Spray dried fruit juice powders are produced around the world. These powders contain fruit sugars and acids that make them
impossible to dry without the addition of a drying aid such as maltodextrin which is added to raise the glass transition of the
mixture. Thus, prediction of the glass transition temperature of mixtures is important when working out how much maltodextrin
to add and at what conditions to run the spray drier. Even with maltodextrin added, the powders have a strong tendency to cake.
This paper compares the glass transition temperature as measured over a range of water activities with a DSC with predictions
based on a simple additive model that uses the Gordon Taylor approach for predicting the effect of water of individual
component glass transition temperatures and the Fox equation. It demonstrates the development of caking between spray dried
lemon juice particles with time when the temperature of the powder is raised above the glass transition temperature using two
techniques.