RCaH scientists find secret to better ice cream

22 Jul 2018

The taste and feel of ice cream are directly dependent on its microscopic crystalline structure. However, this structure changes if storage temperatures rise above -30°C, which is the case during transportation and also in domestic and supermarket freezers. This is potentially a problem for ice cream manufacturers, who want to preserve the unique taste of their ice cream. which is why an international team of researchers brought some samples to Harwell for help with the problem.

Using the equipment at the Diamond Light Source, researchers in Harwell blasted scoops of vanilla ice cream with X-rays to learn more about the temperature dependence of its microstructure, and the underlying physical mechanisms. They discovered that ice cream that had been ‘thermally abused’ – by being cycled at temperatures between -15°C and -5°C for several days – had bigger ice crystals and air bubbles. Further studies revealed the physical reasons for this: that melting and recrystallisation are responsible for changes to ice crystal size and shape during thermal abuse, whereas the changes in air bubble size and interconnectivity are mainly due to the bubbles coalescing.

Professor Peter Lee of RCaH said: ‘This work also revealed other interesting phenomena, including the role of the unfrozen matrix in maintaining the ice cream’s microstructural stability and the complex interactions between ice crystals and air bubbles. For example, the melting and recrystallisation of ice crystals significantly affect the air bubbles’ morphology and the behaviour of the unfrozen matrix.’