Nicely Frosty

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A research team discovered a novel way to prevent ice cream from becoming icy and crunchy after long periods in the freezer, Cosmos Magazine reported.

Ice cream tends to lose its softness because of tiny ice crystals in it: These crystals are very small – less than 50 micrometers – but when they grow, they add a crunch to the icy dessert.

Lead author Tao Wu and his colleague searched for a natural additive that could prevent the formation of large ice crystals. As such, they decided to test cellulose, a polysaccharide that is commonly found in nature and that is also amphiphilic – meaning it can repel and attract water.

For their experiments, researchers added cellulose nanocrystals to “model ice cream,” which were solutions with different concentrations of sucrose.

Their findings showed that cellulose was able to prevent the formation of large ice crystals but its effectiveness depended on the freezing period and sucrose concentration.

In one example, the peculiar additive completely halted the ice crystals from getting larger after five hours in the freezer: The ice crystals couldn’t grow more than 25 micrometers – well below the crunch limit.

The team added that cellulose nanocrystals worked by attaching themselves to the surface of the ice crystals and stopping them from growing.

Wu suggested that the novel method can also be used to preserve other frozen foods and organs.

“At present, a heart must be transplanted within a few hours after being removed from a donor,” he said. “But this time limit could be eliminated if we could inhibit the growth of ice crystals when the heart is kept at low temperatures.”