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

In this study, it is aimed to encapsulate some functional components of the olive leaves which not used industrially yet and considered to be a by-product or residue. In this study of thesis; olive leaf exract was encapsulated using solution of sodium alginate (2% w/v), sodium alginate (2% w/v)/gelatin (5% w/v) and sodium alginate (2% w/v)/agar (1.5% w/v) as wall material by ionic gelation/extrusion technique. In same study olive leaf extract was encapsulated using solution of gelatin (5% w/v) as wall material by gelation/emulsion technique. The flow behaviors and viscosities of the coating materials used in the thesis were investigated; the optimization process was performed in order to determine the flow rate and injection time to be applied in the ionic gealtion process and the encapsulation efficiencies, particle sizes, swelling rates, in vitro release profiles and antioxidant capacities of the obtained capsules were determined. It was found that flow behavior of gelatin and sodium alginate/gelatin materials were newtonian, flow behavior of sodium alginate material was pseudoplastic, flow behavior of sodium alginate/agar material was Herschel-Bulkley at 25 °C in the shear rate range of 1 – 100 s-1. As a result of the optimization was done for the purpose of determining the flow rate and injection time, the highest encapsulation efficiency was found when the flow rate of 2 mL/min. and 2 min. injection time (52.2±2.01%) were applied. It was determined that the encapsulation efficiency of the capsules obtained using gelation coating solution by gelation technique was 98.2±0.99%. Encapsulation efficiencies of sodium alginate, sodium alginate/gelatin and sodium alginate/agar coating solutions used in encapsulation by ionic gelation technique were determined as 48.71±1.26%, 61.54±0.95%, 55.7±0.60% respectively. It was determined that the particle size of the capsules obtained using gelation coating solution by gelation method was 1.31±0.25 mm3. Particle sizes of capsules obtained using sodium alginate, sodium alginate/gelatin and sodium alginate/agar coating solutions used in encapsulation by ionic gelation, were determined as 0.58±0.16 mm3, 1.39±0.35 mm3, 0.75±0.22 mm3 respectively. The highest swelling rate and the highest release rate in pH 1.1/pH 7.4 was obtained using the gelatin as coating solution by the gelation technique. The correlation were found between antioxidant activities and the encapsulation efficiencies of the capsules. In this study; it has been found that the encapsulation of olive leaf extract using ionic gelation and gelation techniques, will contribute to increase the stability and bioavability of the pheonolic compounds.