Spray-dried thyme essential oil microparticles using different polymeric matrices

Abstract

The aim of this study was to evaluate the physical, physicochemical, rheological, and morphological properties and antioxidant capacity of thyme essential oil encapsulated by spray drying; as well as to verify the effects of the partial replacement of whey protein isolate by maltodextrin and chitosan. The presence of maltodextrin decreased viscosity of the emulsion; decreased moisture, density, and mean volume diameter, and maintained the oil retention percentage and solubility of the microparticles. All treatments showed low hygroscopicity, being chitosan considered an alternative to reduce this parameter. Phenolic monoterpene thymol was characterized as the major constituent in all samples. The carrier agents were efficient in maintaining antioxidant activity when compared to pure thyme essential oil. In general, they showed spherical shapes and smooth surfaces with slight roughness. The mixture of maltodextrin and chitosan, in partial replacement of whey protein isolate, represents a promising opportunity in obtaining thyme essential oil microparticles by spray drying process.