Food suspensions study with SR microtomography

The incorporation of a small amount of secondary immiscible liquid to suspensions can lead to a shift from a fluid-like structure to a paste-like structure. This is ascribed to the higher attraction of the secondary liquid to the particles, in comparison to the continuous phase. However, visual observations on the micro-scale during both long and short term time-scales, dependant on the type of secondary immiscible liquid used are yet to be reported. In the current study, the movement of various secondary immiscible liquids (water, sucrose solutions, saturated sucrose solution and glycerol) when added to a model food suspension (sucrose particles in sunflower oil) was investigated. Dynamic X-ray computed tomography was used, as a non-invasive approach, to study the mass transfer on the micro-scale and to observe the bulk movement of sucrose within the suspension. It was found that the affinity of the secondary liquid in dissolving sucrose was the primary contributor to the secondary liquid movement, with density/gravitational effects playing a minimal role.