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Ice Burned My Ice Cream!

Written by Patricia Rea
Edited by Michael Li
Illustrated by Elena Nguyen

A pink, cartoon ice cream cone with a worried expression is sitting on a bed of ice with icicles along its cone. Two blue protein characters flank the ice cream wearing medical caps and carrying first aid kits. The right protein is also carrying a bag labelled “ANTI FREEZE”. A blue icicle frame is drawn and in the background is a girl with a shocked expression, looking at the ice cream and proteins in the foreground.

Ice cream is meant to be smooth and cool, not crunchy and disappointing. Freezer burn happens when the frozen water molecules in food turn directly from a solid into gas instead of melting first¹. These water vapors then recrystallize on the surface of the food, leaving it icy and dried out. However, nature has a solution at the earth’s poles that could transform how we use our freezers — antifreeze proteins.

Right now, we mainly use chemicals such as ethylene glycol and propylene glycol to resist freezing². Ethylene glycol is a very effective antifreeze and cheap to make, but the body breaks it down into toxic compounds³, ⁴. This has led to the recent increase in use of propylene glycol, which has much lower toxicity and is biodegradable⁵. This makes it safe for food and cosmetics, but it’s more expensive than ethylene glycol and requires higher concentrations to achieve the same effect. At high enough concentrations, these chemicals work by physically blocking water molecules from forming an ice lattice⁶.

Antifreeze proteins (also known as AFPs) work a bit differently. They are small proteins that attach themselves to the surface of ice crystals and stop them from growing⁷. They were first discovered in fish in 1969⁸, but have also been found in plants, insects, bacteria, and fungi living in extreme conditions⁷. Unlike traditional antifreezes, the function of AFPs isn’t dependent on concentration. AFPs contain an ice binding site, which is a region of the protein that can attach to water molecules in an ice lattice. By attaching to ice crystals, AFPs can restrict their growth, and prevent freezing much more effectively than ethylene glycol and propylene glycol. This method of preventing freezing means that less AFPs are required than chemical antifreeze to achieve the same result.

Various photos on a desk showing the steps of eel life history connected by a red thread. The top 3 photos are polaroids with the name of the stage of development and location in the margins, while the bottom 2 are photos with stage of development and location in the background.

All antifreezes do two things. First, they significantly lower the freezing point of water below 0 °C, which prevents freezing⁷. Second, they raise the melting point of water slightly above 0 °C. This allows AFPs to prevent ice cream from getting freezer burn by preventing ice growth and shrinkage. They also allow it to melt slower when out in the sun, all while being non-toxic and working at much lower concentrations than ethylene glycol and propylene glycol.

Ice cream and popsicles aren’t the only products that can benefit from AFPs. They can help to prevent freezer burn in many different foods, lengthening their shelf life⁹. Crops that are grown in cold climates can also be genetically engineered to produce AFPs, increasing their resistance to cold. Additionally, in medicine preserving donor organs can be a big challenge, as ice from freezers can leave the organ too damaged for transplants¹⁰. AFPs could help a higher number of organ donations remain usable, as well as aid the preservation of cells and tissues in research laboratories.

With all these utilities, AFPs have begun to be used in several different products. Health Canada published a consultation document in 2014 outlining their toxicity studies on a specific AFP (referred to in the food industry as an “ice structuring protein”)¹¹. They found no evidence of toxicity or similarity to any known allergens, leading to the protein being approved as a food additive¹². Also, in 2005, the international food company Unilever filed a patent to use AFPs in some of their ice cream products¹³, ¹⁴.

 The AFPs used in products aren’t harvested from fish or insects. Instead, yeast is genetically engineered with DNA that produces these proteins¹¹. Scientists then purify these AFPs so that they can be used in products like ice cream. Turning yeast or bacteria into biological factories allows us to mass-produce proteins and enzymes like AFPs more efficiently than using animals. For example, insulin is currently being made like this¹⁵. With these advances, we are closer than ever to finally defeating freezer burn in our ice cream!

Sources:

  1. Danahy A. Freezer burn: What it is, food safety, and tips for prevention. Healthline. 2025 Nov 3 [accessed 2025 Nov 19]. https://www.healthline.com/nutrition/freezer-burn#causes
  2. Chant J. The difference between propylene glycol and ethylene glycol in antifreeze. Industry News. 2023 Feb 9 [accessed 2025 Nov 19]. https://www.monarchchemicals.co.uk/Information/News-Events/700-/The-difference-between-Propylene-Glycol-and-Ethylene-Glycol-in-antifreeze#:~:text=The%20main%20difference%20between%20propylene,any%20human%20or%20animal%20exposure.
  3. Moutoux M. Choosing propylene vs. ethylene glycol. Atom Chemical. 2024 Mar 1 [accessed 2025 Nov 19]. https://www.atom-chemical.com/blog/choosing-propylene-vs-ethylene-glycol
  4. Ethylene glycol and propylene glycol toxicity: What is the biological fate of ethylene glycol? Centers for Disease Control and Prevention. 2022 Oct 6 [accessed 2025 Nov 19]. https://archive.cdc.gov/www_atsdr_cdc_gov/csem/ethylene-propylene-glycol/biological_fate.html
  5. Industries C. Propylene glycol safety: How to handle antifreeze solutions. Clear Water Industries. 2025 Mar 10 [accessed 2025 Nov 19]. https://clearwatershelton.com/propylene-glycol-safety/
  6. Elliott GD, Wang S, Fuller BJ. Cryoprotectants: A review of the actions and applications of cryoprotective solutes that modulate cell recovery from ultra-low temperatures. Cryobiology. 2017;76:74–91. doi:10.1016/j.cryobiol.2017.04.004
  7. Bar Dolev M, Braslavsky I, Davies PL. Ice-binding proteins and their function. Annual Review of Biochemistry. 2016;85(1):515–542. doi:10.1146/annurev-biochem-060815-014546
  8. DeVries AL, Wohlschlag DE. Freezing resistance in some Antarctic fishes. Science. 1969;163(3871):1073–1075. doi:10.1126/science.163.3871.1073
  9. Naing AH, Kim CK. A brief review of applications of antifreeze proteins in cryopreservation and metabolic genetic engineering. 3 Biotech. 2019;9(9). doi:10.1007/s13205-019-1861-y
  10. Tas RP, Sampaio‐Pinto V, Wennekes T, van Laake LW, Voets IK. From the freezer to the Clinic. EMBO reports. 2021;22(3). doi:10.15252/embr.202052162
  11. Canada H. Government of Canada. Canada.ca. 2014 Jan 3 [accessed 2025 Nov 19]. https://www.canada.ca/en/health-canada/services/food-nutrition/public-involvement-partnerships/use-new-food-additive-structuring-protein-modify-texture-unstandardized-edible-ices-unstandardized-frozen-desserts/consultation.html
  12. Canada H. Government of Canada. 8. List of Permitted Food Additives with Other Accepted Uses (Lists of Permitted Food Additives) – Canada.ca. 2025 Oct 20 [accessed 2025 Nov 19]. https://www.canada.ca/en/health-canada/services/food-nutrition/food-safety/food-additives/lists-permitted/8-other-accepted-uses.html
  13. Fletcher A. Unilever’s revolutionary GM ice cream protein challenged. BakeryAndSnacks.com. 2006 Jul 12 [accessed 2025 Nov 19]. https://www.bakeryandsnacks.com/Article/2006/07/13/Unilever-s-revolutionary-GM-ice-cream-protein-challenged/
  14. Reidhead P. Unilever (Breyer’s & Good Humor) Using Genetically-Modified Fish “Antifreeze” Protein in Ice Creams. Say no to gmos! – december 2006a. 2006 Dec [accessed 2025 Nov 19]. https://www.saynotogmos.org/ud2006/udec06a.php
  15. Levy M. Insulin Development and Commercialization. American Chemical Society. [accessed 2025 Nov 19]. https://www.acs.org/education/whatischemistry/landmarks/insulin.html

 

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