Microencapsulation of Rosemary Essential Oil: Characterization of Particles

Abstract

This study evaluated the influence of wall material concentration (10–30%), inlet temperature (135–195°C), and feed rate (0.5–1.0 L · h⁻¹) on the properties of rosemary oil microencapsulated by spray-drying, with gum arabic as carrier. Powder recovery, surface oil, oil retention, and hygroscopicity varied from 17.25%–33.96%, 0.03%–0.15%, 7.15%–47.57%, and 15.87%–18.90%, respectively. The optimized conditions were determined to be a wall material concentration of 19.3%, an inlet air temperature of 171°C, and a feed flow rate of 0.92 L · h⁻¹. At this condition, particles presented no fissures and the compositions of pure and microencapsulated oil were similar. The sorption isotherms could be described by the GAB model.

Keywords:

• Encapsulation efficiency
• Flavor
• Gum arabic
• Response surface methodology
• Spray-drying

ACKNOWLEDGMENT

The authors thank FAPEMIG (Minas Gerais State Foundation for Research Development, Brazil) for the financial support.

Notes

X₁-wall material concentration, X₂-inlet air temperature, X₃-feed flow rate.

ns: nonsignificant (p > 0.05).

*Significant at 5% probability.

X_eq: equilibrium moisture content (g 100 g⁻¹ dry powder); X_m: monolayer moisture content (g 100 g⁻¹ dry powder); C, K: model constants related to monolayer and monolayer properties; aw: water activity; a,b: model parameters; E: mean relative deviation modulus; R²: coefficient of determination.