Preparation of cellulose acetate-based active films containing oregano essential oil and sodium alginate for food packaging
Abstract
This study developed and evaluated cellulose acetate (CA)-based films incorporating oregano essential oil (OEO) and sodium alginate (SA) for application as active food packaging. OEO, a natural plant extract with known antimicrobial and antioxidant properties, was emulsified by combining oil and water phases to form a stable mixture, which was then added dropwise into the CA gel before film formation. Films were produced using the casting method and investigated for antioxidant and antimicrobial activities, water vapor barrier properties, infrared spectra (IR), thermal behavior, and morphological characteristics. Antioxidant activity was quantified using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, which demonstrated a concentration-dependent increase in radical scavenging, with the CA/SA/OEO 4.5% film achieving 84% activity. Antimicrobial assays, which test a material's ability to inhibit the growth of bacteria, indicated inhibition zones of 35 mm against Escherichia coli and 44 mm against Staphylococcus aureus . Scanning electron microscopy (SEM) analysis showed that uniform dispersion of emulsion droplets improved film structure and enhanced barrier properties. These findings indicate that CA-based films containing oregano essential oils are promising biodegradable and multifunctional materials for active food packaging.