偷拍偷窥

Nothing beats a frozen treat on a scorching summer day — until you face the race to finish before it all melts away. But now biochemists at the University of Wisconsin–Madison are working on creating ice cream that stays in the cone instead of dripping onto your hands — or the sidewalk.

is a recent Ph.D. graduate at UW–Madison and soon-to-be food scientist at General Mills. She spent her time in the lab perfecting her “” ice cream recipe. The secret? Polyphenols. 

MICHAEL KING, UNIVERSITY OF WISCONSIN–MADISON

Cameron Wicks, then a Ph.D. student at the University of Wisconsin–Madison, prepares samples of her “no-melt” ice creams for melting tests.

Polyphenols, also known as tannins, are naturally occurring compounds in fruits and vegetables that boast antioxidant properties and such as limiting inflammation. However, Wicks had a different purpose for these molecules in mind. 

She was inspired by a Japanese no-melt strawberry that went viral. “Someone even took a hair dryer to it just to see what would happen,” Wicks said in a Milwaukee Journal Sentinel . 

At UW–Madison, she applied the same principles used in the Japanese popsicle by adding polyphenols to cream and found that some of these molecules slowed its melting rate. 

an associate professor of food science and Wicks’ mentor, provided his expertise in creating sustainable foods to the project. “This is another ingredient we can add to our food science toolkit,” he said. 

However, finding the right ingredients and concentration of polyphenols required much optimization since polyphenols are a large family of molecules that include flavonoids, phenolic acids, lignans and more. 

By performing melting tests, Wicks narrowed down these molecules and landed on tannic acid as the polyphenol with the greatest “no-melt” effect on the ice cream.  

Michael King, University of Wisconsin–Madison

Ice cream scoops with varying amounts of polyphenols are subjected to melting tests.

When she examined the ice cream supplemented with tannic acid closely using a microscope, Wicks found that tannic acid links up with the water, fat and protein molecules to create a lattice network. This rigid lattice holds the water molecules in place, she explained, and doesn’t allow them to accumulate and create the drips you often see on your cone. 

“It’s more of a no-drip ice cream,” Wicks said. “The fat aggregates caused by the polyphenols are the reason why the system is able to hold water and the matrix for extended periods of time. … We believe polyphenols change the viscosity in comparison to a regular ice cream.”  

On top of minimizing drippage, adding polyphenols slowed the ice crystal growth that usually occurs when ice cream thaws and refreezes. This means polyphenol additives could help eliminate freezer burn and improve the shelf life of ice cream during distribution.  

“Ice cream doesn’t actually freeze all the way in your freezer,” Wicks said. “There’s a concentrated serum phase that contains water. With regular ice cream in stores, the transportation system to get it there and getting it home causes a lot of temperature abuse and freeze–thaw cycles. The matrix of polyphenols, proteins and fats makes it a lot harder for that water to be able to flow and grow to create large ice crystals.” 

Commercial ice cream contains stabilizers, such as guar and cellulose gums, that are designed to combat freezer burn. However, Wicks said, replacing these with polyphenols, such as blueberry powder, could eliminate ingredients that consumers are not familiar with and supplement the health benefits of sweet treats.  

“In our typical diets, we are not getting enough fruits, vegetables and whole grains, which are the major sources of polyphenols,” Bolling said. “So, if we can create a meal that includes polyphenols in the appetizer, main course and dessert, why not look for those applications? … This research project demonstrates the feasibility of that.” 

Future work at UW–Madison will focus on optimizing the taste and texture of ice cream that contains polyphenols. In addition, Wicks said she looks forward to introducing polyphenols into dairy-free ice creams, which have a faster than cream-based treats due to their high water content. 

“When you think about nondairy ice creams, there are a lot of challenges to overcome when creating a system that delivers a similar experience to its dairy counterpart,” Wicks said. “I'm definitely excited to see how this research might be able to help make nondairy ice cream better quality and more palatable.”