Using a particle-gun to measure initiation of stickiness of dairy powders

A novel particle-gun technique has been developed for measuring the stickiness of dairy powders. Particles are impacted against a stainless steel plate using air at different temperatures and relative humidities (RH). The percentage deposition on the plate is used as a measure of the stickiness of the powders. Flow conditions similar to those existing in the ducts of commercial spray dryers are used in the test, making the results directly applicable to industry. The points where skim milk powders become sticky enough to form significant deposits at a given temperature, as measured by the particle-gun, occurred at significantly higher RH values than those measured by the other techniques with different flow conditions, such as stirring devices and fluidized beds.