Preparation and evaluation of w/o/w-type emulsions for encapsulation of citronella essential oil by inverse ionic gelation

Citronella (Cymbopogon winterianus) essential oil (EO) has a significant commercial interest. Encapsulation is crucial to maintaining EO characteristics and stability. Herein, the impact of different emulsions on the encapsulation of citronella EO by inverse ionic gelation is evaluated. The variables studied include the concentration of CaCl2 (4-12%), the addition of corn starch (0.5%) to the emulsion, and the concentration of sodium alginate solution (0.5% and 1%) in the gelling solution. Emulsions and capsules were characterized through several techniques. Complex water/oil/water (w/o/w) emulsion showed stability for only 5 min after formation. Emulsions with different concentrations of CaCl2 showed no difference in viscosity, but there was a significant effect in the alginate bath. Six proposed formulations formed intact capsules. Adding Tween 80 to the alginate bath reduced the surface tension, producing more spherical capsules. Corn starch impacted the crosslinking of the alginate with CaCl2, resulting in thicker layers with fewer cracks.