use in a food packaging application, they were composted. The most cross-linked gliadin film showed a very fast disintegration profile. It completely disintegrated into fine visually indistinguishable residues after 4 days of being inserted in compost medium. Scanning electron microscopy revealed the rapid microbial colonization of the films' surface. Biodegradation was assessed by measuring the amount of carbon dioxide produced in a static system specifically designed for this study. The cross-linking degree of the protein-aceous matrices modified their biodegradation rate without impairing their complete biodegradation. The presence of residual cinnamaldehyde in the films, which can exert antimicrobial activity, did not hamper their biodegradation neither caused ecotoxicity on tomato seeds germination and plant growth. (C) 2014 Elsevier B.V. All rights reserved.