Serum separation in molten ice creams produced by low temperature extrusion processes

The microstructure and kinetics of serum separation due to creaming of air bubbles in molten ice creams produced using the novel twin and single screw low temperature extrusion processes are investigated. The measured fat globule size distributions are bimodal for both ice creams. However, the concentration of primary fat globules is much larger for the twin screw extruded ice cream than that obtained using single screw. The latter contained higher concentration of fat aggregates. A broader bubble size distribution involving larger bubbles is observed for the single screw extruded ice cream compared with that for twin screw process. The initial rate of serum separation in molten twin screw extruded ice cream. This is because the former ice cream contained smaller bubbles and the serum separated from it is more viscous due to the presence of more small fat globules. The initial rate of serum separation in molten twin screw extruded ice cream is less than half of that for the single screw extruded ice cream.