Development of bio-based nanoemulsion and pickering emulsion systems of eucalyptus essential oil stabilized by Persian Gum–HPMC–chitosan biopolymers: Toward industrial applications in functional films and sustainable biomaterials
Mahnaz Sheikhi, Roya Moghimi, Freshteh Rezazadeh
Abstract
Various biopolymers, including Persian gum (PG), hydroxypropyl methylcellulose (HPMC), and chitosan (CS), were combined to develop a novel edible biocomposite films. Two types of emulsions—nanoemulsion (NE) and Pickering emulsion (PE)—were formulated using Eucalyptus globulus essential oil (EO) and incorporated into the PG-HPMC-CS matrix. The evaluation and comparison of the physicochemical properties and antibacterial activities of both emulsions were evaluated and compared with those of pure EO. Additionally, the physical, mechanical, and antibacterial properties of the control edible film (QC-ED), NE-based film (NE-ED), and PE-based film (PE-ED) were assessed. The results revealed that in most cases, emulsification enhanced the antibacterial activity compared to pure EO. The addition of the emulsions did not significantly affect film thickness, water solubility, or water vapor permeability (WVP). However, it increased the swelling index and opacity while reducing tensile strength (TS) and elongation at break (EB). X-ray diffraction (XRD) revealed structural stability of the composite matrix following emulsion incorporation. Furthermore, the thermal stability and water contact angle of NE-ED and PE-ED films were considerably improved. The inhibition zones against S. aureus were 15 ± 2.5 mm for NE-ED and 13 ± 1.5 mm for PE-ED. These findings suggest the potential of eucalyptus-based NE and PE biocomposites for various applications in the food, pharmacy, and agriculture industry.