Influence of particle size on the solubility and the dispersibility of dried milk and cocoa powder

The influence of the size of particles on the solubility and dispersity of milk powder and cocoa powder were investigated. Six milk powder samples produced by the spraying process, with different fat contents and by different producers were investigated. Apart from milk powder, one cocoa powder sample and one instant cocoa-beverage sample were investigated too. On the basis of the obtained results the following conclusions were drawn: The higher the fat content in milk powder, the smaller the water content and acidity. Solubility of milk powder depends on the size of particles being the best in the samples where the particles were smaller than 1X10- m, and much worse in milk powder with particles larger than 1x10- m. Milk powder has a better dispersity if it contains less fat and more larger particles, 1.189x10-to 1x10- . Cocoa powder has much smaller particles (0.4 x 10- to 16x10- m), and owing to this, its solubility and dispersity are much lower. There is a very high correlation between the size of larger particles (1x10- to 0.189x10- m) and the poured in volume density, solubility and dispersity, while the correlation between the size of smaller particles (0.189x10- to 0.038 x 10- m) and the enlisted physical properties was found to be lower.