Abstract: The microencapsulation of purple corn anthocyanins by spray drying was optimized by response surface methodology. Air inlet temperature in spray drying was determined as the most important affecting factor of the percentage of embedded purple corn anthocyanins. The optimum microencapsulation conditions for purple corn anthocyanins were found to be: the content of total solids of 25%, consisting of 15% purple corn anthocyanins and 45% maltodextrin and air inlet temperature of 140 ℃.  Under such conditions, 95.2% of purple corn anthocyanins could be embedded. Scanning electron microscopic (SEM) observations and measurement in a laser particle size analyzer showed that the surface of microencapsulated purple corn anthocyanins at 140 ℃ air inlet temperature was smooth and uniform, and the particle size distribution was concentrated, with a peak being observed at 7.13μm.

Key words: purple corn, anthocyanins, spray drier, response surface analysis, scanning electron microscope