Influence of free and microencapsulated oregano oil on starch and poly (butylene co-terephthalate adipate) active film properties

The objective of this work was to produce thermoplastic starch (TPS) and poly (butylene co-terephthalate adipate) (PBAT) incorporated with free and microencapsulated oregano essential oil (OEO) by blown extrusion and compare their properties. The OEO was microencapsulated by spray drying using arabic gum and maltodextrin as wall materials. The films were characterized in terms of physical, optical, morphological, thermal and antioxidant properties, and the OEO diffusion coefficient was determined in different food simulants. Regarding water vapor permeability (2.04–2.05 × 10−7 g m−1 Pa−1 h−1) and water solubility (6.25–9.65%), no significant difference (p > 0.05) was observed. Morphological images revealed that films with OEO microparticles (FM) showed greater roughness that caused a reduction in tensile strength, Young's modulus and elongation. FM film showed better thermal stability, significant concentration of phenolic compounds (3.6 mg EGA gfilm−1) and antioxidant capacity, and higher diffusion coefficient in ethanol 10% (aqueous food simulant, 1.3109 × 10–11 cm2 s−1) and 95% (non-aqueous food simulant, 39.8623 × 10–11 cm2 s−1). The results demonstrate the use potential of microencapsulated OEO in the development of biodegradable antioxidant films for food applications.