Unboiling eggs


You can’t un-bake a cake, but it turns out you can now unboil an egg. Well, part of it anyway. Chemists from UC Irvine have worked out how to return boiled egg white proteins back to their original form using a novel process which takes only a few minutes. The idea behind the study was not to simply prove that this can be done, but that the new technique actually has a wide range of potential uses in a variety of applications, such as food production and even cancer research. The work has been published in ChemBioChem.

Eggs are a protein rich food; around 12% of the egg white is protein and the yolk is about 16%. Proteins are made up of chains of building blocks called amino acids which are folded and arranged in a very specific way, and it is this shape, among other characteristics, which bestows the protein its properties. When proteins are subjected to changes in pH or temperature, the bonds holding them together in a particular conformation are disrupted, causing the protein to unravel and tangle. This process is known as denaturation and is the reason that egg whites go from clear to white when cooked.

Denaturation presents scientists working in the lab with an issue, since it means that certain valuable proteins can’t be recycled after use. Furthermore, some proteins have a tendency to misfold shortly after they have formed, meaning they can’t be used at all.

“It’s not so much that we’re interested in processing the eggs; that’s just demonstrating how powerful this process is,” lead researcher Gregory Weiss said in a news-release. “The real problem is that there are lots of cases of gummy proteins that you spend way too much time scraping off your test tubes, and you want some means of recovering that material.”

Although techniques do exist to salvage proteins, they are costly and time-consuming, taking around 4 days. The newly developed method, however, takes just a few minutes. The researchers started off by boiling egg whites for 20 minutes at 90oC (194oF), plenty long enough to scramble the proteins. Then, to revert one of the main proteins in egg whites, lysozyme, back to working order, the researchers added a chemical called urea.

This compound, which is a waste product of many organisms, broke down the clumps of protein, returning the solid material into a liquid. Then, they placed the solution into a high-powered machine called a vortex fluid device which applied shear stress to the proteins, encouraging them to untangle and then re-fold to their original conformation.

Alongside demonstrating it is possible to effectively unboil eggs, the researchers believe their new method could have a range of uses in various industrial and research applications. For example; it has the potential to cut costs associated with the production of therapeutic antibodies which are often produced in costly hamster ovary cells, because proteins don’t tend to misfold in that particular environment.

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