Crystallization of Amorphous Components in Spray-Dried Powders

Abstract

Spray-dried powders are typically produced as amorphous particles. Long storage of the particles tends to crystallize the powders, a reaction affected by moisture, time, and temperature. This work has examined partial crystallization from amorphous spray-dried powders by moisture sorption. Powders of citrus fiber with hibiscus extract, maltodextrin, coffee, tea, skim milk, and sucrose were produced with a laboratory-scale spray dryer. The powders were exposed to ambient temperature and various relative humidities, with weight measurements recorded over time. It has been found that, in different materials, the amorphous to crystalline state change is observed at varying rates depending on the relative humidities and molecular weights. This observation may be associated with all amorphous spray-dried materials.