Evaluation of the microencapsulation of orange essential oil in biopolymers by using a spray-drying process

Essential oils are volatile compounds commonly used by several industries, easily degradable, which restrains their applications. Therefore, we developed and validated a methodology for producing microcapsules loaded with orange essential oil, using a spray-drying process. The experimental design results showed that the combination between a low flow transfer rate (0.15 L h^-1) of the colloidal suspension, a higher drying air flow rate (536 L h^-1), and an inlet air temperature of 150 °C to the spray-dryer were the most important parameters for the atomization efficiency. The method optimization resulted in microcapsules with powder recovery between 7.6 and 79.9% (w w^-1), oil content ranging from 8.9 to 90.4% (w w^-1), encapsulation efficiency between 5.7 and 97.0% (w w^-1), and particle sizes with a high frequency of distribution less than 4 μm. In these experiments, gelatin and lignin were evaluated as biopolymers of encapsulation. We also developed an analytical method using headspace gas chromatography. The matrix effects could be addressed by using matrix-matched calibration curves. The chromatographic analysis was linear and selective for D-limonene between 0.025 and 3.00 µg mL^-1, with correlation coefficients higher than 0.99. The analytical method had limits of detection and quantitation of 0.024 and 0.073 mg g^-1 for gelatin and 0.039 and 0.119 mg g^-1 for lignin, respectively.