Preparation of Chitosan Microcapsules Containing Red Ginger Oleoresin Using Emulsion Crosslinking Method

Abstract

Background: Encapsulation is one of the methods used to trap active ingredients in the wall material of microparticles. Aim: The aim of this study was to evaluate the encapsulation of red ginger oleoresin using an emulsion crosslinking method with chitosan as the wall material. Methods: Emulsions were formed of red ginger oleoresin with chitosan in concentrations of 1%, 2%, 3%, and 4% (w/v), respectively. The emulsions were then mixed with corn oil and stirred for one hour to obtain a second set of emulsions, and glutaraldehyde saturated toluene (GST) was added dropwise in quantities of 20, 10, 6.7, and 5 ml, respectively. This was followed by the addition of 2 ml of 25% glutaraldehyde and the emulsions were stirred for two hours. The resulting microcapsules were washed with petroleum ether followed by hexane and then dried in an oven at 70oC. Results: The emulsion crosslinking method used to trap the red ginger oleoresin in chitosan produced microcapsules of good spherical geometry with the mean diameter ranging from 75.61 ± 11.8 µm to 178.65 ± 40.7 µm. The highest yield was 98.93% and encapsulation efficiency was 83.1%. Thermogravimetric and differential thermal analysis showed that the melting point was at a temperature between 120 and 130oC. Conclusion: Chitosan concentration has little effect on encapsulation yield, whereas the amount of GST tends to strengthen the crosslinking bonds of chitosan and reduces the mean diameter of microspheres.