First-order Modeling of Wall Composition and Outlet Temperature Effects on Particle Morphology and Antioxidant Properties of Spray-dried Pequi (Caryocar brasiliense) Pulp Powders
Caryocar brasiliense (pequi), a native fruit of the Brazilian Cerrado, is a rich source of bioactive compounds—particularly carotenoids and phenolics—yet its high lipid content and pronounced seasonality restrict industrial utilization. This study evaluated the effects of wall material composition (maltodextrin, MD, and whey protein concentrate, WPC, at varying ratios) and outlet air temperature on the physicochemical and morphological properties of spray‑dried microencapsulated pequi pulp. A fractional factorial Box–Hunter design was applied using the following independent variables: outlet air temperature (80–90 °C), MD concentration (10–20%), and WPC concentration (0–10%). The resulting powders were characterized for physicochemical, morphological, and antioxidant properties (total phenolic content (TPC) and ABTS, DPPH, and FRAP assays). The processing variables significantly affected particle characteristics, with WPC concentration showing the strongest positive influence on phenolic retention and antioxidant capacity. Among the evaluated experimental conditions, the 10:10 MD:WPC ratio and outlet air temperature of 80 °C resulted in the highest retention of total phenolic compounds and antioxidant activity, while maintaining desirable physicochemical properties. The agreement between predicted and observed values under this condition indicated adequate model performance within the experimentally investigated domain. Overall, microencapsulation of pequi pulp is an effective technological approach for producing functional ingredients, reinforcing the value of predictive modeling in optimizing spray‑drying operations for industrial applications.