Single droplet investigation on the levitator to explain the drying kinetics and morphology formation of maltodextrin DE < 3 and DE 21

Abstract

The investigation of single droplets in the acoustic levitator has been increasingly used in recent years to study their behavior during the drying process. By selectively flowing conditioned air onto the droplets and controlling the ambient conditions, it is possible to observe the drying behavior without contact under conditions similar to those prevailing in spray drying. A CMOS camera is used to continuously measure the change in volume that occurs during drying and an infrared camera is used to measure the surface temperature of the droplets/particles. The data are used to calculate the drying kinetics and the drying parameters with a high degree of accuracy. In addition to the suspensions investigated so far, the drying behavior of the solutions should be examined more closely. Since the drying kinetics of the solutions are complex and depend on the concentration and the material properties, two different maltodextrins (DE <3 and DE 21) and their solutions in different concentrations at different temperatures were investigated. Maltodextrin is a product that dries mainly in the falling rate period. From the results, conclusions were drawn concerning the structural development of the final particle and the average viscosity of the solution during the drying process.

Keywords:

• Drying kinetics
• ultrasonic levitation
• maltodextrin
• morphology
• viscosity