Production and characterization of starch microspheres using supercritical carbon dioxide assisted spray drying

Starch microspheres have gained attention in the pharmaceuticals, food, and cosmetics industries due to their versatility in controlled-release systems and product stability. However, traditional production methods present drawbacks, such as thermal degradation and inconsistent particle morphology, which can negatively impact product quality. This research investigates the production of starch microspheres using supercritical carbon dioxide (scCO₂)-assisted spray drying. The study examines the effects of key process parameters, including pressure (100-150 bar), temperature (45-55 °C), and spray rate (0.5-2 mL/min), on the characteristics of the resulting microspheres. Two starch types-native tapioca starch (NTS) and sodium trimetaphosphate cross-linked starch (STMP-CS)-were evaluated for their effects on morphology, particle size, size distribution, yield, and moisture content. Compared to conventional spray drying, the scCO₂-assisted method produced smoother, more uniform microspheres. STMP-CS demonstrated superior performance by yielding smaller, more uniform particles with higher production efficiency and lower moisture content than NTS. Among the processing parameters, pressure was the most critical, significantly affecting yield, particle size, and size distribution, while temperature and spray rate had minimal impact on microspheres properties.