Dairy products like milk, cream, or even yogurt can be evaporated to dryness in order to produce a powder with increased shelf life and easy handling. These powders are then conveniently used to produce delicacies like chocolate, pastries, or ice cream. Powdered milk is produced by spray-drying which is a well established method in food technology but also in the chemical or pharmaceutical industry.
For spray drying, the milk is first pasteurized, and then transferred to a spray tower where it is dispersed through tiny nozzles (atomizers) into 200°C hot air. The droplets immediately loose most of the residual water and the water content is reduced from 87,5% to 3% in the process. The result is a fine powder with a typical particle size distribution between 20 µm and 500 µm. The size distribution affects properties like dissolution, reconstitution, or flowability and is therefore a quality relevant feature.Meer zien