Structure-Based Design of Oil-Loaded Powders by Cast-Tape Drying: Effects of Maltodextrin Dextrose Equivalent and Plate Set Temperature

Abstract This study investigated the effects of maltodextrin (MD) dextrose equivalent (DE) and plate set temperature on the drying behavior and properties of oil-loaded powders produced by cast-tape drying (CTD). Medium-chain triacylglycerol oil was encapsulated in MD (DE = 4, 11, and 25). Benchmarked against freeze drying (FD), CTD drying kinetics at plate set temperatures of 60–90 °C were modeled using a Fick-type equation. CTD produced denser matrices and improved flowability, while oil retention remained at 79.4–87.5% and emulsion droplet size was largely preserved after reconstitution. CTD also lowered surface oil fractions, especially with low-DE MD, consistent with mobility-limited oil migration during rapid film formation. Rehydration behavior depended strongly on both the drying method and MD DE. For MD (DE = 25), the apparent dissolution rate constant decreased from 3.04 × 10–2 s–1 for FD powders to 1.61–2.23 × 10–2 s–1 for CTD powders, whereas no significant differences in the dissolution rate were observed between FD and CTD for MD (DE = 4). Browning increased with higher DE and plate set temperature, highlighting the need to manage browning reactions during CTD. Overall, the DE of MD and plate set temperature can be used as practical design variables to control oil distribution and powder properties in CTD powders.