Optimization of the Microencapsulation Process of Açaí Extract (Euterpe precatoria Mart.) by Spray Drying and Its Effect on Bioactive Content, Solubility Capacity, and Hygroscopic Stability

Euterpe precatoria Mart. (açaí) is a superfruit with high nutritional and functional value; however, its high perishability accelerates the degradation of its bioactive compounds. Therefore, technologies such as microencapsulation allow for its preservation, improve its bioavailability, and extend its shelf life. The objective of this study was to optimize the microencapsulation process of açaí extract via spray drying, using response surface methodology (RSM) and a central composite design (CCD), in order to evaluate the effect of inlet air temperature (IAT) and the gum Arabic: maltodextrin (GA:MD) ratio on the total phenolic content (TPC) and total anthocyanin content (TAC), antioxidant capacity (ABTS, DPPH), as well as on the water-solubility index (WSI) and hygroscopicity (HYG) of the resulting powder. The desirability function (D) indicated that an IAT of 135 °C and a GA:MD ratio of 25:75 constitute the optimal conditions for spray-drying the açaí extract, under which the following values were obtained: 93.49% WSI, 7.42% HYG, 3291.22 mg GAE/100 g TPC, and 115.89 mg C3G/100 g TAC. Experimental validation yielded values within the 95% confidence interval established for the model’s predictions. Scanning electron microscopy analysis (SEM) revealed predominantly spherical açaí powders with smooth or slightly wrinkled surfaces, and microparticle diameters ranging from 2.10 to 24.22 μm. This indicates that, under the conditions evaluated, favorable results were obtained in terms of the physicochemical properties and the retention of TPC (up to 92.15%) and TAC (up to 84.60%) in the powder. Therefore, these results provide an experimental basis for the development of value-added products from Amazonian fruits.