Inside Ice Cream

We are a nation of ice cream lovers! Each person in the UK eats an average of 6 litres of ice cream every year.

Ice cream is mainly made of water, fats, proteins and sugar, all blended together with air bubbles whipped in, making a delicious creamy treat. Freshly made ice cream tastes good but, when it’s been in and out of the freezer several times, something doesn’t seem quite right.

Using X-ray tomography at Diamond, working in collaboration with Unilever, the Lee Group studies detailed structure at micron scales to understand how the different components mix together and examine what happens to them as we warm and cool the ice cream.

Fresh ice cream has small, rounded ice crystals, but if ice cream is warmed and refrozen many times, these crystals grow to become large and spiky.

Series of tomographic images taken with Diamond of the ice crystals inside ice cream. The crystals grow from small and rounded to large and spiky as the ice cream goes through cycles of warming and cooling.

 

Tingling Tongues
When you eat an ice cream, the crystal shapes affect your tongue in different ways. Round crystals from fresh ice cream barely move the taste-buds giving it a creamy feel. Refrozen, spiky crystals poke into the tongue, making the ice cream feel grainy and less pleasant.

Controlling Crystals
Traditionally, fat is used to keep the ice crystals round, but by using 4D science we can see how the proteins in the mix control the crystal shapes.  By studying their behaviour we aim to find ways to stop the large, spiky crystals forming.

Tomographic image showing the matrix structure of ice cream that has been warmed and cooled many times.

 

Watch our video showing inside ice cream