Development of active films poly (butylene adipate co-terephthalate) - PBAT incorporated with oregano essential oil and application in fish fillet preservation

The food industry has been using antimicrobial active packaging as a tool for maintaining the quality of highly perishable products such as fish products. The use of synthetic materials, though, causes serious environmental impacts due to inappropriate disposal. Therefore, eco-friendly polymer materials from renewable sources stand out as alternatives to reduce such impacts. This study set out to develop biodegradable antimicrobial films comprising poly(butylene adipate-co-terephthalate) (PBAT) and oregano (Origanum vulgare) essential oil (OEO) for application in fish fillet storage. Films were produced by hot-melt extrusion and characterized as to morphological, mechanical, physical, water barrier, and structural properties. Their bioactive, antioxidant, and antimicrobial activities were also analyzed. OEO incorporation did not affect films' thermal properties, but the mechanical attributes tensile strength, elongation at break, and elastic modulus were impaired. Scanning electron microscopy images indicated heterogeneous, rough surfaces and cross-sections upon OEO addition. The higher the OEO content, the greater the water vapor permeability. Fourier-transform infrared spectroscopy corroborated the presence of OEO bioactive compounds in the extruded films. Microbiological assays demonstrated the effectiveness of the films in lessening total coliforms, Staphylococcus aureus and psychrotrophic microorganisms.. Concerning antioxidant properties, the higher the OEO concentration, the stronger the antioxidant activity. The films produced here were found to be efficient as an active packaging system to control microbial growth in fish fillets. Additionally, their mechanical, thermal, and water barrier properties were demonstrated to be suitable for food packaging applications.