Microencapsulation of agarwood (Aquilaria crassna) essential oil by spray drying

Abstract Agarwood essential oil is the essential oil extracted from the heartwood of agarwood trees (Aquilaria sp.) after inoculation or natural infection of one of several fungal species. The essential oil is proved to carry antioxidant, antimicrobial and anti-stress activities. Microencapsulation of essential oil included emulsification of oil into maltodextrin solution and spray drying of emulsion at different levels of inlet temperature and compressed air pressure. Microencapsulation process was qualified based on following parameters including process’s microencapsulation yield, moisture content of powder, powder particle size, encapsulated oil’s composition, oil recovery and drying yield. Microencapsulation yield was affected by inlet temperature whereas drying yield changed as air pressure varied from 1.5 to 2.5 kgf/cm2. Other parameters were impacted by both variables. Besides, oil composition changed at an acceptable degree after microencapsulation process, in which there were an increase in percentage and the presence of some components but the main components still remained in the encapsulated oil. Finally, the drying air temperature of 150 °C and air pressure of 2.5 kgf/cm2 were the best parameters to obtain both microencapsulation yield of 89.12% and drying yield of 79.00%.