Determination of the Optimum Conditions for Emulsification and Encapsulation of Echium Oil by Response Surface Methodology

Echium oil (EO) contains substantial amounts of omega-3 fatty acids, which are important because of their benefits to human health. However, they are prone to oxidation. The aim of this study was to obtain the optimum conditions of microencapsulation of EO using spray drying by applying the response surface methodology (RSM). Central composite circumscribed design (CCC) was employed with a ratio of maltodextrin (MD):EmCap modified starch (MS) (80-90%, w/w), oil concentration (15-25%, w/w), and homogenization speed (5-15 × 10³ rpm) as independent variables affecting droplet size (μm) and viscosity (Pa·s), which were chosen as responses for the emulsification process. The results revealed that the emulsion conditions containing MD:MS (89.7%:10.3%, w/w), oil concentration of (16.0%), and homogenization speed at (14.8 × 10³ rpm) were found to be the optimum conditions. Furthermore, for encapsulation, CCC was employed with inlet temperature of 140-180 °C, air flow of 20-30%, and pump rates of 15-25% as independent variables. Total yield (%) and encapsulation efficiency (%) were chosen as responses for the encapsulation process. On the other hand, optimum conditions for encapsulation were as follows: inlet temperature of 140 °C, airflow rate of (30%) 0.439 m³/h, pump rate of (15%) 4.5 mL/min with respect to selected responses.