Optimization of spray drying process parameters for tucupi powder using the response surface methodology.

A completely randomized 23 factorial experimental design was used to optimize the process parameters for obtaining tucupi powder through spray drying. The effects of the process variables [inlet air temperature (IT), feed flow rate (FR), and maltodextrin concentration (MD)] on the product properties [moisture, water activity (aw ), hygroscopicity, water absorption index (WAI), water solubility index (WSI), total color difference (ΔE*), and β-carotene content] were studied using the response surface methodology (RSM) and linear perturbation plot. In addition, scanning electron microscopy (SEM) images were obtained of the product. According to ANOVA and the regression coefficients (R2  > 0.90), the RSM models were significant and IT was the variable with the greatest impact on most of the responses. SEM shows that the powders obtained with higher IT and MD and lower FR were more uniform, with smooth and intact surfaces. The optimal conditions estimated for the process were IT at 214 °C, FR at 8.67 mL/min, and MD at 27%. Under those conditions, the product's minimum values of moisture (9.56 g/100 g), aw (0.101), hygroscopicity (37.45% d.b.), and ΔE* (17.05) and maximum values of WAI (6.68 g/g d.b.), WSI (84.77%), and β-carotene (13.72 µg/g) were estimated.