It’s unnatural to toss a fully loaded ice cream cone in the trash, but every year more than 500,000 tons of ice cream waste are thrown away by factories around the world. That’s enough to make a frozen pile larger than the U.S. Capitol building—complete with sled and toboggan runs. Scientists have now proposed that this waste could be recycled into a renewable supply of bio-diesel, aviation fuel, lubricants, or industrial solvents.
A new study published in Cleaner Engineering and Technology demonstrates how dairy fats can be separated from factory ice cream waste and sold as raw material for making these other products that might otherwise come from petroleum. This seemingly simple problem is surprisingly hard to solve.
Your typical pint of vanilla contains a mishmash of water, ice, sugar, proteins, and fat. The fats are dispersed in microscopic droplets that are coated in milk and egg proteins. The protein coatings prevent the fat droplets from merging and rising to the top, the way oil often does in a jar of organic peanut butter. And this, in turn, keeps your cold dessert smooth and creamy—so it won’t separate into oil and crunchy ice, even if you thaw and refreeze it.
But this culinary engineering also makes those valuable fats difficult to extract and purify from ice cream waste.
In this new study, researchers tested two strategies for stripping away the protein coatings, so the fat droplets will join together and rise, allowing fat to be skimmed off the top.
In one approach, they treated the ice cream waste with protease enzymes that slice apart the proteins coating fat droplets. In the other, they added acids or bases to either lower or raise the pH of the mixture, in order to unfold the proteins—causing them to fall off the fat droplets.
Both approaches worked to some degree; but the base treatment, raising the pH to 11, was faster and more effective. In as little as two hours, it recovered 95 percent of the fat from samples of ice cream factory waste, at purity levels up to 85 percent—while avoiding the expenses of intense heating or purchasing enzymes.
The authors calculated that this process could be done cheaply enough that the extracted fats could be sold for around $0.40 per gallon—making them cheaper than similar feedstocks that are often used to make fuels, solvents, or lubricants.
This strategy won’t eliminate the kilograms of ice cream fat that accumulate around our waistlines. But it could redeem the thousands of tons of fat that factories might otherwise throw away.
Ale-Enriquez, et al. “Low-cost fat recovery from industrial ice cream waste: Separation mechanisms, process modeling, and techno-economic feasibility.” Cleaner Engineering and Technology, 2026.
Image: ©Anthropocene Magazine
