Steam-jet agglomeration of skim-milk powders : influence of the process parameters

Steam-jet granulation is a process used in the dairy industry to produce instant agglomerated milk powder. The agglomerate growth process includes wetting of the particle surface, collisions of sticking particles and consolidation of the agglomerates by drying. The aim of this study was to evaluate the influence of the raw material properties (initial particle size and humidity) and processing conditions (liquid/solid ratio and post-drying conditions) on the growth mechanisms and agglomerates properties. Skim milk powders were granulated using steam-jet granulation pilot and characterized via the in-size distribution, water content, structure, thermodynamical and functional properties. The water content and the post-drying time were identified as key process parameters to control in order to obtain instant agglomerated milk powder