Thermal characterization of Arrabidaea chica (Humb. & Bonpl.) B. Verl. dry extracts obtained by spray dryer

This work aimed at characterizing Arrabidaea chica dry extracts obtained by spray dryer, after blending with gum arabic and/or maltodextrin in different proportions. Thermogravimetry, derivative thermogravimetry and differential thermal analysis were used to determine their thermal profile. Thermal analysis demonstrated that the blend containing 25% A. chica extract, 25% gum arabic and 50% maltodextrin had the strongest interaction between adjuvants and hydroalcoholic extracts, thus proving the best blending proportion. Infrared spectroscopy profile, which was used to infer the chemical composition of both the plant material and such a blend, showed typical absorption bands deriving from links of functional groups remained over the plant material. Scanning electron microscopy revealed a heterogeneous morphology of both dry extract and formulations with smooth surface and rough surface. Thermoanalytical techniques and spectrophotometry proved valuable tools to investigate physicochemical characteristics of formulations.