Abstract:
Lemongrass (Cymbopogon ciatrus) is widely used as a herb in Thai cuisine for a long time. Nowadays, the lemongrass oil has been applied and used as a medicine due to citral, major component, has a reported antimicrobial activity. But citral had limited biological properties by oxidation of heat, light and oxygen. Therefore, encapsulation process is the way for enhancing their stability and releasing control. In this study, encapsulation of lemongrass oil with cyclodextrins (CD) was investigated by spray drying. The effect of type of cyclodextrin and the citral:CD molar ratio on total oil retention were studied during spray drying process. The results showed that β-CD and α-CD demonstrate the best encapsulation efficiency of E-citral and Z-citral, respectively, all of them showed the maximum total citral retention at the citral:CDs molar ratio 1:1. The morphology of powders appeared spherical shape with roughness for α-CD and γ-CD whereas β-CD presented crystallite. In addition, maltodextrin was added in inclusion complexes for helpful encapsulation efficiency. The results showed that the total oil retention was not increased with increasing MD. Furthermore, the release characteristics of spray dried powders were studied. The results suggest that β- CD complex had a lower releases rate than those for γ-CD complex and α-CD complex. The release of included citral in the complexes corresponded to the limited diffusion kinetics system.