Developing and utilizing a mini food powder production facility to produce industrially relevant particles for functionality testing

In this thesis is presented research relating to a monodisperse droplet dryer for production of milk powder. The development and testing of several monodisperse droplet generators and lab-scale spray dryers was carried out. Furthermore, a number of down-scaled techniques for quality measurement were devised for analysis of the powder. Sufficient amounts of highly uniform powder could be dried to low moisture contents, using a range of feed solids concentrations and drying air temperatures. A single droplet drying model was created to simulate the situation, based on established mass and heat transfer equations and material specific kinetics using the Reaction Engineering Approach. Through a series of experiments varying drying temperature and feed solids content for a number of feed materials, the model was validated and its limits of accuracy were established. It successfully predicted the true final moisture contents and insolubilities in a range of conditions. The known and uniform temperature history and the regular particle sizes were then used to conduct original research on the formation of insoluble material during powder heat damage and the formation of particle morphology and shrinkage. Work was also done on spray freeze drying, thin layer drying, powder wetting, dissolution and the addition of surfactants.