Influence of essential oil: cyclodextrin ratio and stirring rate on physicochemical characteristics of orange essential oil: β-cyclodextrin microparticles

Some encapsulation process and formulation parameters influence on several physicochemical properties of the encapsulated products. In this study, the influence of the OEO:β-CD ratio and stirring speed on the total oil, surface oil, oil retention, entrapment efficiency, yield, size distribution (d10, d32, and d43), span value, bounding rectangle aspect ratio (BRAR), Feret’s aspect ratio (FAR), circularity, smoothness, and opacity of microparticles were examined. The superior entrapment efficiency (95.18%), highest oil retention (79.13%), and lowest surface oil content (10.02 mg oil/g powder microparticles) were achieved at an OEO:β-CD ratio of 0.15 (w/w) and stirring speed of 700 rpm. Likewise, all microparticles showed irregular and elongated shapes, in which the opacity distribution was more influenced. Finally, the obtained FTIR spectra contained OEO bands hidden inside β-CD peaks, indicating the occurrence of a complexation reaction after encapsulation.