Correlating the pre–emulsion conditions of film–making with the characteristics of active chitosan films containing orange essential oil (Citrus sinensis L.)

Film–making–pre–emulsions (FMPs) based on chitosan alone or in combination with orange essential oil (OEO) were produced under various emulsification treatments (Ultra–emulsification (UE) or UE together with sono–emulsification (SE) at different times (1, 3, and 5 min)). The UE/SE FMPs containing OEO demonstrated different characteristics. Both the size distribution and the ζ–potential of the FMPs decreased, while the Coulombic interactions improved by applying SE–1 and SE–3. Based on the atomic force microscopy test, SE–1/SE–3 resulted in a decrease in migration of the FMPs. According to our data, the average roughness of the 0.50 % OEO–SE–3 film was 12.15 ± 2.23 nm, and SE–1/SE–3 had a release–controlling effect on OEO. As a result, the OEO–SE–3 loaded film showed poor biological activity against Escherichia coli (8.79 ± 1.38 mm). The films made from SE–1/SE–3 FMPs, exhibited higher density, water vapor resistance, and elasticity than the films casted from UE or SE–5.