The contribution of milk fat towards the caking of dairy powders

Milk fat has a role in the caking of dairy powders during storage. The cohesiveness of six powders was studied by exposing the powders to temperature fluctuations whilst keeping the amorphous lactose component stable. It was found that caking was related to the amount of crystallised surface fat present on the powder. There was no measurable increase in the cohesiveness of the powders when only liquid fat bridging was present. An increase in cohesiveness was only found when the fatty liquid bridges were able to partially solidify due to a decrease in powder temperature. It is important to avoid elevated temperatures in bulk packed powders if the surface fat levels are above 13% (w/w), corresponding to a total fat content of 41% (w/w). Heating and subsequent cooling of such powders results in significant caking problems.