This study evaluated maltodextrin (MD) and gelatin (GEL) in different ratios (SO1, MD only; SO2, MD and GEL = 2:1; and SO3, MD and GEL = 1:1, respectively) as wall materials to microencapsulation of sweet orange essential oil (SOEO, 10% w/w). SOEO microspheres were obtained by emulsification/lyophilization and characterized regarding the microencapsulation yield and efficiency, infrared spectroscopy, ultrastructural aspects (scanning electron microscopy, SEM), thermogravimetric (TG), derivative thermogravimetry (DTG) and differential exploratory calorimetry (DSC) and bioactive properties. Yield and SOEO microencapsulation efficiency (MEE) was of up to 90.19 and 75.75%, respectively. SEM analysis showed SO1, SO2 and SO3 microspheres with irregular shapes. Although improvements in thermal stability of all formulated microspheres were observed, TG and DTG curves indicated slower rates of volatilization and degradation of SOEO in SO1. DSC curves indicated that SO1, SO2 and SO3 microsphere formulations were effective in protecting SOEO, especially in relation to improvements in oxidative stability. Antibacterial and antioxidant properties, as well as total phenolic content of SOEO, were maintained in all formulated microspheres. SOEO microspheres can be prepared using MD and GEL and lyophilization, resulting in high yields, MEE, stability and preservation of antioxidant and antimicrobial properties.
Keywords: Bioactive properties; Freeze-drying; Microencapsulation; Stability; Sweet orange.
Copyright © 2019 Elsevier B.V. All rights reserved.