Optimization of oat protein and gum Arabic microcapsules containing juniper essential oil using Response Surface Methodology

Abstract

In this study, we explored the feasibility of using oat soluble protein and gum Arabic as wall materials for microencapsulation via complex coacervation of juniper dissolved in wheat germ oil EO. The process was optimized using Response Surface Methodology (RSM), varying mixing ratios (20–80%) and pH levels (2−6), followed by freeze-drying of the coacervates. Physicochemical properties of the resulting powders, including solubility, hygroscopicity, moisture content, color, particle size distribution, and bulk and tapped density, were assessed. Encapsulation efficiency (EE) was determined through surface and total oil content calculations, supported by FT-IR spectroscopy. Characterization involved e-nose sensor analysis and differential scanning calorimetry (DSC). The study findings revealed encapsulation efficiencies (EE) ranging from 23.38 % to 26.58%, accompanied by low bulk and tapped densities (0.11–0.17 g/cm3 and 0.20–0.28 g/cm3, respectively), as well as elevated Carr Index values (36.92–46.34) and Hausner ratios (1.59–1.86). Moisture content varied between 0.07 % and 0.93 % across the samples. Additionally, the research demonstrated that employing oat protein and gum Arabic as wall materials enables the production of microcapsules with thermal stability exceeding 100 ℃, facilitating their potential application in the food industry.