Optimization of foam mat drying using Central Composite Design to produce mixed juice powder: A process and characterization study

This study aimed to optimize the mixed juice powder through foam mat drying to achieve a high solubility index. The process variables were optimized using a central composite design, assessing the influence of foaming agent concentration (5, 10, and 15) (% w/w), drying temperature (50, 60, and 70) °C, and foam thickness (2, 4, and 6) mm on powder solubility. The optimized juice was evaluated for the physical, chemical, technological characteristics and bioactive compounds. The optimal conditions were determined as a drying temperature (60.27 °C), foam thickness (2.82 mm), and 8.56 (% w/w) maltodextrin. The final product characterization revealed notable properties, including a soluble solids content of 8.75 °Brix, pH of 4.48 ± 0.01, and water activity of 0.44 ± 0.04. The analysis covered aspects related to color, porosity, sedimentation index, and solubility, highlighting a browning index of 0.81 ± 0.03. The powder microstructure exhibited a variety of shapes, reflecting the stability of the foam. The results confirmed the stability of the mixed juice powder, indicating that it maintained a consistent total carotenoid concentration of 10.65 μg/g and preserved its physicochemical characteristics. The cubic response surface model was the most suitable for solubility response with maximum value desirability (1.00). © 2024 Institution of Chemical Engineers (IChemE)