Investigation of the effects of some wall materials and encapsulation techniques on the microencapsulation of olive leaf extract

Abstract

In this study, it is aimed to encapsulate some functional components of the olive leaves. Olive leaf extract was encapsulated using solution of sodium alginate, sodium alginate/gelatine, and sodium alginate/agar as wall material by ionic gelation technique. Also, olive leaf extract was encapsulated using solution of gelatine as wall material by cold gelation technique. The viscosities of the coating materials used in the study were investigated. An optimisation process was carried out to determine the injection time to be applied in the ionic gelation technique and the encapsulation efficiencies, particle sizes, swelling ratios, in vitro release profiles, and antioxidant activities of the obtained capsules were determined. While the encapsulation efficiency of the capsules obtained by the cold gelation technique was determined as the highest (98.2 +/- 0.99%), it was revealed that the viscosity of the wall material used in the ionic gelation technique was important in the encapsulation efficiency. The particle size and swelling rate of the capsules obtained using the cold gelation technique were the highest. The release rate of oleuropein was generally higher at gastric pH than at intestinal pH. A correlation was found between antioxidant activities and the encapsulation efficiency of capsules.