Influence of environmental conditions on caking mechanisms in individual amorphous food particle contacts



Caking of amorphous powders creates severe problems such as product loss and additional costs in the food industry. Among the main factors causing this unwanted agglomeration process are fluctuations of the environmental conditions, that is, a rise in temperature and humidity. There is correspondingly a need to identify and, if possible, avoid the environmental conditions inducing strong interparticle cohesion based on particle contact mechanisms like viscoelastic flattening and sintering. For this reason, a novel micromanipulation approach focusing on the interactions between individual amorphous food particles in contact under load in a controlled environment is introduced. It was possible to identify the dominant caking mechanism under defined conditions, such as temperature and humidity, particle deformation, as well as contact holding time, and to quantify interparticle cohesion. Furthermore, the mechanical behavior of rubbery spherical model particles is presented and a theoretical approach to describe the contact zone formation kinetics is proposed. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2774–2787, 2014