Alternative to Water Ice Reusable ‘Jelly Ice’ Keeps Things Cold — Without Meltwater

A squishy, reusable alternative to ice is on the horizon: researchers at UC Davis have developed “jelly ice” — a gelatin-based cooling material that keeps food and medicines cold without producing meltwater, is compostable, and can be reused across multiple freeze-thaw cycles.

No matter whether it’s crushed or cubed, ice eventually melts into a puddle — but an alternative called jelly ice doesn’t. Researchers Jiahan Zou and Gang Sun developed a one-step process to create the reusable, compostable material from gelatin, the same ingredient in jiggly desserts. Because frozen jelly ice doesn’t leak as it thaws, it’s ideal for food supply chains and medication transport. The team is also exploring protein-based structures for food-safe coatings and lab-grown meat scaffolds.

The jelly ice project started with a question posed to Zou and Sun by Luxin Wang, a food scientist at the University of California, Davis. Wang saw ice melting in grocery store seafood display cases and worried about meltwater spreading pathogens and contaminating the entire case. She asked whether the researchers could create a reusable material that functions like regular ice but doesn’t produce a potentially contaminated puddle.

The inspiration for the new material came from freezing tofu. Sun, a materials scientist also at UC Davis who advised Zou’s graduate research, explains that “frozen tofu keeps its water inside, but when you thaw it, it releases the water. So, we tried to solve that issue with another material: gelatin.”

Gelatin proteins have two properties that the researchers wanted: They are food safe, and their long strands link together, forming hydrogels with tiny pores that hold water, unlike tofu. Early tests of the hydrogels made with this natural polymer (also called a biopolymer) were a success. The water stayed inside the pores as it went through phase changes, from liquid to ice and back again, without damaging the structures or leaking out the hydrogel.

Through the years, Zou has optimized the gelatin-based hydrogels’ formula and production methods. Now, she has a practical, one-step process to create jelly ice that’s 90 % water and can be repeatedly washed with water or diluted bleach, frozen and thawed. The cooling material jiggles and squishes at room temperature. But when cooled below the freezing point of water, 32 degrees Fahrenheit (0 °C), it transitions to a firmer, more solid state.

“Compared to regular ice of the same shape and size, jelly ice has up to 80 % of the cooling efficiency — the amount of heat the gel can absorb through phase change,” says Zou, who will talk more about this when she presents the newest version of jelly ice at ACS Fall 2025. “And we can reuse the material and maintain the heat absorbance across multiple freeze-thaw cycles, so that’s an advantage compared to regular ice.”

The team can produce jelly ice in 1-pound (0.45-kilogram) slabs, similar to the cold gel packs currently for sale that have bulky plastic sleeves. However, the new cooling material has advantages over cooling packs or dry ice: It’s customizable for any shape or design, and it’s compostable. In one set of experiments, the composted gel improved tomato plant growth when applied to the potting soil. And because the cooling material doesn’t contain synthetic polymers, it shouldn’t generate microplastics.

Zou and Sun say that jelly ice, while initially developed for food preservation applications, shows promise for medical shipping, biotechnology, and use in areas with limited water available for forming ice.

Currently, there are licenses for the jelly ice technology. Zou hopes that this means the cooling material will be available to consumers as a meltwater-free, food contact-safe, compostable alternative to ice. Though, she acknowledges there are still some steps in market analysis, product design and large-scale production tests before it can be commercialized.

But as the gelatin-based jelly ice makes its way toward the market, Zou has also become interested in other natural biopolymers. She expanded her research into plant proteins that are agricultural by-products, such as soy proteins, to make more sustainable materials. Her focus is shifting toward developing soy proteins for removable countertop coatings and cellular scaffolds for cultivated meat. She’ll present more about that work at ACS Fall 2025.

“In my research, I realized how powerful Mother Nature is in designing biopolymers and the vast possibilities they offer,” says Zou. “I believe there will be amazing products derived from biopolymers as the materials themselves are teaching us how to work with them.”

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