Microencapsulação do óleo essencial de cravo-da-índia (L.) por secagem por atomização

Abstract

The objective of this work was to investigate the effect of the ultrasound and of the different proportions of gum arabic/maltodextrin over the characteristics of food emulsions and microcapsules of Indian clove essential oil. The influence of the emulsification method (conventional and ultrasound) and of the proportion of gum arabic (100, 75, 50, 25 and 0%) was evaluated using a completely randomized design in factorial scheme with three replicates. The use of ultrasound produces thermodynamically more stable emulsions with smaller droplets, low polydispersity index, higher viscosity. The size of the particle was influenced by the proportion of gum arabic and by the homogenization method. The use of ultrasound resulted in powders with higher moisture and higroscopicity contents and lower values of wettability and solubility. The highest values for particle density occurred in the treatment with no substitution of the gum arabic (100:0). The formulation with total substitution of the gum arabic for maltodextrin presented higher density values of the independent bulk of the homogenization process used. The ultrasound resulted in powders with higher values of compacted density, with the exception of the formulation with 50% of gum arabic. The microcapsules formulated with 100% of gum arabic presented lower efficiency values. The use of ultrasound improved oil retention, with the treatment of 75% considered the most efficient. The powders with higher concentration of maltodextrin presented smooth surfaces and, with only gum arabic, they presented cracks. The behavior of the sorption isotherms was better described by the GAB model. The use of ultrasound allied to the increase in the concentrations of gum arabic favored the increase of water adsorption. The formulation with 50% of gum arabic presented the lowest thermal resistance. In general, the substitution of 25% of gum arabic allied to the emulsification process by ultrasound resulted in more thermally stable particles with better characteristics. The ultrasound can be used as an efficient alternative to homogenize food emulsions for atomization drying.