Encapsulation of purple maize anthocyanins in phosphorylated starch by spray drying

Phosphorylated starch was prepared and evaluated as an encapsulating agent for purple maize anthocyanins under several inlet air temperatures (130-170°C) and different concentrations (10-20%) of phosphorylated starch during the spray-drying process. Phosphorylation was carried out by reactive extrusion with 4% sodium tripolyphosphate as a crosslinking agent at pH 5. The derivatization resulted in the loss of crystallinity, low viscosity, and high solubility of the starch. A band at 1,569 cm^-1 in the FTIR spectrum attributed to the purple maize anthocyanins was observed in the microcapsules. The drying process yield ranged from 25.67 to 49.11%. The highest drying yield (49.11%) with encapsulation productivity of 87.63% resulted with 20% solids at 170°C. The higher the concentration of phosphorylated starch, the better the anthocyanin protection during the spray-drying process was, in which smoother microcapsules were observed by scanning electron microscopy.