Effect of secondary emulsion parameters on Gac oil encapsulation by gelatin in double emulsion

Gac oil was encapsulated in gelatin using the oil in water in oil (o/w/o) double emulsion method. The o/w single emulsion was formed by homogenizing Gac oil with gelatin solution and dispersing into liquid paraffin to form the o/w/o double emulsion. Microcapsules were stabilized by lowering the temperature of the double emulsion to a temperature below the gelatin’s gelation point. Effects of parameters, including temperature and stirring speed, on encapsulation yield, encapsulation efficiency and microcapsule size were investigated. The results show the highest encapsulation yield of 93.47 %, with encapsulation efficiency of 86.49 % and microcapsule size of 156 µm. The difference in temperature between single emulsion and paraffin reduced the encapsulation yield by 6.74-12.88 %. The size of microcapsules decreased as the temperature of single and double emulsions increased. Besides, increasing the stirring speed during the formation of the double emulsion reduced microcapsule size and encapsulation yield. Otherwise, the encapsulation yield was not affected by all investigated conditions. The microcapsules were spherical with size deviation. Microcapsules surface was continuous with irregularities or wrinkles.