Prediction of storage stability parameters of spray dried powders of maltodextrins and corn syrups with different levels of hydrolysis (conversion)

The aim of this work was to establish the maximum stability conditions of maltodextrins and corn syrups obtained by spray drying with different levels of starch hydrolysis as dextrose equivalent (DE) 10, 20, 30 and 40 from a thermodynamic study of sorption at 25, 35 and 40°C. These storage conditions were correlated with the hygroscopicity, glass transition temperature (Tg) and external morphology of these powders to minimize physical phenomena such as caking. The conditions of maximum stability according to the minimum integral entropy (DSint) for maltodextrins (DE 10 and 20) fluctuated between aW of 0.12 to 0.25 at 25°C with hygroscopicity of 26 % and Tg of 112 ° C, while for corn syrups (DE 30 and 40) aW between 0.03 to 0.05 at 25°C, with hygroscopicity of 36% and Tg of 89°C; For the same value in DE as the temperature increases, the humidity (M) and the aWof maximum stability decrease, while for the same temperature, the increase in DE also decreases the humidity (M) and aW of maximum stability, maintaining their structural integrity without compaction; in extreme conditions, the powders showed a greater or lesser degree of caking.

Keywords: Hygroscopicity; Sorption moisture; Water activity; Minimum integral entropy; Glass transition temperature; Maltodextrins; Hydrolysis level.