Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Schematic illustration of the valorization of peanut skin waste into antioxidant polycaprolactone films and their migration behavior for reusable active food packaging.

ABSTRACT
Biodegradable polycaprolactone (PCL) films were developed with 13% w/w ethanol extract from industrial peanut skin residues (PSE), a rich source of natural antioxidants and antimicrobials. Films retain actives during processing. Antioxidant activity was evaluated via total phenolics, flavonoids, condensed tannins, and radical scavenging assays (DPPH, ABTS). PSE incorporation enhances oxidative thermal stability, increasing oxidation onset temperature (OOT) by 61°C—eliminating the early oxidative stage of neat PCL—and extending oxidation induction time (OIT), without compromising suitability for food packaging. Oxidative stability is maintained after accelerated storage (90 days at 40°C) and repeated migration tests simulating contact with refrigerated fatty foods. Migration assays confirm effective release of actives under repeated use. Mass transfer parameters were obtained by fitting experimental data to Fick's second law and the Arrhenius model, yielding intrinsic diffusion coefficients in 95% ethanol from 5°C to 40°C (4.17 × 10−15–7.1 × 10−14 m2·s−1), eliminating swelling at 40°C. Coefficients fall within typical polymer–antioxidant ranges, reflecting strong retention and controlled release due to the PCL matrix and complex PSE mixture. Overall, the films demonstrate long-term chemical and functional stability, enhanced thermo-oxidative resistance, and controlled antioxidant release, supporting their application in refrigerated, lipid-rich foods within a circular economy framework.