Effect of solid content and particle size on the flow properties of molten chocolate

The rheological properties of sugar and cocoa particle suspensions in cocoa butter under molten condition were analyzed with Haake rotationary viscometer. Both suspensions had yield value and showed rheopexy at low shear rate and thixotropy at high shear rate. Flow behaviors of the suspensions were analyzed with modified Casson model. Casson viscosity and yield value increased with increasing the concentration of sugar and cocoa particles. There was an obvious dependence of the Casson viscosity and yield value on the particle size distributions that were represented by the Sauter mean diameter of the particles. Casson viscosity and yield value of cocoa butter-sugar suspension increased with increasing the fineness of sugar particle crystal