Effect of temperature shocks on the caking of moisture-sensitive amorphous powders

Abstract

Caking in amorphous powders is frequently caused by sintering at particle contacts. The molecular mobility and hence viscosity at these contacts depends delicately on temperature and concentration of plasticizers and specifically for carbohydrate matrices, water is a very effective plasticizer. In scenarios with rapid temperature changes, drying at particle surfaces reduces plasticization whereas it is promoted by the elevated temperature itself. In this paper, we combine particle-based simulations, experiments, and a percolation analysis to study the effect of sudden temperature rise on the caking of amorphous food powders. We show how and when a sudden change in temperature may lead to rapid percolation and hence powder caking, where caking time depends not only on the matrix properties, but also strongly on the particle size distribution. • Caking of amorphous powders is studied using a particle-based model. • An abrupt temperature increase changes the humidity and viscosity of the particles. • Particle sintering is affected by competing particle drying and bridge formation. • The phase plot of the caking time agrees qualitatively with experiments.