Microencapsulation of oils using sodium alginate

The feasibility of encapsulating wheatgerm oil and evening primrose oil using sodium alginate by the emulsification method was explored in this study. It is based on the chemical reaction between the water-soluble sodium alginate and polyvalent cation, calcium, to form the water-insoluble alginate. The factors investigated were the physical appearance of the microspheres, the amount of oil that could be encapsulated, the flow property, size distribution and mean size of the microspheres produced. Encapsulation efficiency and oil content of wheatgerm oil increased with an increase in oil load. The mean size of the microspheres increased sharply at a high oil load of 250% w/w. Photographs of microspheres taken showed that the microspheres were larger, spherical and had more vesicles within, as oil load increased. Encapsulation efficiency of evening primrose oil microspheres was similar to wheatgerm oil microspheres at the respective oil loads of 50, 250 and 350% w/w. The emulsification method developed was successfully applied to wheatgerm oil, a fixed oil, with a maximum encapsulation efficiency of approximately 88%. It was satisfactory for evening primrose oil, which also belongs to the family of fixed oils.