When prepared with the right ingredients and care, it becomes so elastic and pliable that Kirshenbaum says people have been photographed jumping rope with it.
It is traditional Turkish ice cream, known as Maras dondurma.
The researchers are finding that the stretchiness depends on a combination of all these things, says Arielle Johnson, an undergraduate chemistry major who has been working on the ice cream as part of an independent study project.
The two unusual Turkish ice cream ingredients, salep and mastic, probably contribute to the ice cream’s mysterious elasticity because they both contain polymers.
Johnson, from Kirshenbaum’s lab, admits that you can make the ice cream without mastic, but she says that the dried resin gives it more stretchiness.
Two Turkish researchers who have investigated the ice cream’s properties have not looked at mastic—it is not always included in the dessert because it is a flavoring ingredient.
But one of the researchers, Sevim Kaya, who is in the food engineering department at the University of Gaziantep in Turkey, writes in an email that the ice cream’s consistency is probably based on both the salep and the traditional processing.
The main polymers in salep are glucomannans, which are chains of sugar units, and in mastic there are poly-beta-myrcene polymers.
Kirshenbaum’s team is trying to understand what makes this traditional dessert so stretchy—whether it’s the unusual ingredients, the meticulous preparation or both.
And some Turkish ice creams are stretchier than others, says Kirshenbaum.