THE EFFECT OF SPRAY DRYING PROCESSING CONDITIONS ON PHYSICAL PROPERTIES OF SPRAY DRIED MALTODEXTRIN

Maltodextrins have wide applications particularly in the food industry. They have many functionalities including usage as wall material, dispersing aid, flavor carrier, bulking agent, viscosifier or fat re-placer, and they exhibit only a slightly sweet taste. Maltodextrin was subjected to spray drying to determine the effect of spray drying conditions on moisture content, particle properties (particle size distribution and particle density) and bulk properties (bulk and tapped densities and porosity) of the powder product. Experiments have been performed in a lab scafle spray-dryer (BuchiLabortechnik AG, Flawil, Switzerland) using a full-factorial design to provide data and correlations that predict the powder properties as a function of the main operational variables of the spray-dryer. The inlet (140 and 200 degrees C) and feed temperatures (10 and 50 degrees C), feed flow rate (2.1x10(-4) and 9.6x10(-4) kg s(-1)) and atomizing air flow (1.3x10(-4) and 1.9x10(-4) m(3) s(-1)) were investigated as spray drying process variables. The effect of spray drying conditions on physical properties of powders was expressed with three dimensional response surface and perturbation graphs. Perturbation graphs revealed that atomizing air flow and inlet air temperature had more effect than feed temperature and feed flow rate on the physical properties of maltodextrin powder. The results showed that the Sauter mean diameter (D-3,D-2) was between 3.503 and 6.045 mu m for maltodextrin powders.