Characterization of sorbet microstructure by using X-Ray microtomography.

Sorbet is a complex multiphasic system composed of a dispersion of ice crystals and air bubbles inside a concentrated liquid matrix. The functional properties and quality attributes of the finished product are mainly related to ice crystal and bubble size distributions. These latter are strongly dependent on operating conditions and also on the formulation. The use of a non-destructive 3D imaging technique is a real advantage for a better visualization and understanding of the frozen microstructure. In this study, X-Ray microtomography coupled with a cooling stage was used to visualize and quantify at negative temperature the sorbet microstructure after freezing. An image analysis protocol was developed to segment frozen phase from unfrozen matrix. The resulting images allow the determination of ice and bubbles size distribution and show the influence of the formulation on the sorbet microstructure.