Eating crunchy and icy ice cream can ruin the experience. Luckily, chemists have figured out how to ensure the ice cream stays creamy and soft.
Chemists claim that using a type of cellulose taken from plants can resolve the ice cream problem. The discovery could also be used for other frozen good and even organ and tissue donations.
Cellulose Discovery Can Fix Ice Cream Crunchiness
Ice cream sometimes gets crunchy because of the ice that accumulates in time while it is in the freezer. All ice cream has very tiny ice crystals in it.
If these crystals are small, less than 50 micrometers, they are not noticeable, and it does not change the taste of the ice cream. But the larger the crystal, the grainer and crunchier the ice cream becomes.
Manufacturers avoid massive crystals by freezing their ice cream fast at very low temperatures, usually with liquid nitrogen and with lots of agitation. However, according to Cosmos Magazine, if the ice cream lets and is placed in the freezer again, the texture is lost.
Dr. Tao Wu, a researcher in the Department of Food Science at the University of Tennessee, said that controlling the formation and growth of ice crystals is the key to creating high-quality frozen foods.
Dr. Wu and his colleagues looked to nature for a solution to prevent these crystals, regardless of how the ice cream is frozen.
Dr. Wu said that some fish, plants, and insects could survive in sub-zero temperatures because they produce antifreeze proteins that fight the growth of ice crystals. The proteins are expensive and difficult to make or extract, so they are not a practical ice cream additive.
Commercial manufacturers use another type of antifreeze: polysaccharides gums. These gums can reduce the massive crystals that form in ice cream, according to Eureka Alert.
However, Dr. Wu said that these stabilizers are not effective. The performance of the stabilizers are influenced by a lot of factors, including storage temperature and time, and the composition and concentration of other ingredients. This means that they sometimes work in one product, but they are not effective in another.
Dr. Wu noted that many effective types of antifreeze are amphiphilic, which means they are made of molecules that repel water in one part and attract water in another. He decided to investigate another polysaccharide: cellulose nanocrystals taken from plants.
According to Science Direct, cellulose nanocrystals are extracted from plants and trees through photosynthesis using carbon dioxide and water.
Discovery of Cellulose Nanocrystals
Aside from being made of the most common polymer in nature, cellulose nanocrystals are also amphiphilic so that they could do similar antifreeze work.
The researchers tested the cellulose nanocrystals by adding them to model ice cream, which consists of different concentrations of sucrose. They found that the freezing time and concentration played a massive role in how well the cellulose nanocrystals did their job.
At a concentration of 25% sucrose, similar to those used in commercial ice creams, the cellulose nanocrystals did not make any difference to the formation of ice.
However, after a bit of time, they kicked in, and a concentration of 1% cellulose stopped ice crystals from getting bigger after 5 hours. The ice crystals in the mixture could not get larger than 25 micrometers, which is below the crunch limit, and the crystals in the control solution.
When the cellulose concentration was halved to 0.5%, the ice growth stopped at 68 hours and 40 micrometers.
In 2014, Xamaleon released an ice cream that changes color when you lick it.
In 2021, an ice cream machine was released to turn alcoholic drinks into soft serve.
Related Article: Presenting Vegan Ice Cream, the New Technology of Ice Cream Making
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Written by Sophie Webster
