Figure 5: A schematic of the key steps in ice cream processing.
At the most basic level, it is impossible to form a uniform product if the fat has creamed off and other ingredients have sedimented. The rate at which an ice cream emulsion separates is determined by the particle size and density of the dispersed phase, as well as the viscosity of the continuous phase. The goal, therefore, is to optimise the level of stabilisers in the recipe and ensure that the homogenisation process reduces the particle size sufficiently.
One method that allows stability to be examined directly is the lumisizer. This test uses centrifugal force to accelerate separation while tracking the amount of material that creams-off and sediments. The resulting data can be used to:
1. Visualise the final state of the emulsion
2. Create an instability index in order to compare the effect of different formulations and optimise the processing conditions
Conducting complementary techniques, such as microscopy and rheological measurements, will also help to gain deeper understanding of the emulsion. These valuable insights save the company time and money, while also ensuring a successful and viable scale-up.