Electrohydrodynamic atomization of Balangu (Lallemantia royleana) seed gum for the fast-release of Mentha longifolia L. essential oil: Characterization of nano-capsules and modeling the kinetics of release

The aim of this study is to optimize encapsulation of Mentha longifolia L. essential oil into Balangu (Lallemantia royleana) seed gum nano-capsules, to increase their utility as flavoring and bioactive agents in foods and beverages. Essential oil emulsions with Balangu seed gum (0.25 and 0.5% w/w) and various polyvinyl alcohol (PVA) concentrations (0.5, 1 and 2%) combined with Tween-20 (0.06, 0.08 and 0.1%) were electrosprayed. Increasing the concentration of PVA increased the emulsion viscosity and improved both loading capacity (77.56-84.68%) and encapsulation efficiency (81.54-87.82%) of the essential oil within the structure of the Balangu gum nano-capsules. Field emission scanning electron microscopy (FESEM) indicated that by increasing the amount of the gum (from 0.25 to 0.5%) and PVA (from 1 to 2%), the process could be made to produce nanofibers. The Mentha longifolia L. essential oil was entrapped in nanostructures without any chemical interaction with encapsulant material; this was demonstrated by Fourier transform infrared spectroscopy and differential scanning calorimeter. The release mechanisms and kinetics of loaded Mentha longifolia L. essential oil were evaluated in different simulated food models (aqueous, acidic, alcoholic or alkalic and oily food models) and release profiles data were fitted to first order, Kopcha, Korsmeyer-Peppas, and Peppas-Sahlin models. The essential oil release profiles fitted well to the Peppas-Sahlin model for a range of simulated foods. The release mechanism of the essential oil from the nanostructure of the Balangu seed gum is mainly controlled by the Fickian diffusion phenomenon.