Comparison of a uniaxial force displacement tester with a ring shear tester for assessing powder cake strength

This article highlights the use of a novel easy to use uniaxial force displacement tester (FDT) for measuring powder cake strength. A comparative study was undertaken of the FDT with a standard ring shear tester (RST) for measuring the cake strength of a powder. The powder used in the study was maltodextrin DE 21 which is an amorphous powder which readily cakes at temperatures at or above its glass transition. The powder was first equilibrated at 50% relative humidity over a five month period and it was then exposed to temperatures at and above its glass transition. The powder cake strength was measured using both the FDT and RST and the measured results were compared. The results showed that the cake strengths measured by the FDT correlated well with those of the RST. This demonstrated that the FDT is a realistic, easy to use method for assessing the cake strength of a powder.