Optimisation of microencapsulation of holy basil essential oil in gelatin by response surface methodology

To protect holy basil essential oil (HBEO) from volatilisation and oxidation, microencapsulation by simple coacervation of gelatin was developed. An optimal encapsulating condition obtained from response surface methodology (RSM) was a gelatin concentration of 11.75% (w/v) and an HBEO amount of 31 ml, which provided the greatest yield, oil content, and encapsulation efficiency of 98.80%, 66.50%, and 95.41%, respectively. Scanning electron microscope (SEM) revealed that the internal surface of the microcapsule was honeycomb-like networks containing nonhomogeneous distributions of HBEO. Fourier transform infrared spectroscopy (FTIR) indicated that there was no significant interaction between the HBEO and gelatin. Under storage conditions at 60 °C for 49 days equivalent to 25 °C for 18 months, small decreases in the HBEO retention rate and the antioxidant activity were observed. Thus, the microencapsulated formulation has potential to be applied to other volatile compounds.