Some aspects of measuring the size and rate of dispersion of milk powder agglomerates using the Malvern Particle Sizer 2600c

Abstract

SummaryThe Malvern Particle Sizer, which applies Fraunhofer light diffraction theory, has recently become popular for measuring particle size distributions in dried milk and other powders. The size distribution is obtained by dispersing the powder in air or a suitable liquid in the laser light beam of the instrument. The suitability of the dry powder dispersion system (DPD system) of the Malvern Particle Sizer 2600c for characterizing agglomerated milk powders was examined. It was found that, although the instrument gave reproducible and reliable results for non-agglomerated powders (standard milk powders), milk powder agglomerates could be broken in the standard DPD system and erroneous size distributions might be obtained. However, the DPD system had potential for providing an objective test of the mechanical stability of milk powder agglomerates. In addition, the transient size distribution during dispersion of an instantized agglomerated milk powder in water was measured at intervals of about 20 s.