Glass transition and flowability/caking behaviour of maltodextrin DE 21

Maltodextrin DE 21 is a spray dried amorphous powder that is commonly used as an ingredient in the food industry. The powder or an ingredient mix containing the powder can form very strong cakes if exposed to certain consolidating pressures and climatic conditions. In particular, it was believed that the glass transition can influence its caking behaviour. Consequently, the focus of this study was to investigate the influence of exposing maltodextrin DE 21 powder to temperatures around its glass transition and to measure its flowability or cake strength using a ring shear tester. To enable this work, the influence of water content on the onset glass transition temperature was measured along with the sorption isotherm of the powder. The ring shear testing showed that the maltodextrin powder readily formed a very strong cake over time when it was exposed to temperatures that were at or above its onset glass transition temperature. Maintaining the powder temperature at 4 degrees C below its glass transition should prevent the powder from caking. (C) 2013 Elsevier Ltd. All rights reserved.