The headline glared at me: "How to unboil an egg".
I wondered if this was possible; I was sure it violated some law of physics. Even The Scriptures tell us that things cannot be returned to their initial state once some change has happened: Isaiah 55:10 ESV "For as the rain and the snow come down from heaven and do not return there but water the earth, making it bring forth and sprout, giving seed to the sower and bread to the eater,..."
Perhaps it was an early April Fool joke. But no, my advisers have assured me that the chemistry is feasible, even if the headline has been exaggerated (by journalists or sub-editors) in order to grab our attention.
The short version of the egg story is that a group of chemists have made coagulated (cooked) egg-white turn back to a clear gelatinous substance. They have not really "unboiled the egg", but instead they have used legitimate chemical and mechanical procedures to totally reprocess the mixture. Because this takes quite a lot of energy and is in no way a spontaneous reaction (such as the initial cooking), the second law of thermodynamics is still totally intact. (This law implies that a spontaneous process will result in more disorder – you need to put energy into a process if you want to create an ordered system).
The chemists have done the equivalent of putting a deck of cards back into organised suits after the cards have been shuffled. It does not happen spontaneously, but you can make it happen by putting in some degree of effort to re-sort them by hand. You are not really "unshuffling" the cards, you are doing a new and legitimate process to make them into an ordered state again.
The nature of raw and cooked egg-whites.
WARNING – some science terminology in this section.
It is the 10% of proteins in an egg white that are responsible for its uncooked guey, jelly-like nature. The rest is mostly water. This particular protein solution provides protection for the growing embryo in the yolk, and extra nutrition for it as it grows.
Proteins in nature come in a wide variety of forms, with a huge array of functions. There are 20 amino acids that are connected in a specific way in long chains to make proteins, but each functional protein has a different combination of these building blocks, and a different length. Depending on the chemical properties of those amino acids, some proteins will naturally fold up or scrunch up in different ways – for example muscle proteins have a totally different structure from the digestive enzymes (also proteins) in your stomach, and these are different again from those in the egg white.
If any protein in a living organism becomes "mis-folded" or "unfolded" from its natural state, then that protein will not function properly. This is what probably happens in Alzheimer's disease (and some other medical conditions).
The egg-white proteins are folded into loose ball-shapes (the technical term is "globular proteins"), and they float in the watery solution. Some of the water molecules are integrated inside the balls too, helping them to swell and retain a bouncy structure, so that the uncooked white seems gluey and sticky.
When these proteins are subjected to stress – such as beating with a whisk or cooking – the balls move around quickly and bash into each other, as well as into the water molecules, and they unfold and become long wiggly chains. The delicate bonds that were holding the balls in shape have broken. In this unnaturally energetic environment, it is much easier for the long chains to stick to other long chains, resulting in more and more chains clumping together in a bunch. Soon an interconnected network of many different protein chains forms, and entraps some of the water, making the opaque, slippery, rubbery "cooked egg" structure that we are familiar with.
"Untangling" rather than "unboiling" - a longer version
Gregory Weiss (professor of chemistry, molecular biology and biochemistry) and his team at the University of California Irvine set about trying to find a way to untangle the massed protein chains in the semi-solid "white" and allow them to form loose balls again, making a clear jelly-like liquid resembling the uncooked egg. They knew this could not happen spontaneously just by cooling the white because of the laws of physics. So they devised a chemical and mechanical set of processes to gradually unwind the long strands and persuade them to go back to their original ball-shapes.
Simple – right? Simple in concept, as many good scientific principles are. Not so easy to prove the principle in practice, as is often the case.
For many years, there have been salts and nitrogenous chemicals such as urea used by biochemists to tease apart proteins from cells, so that they could study individual proteins. The team at UC Irvine persevered in modifying the temperature, the concentrations and the various "tried and true" chemicals known to gently disrupt the bonds holding proteins to surfaces. Eventually, by careful manipulation, they got the exact methodology right to tease apart the protein in the solid egg white.
Although the white dissolved, it still did not look like uncooked egg-whites. The proteins had broken up a bit too much into small pieces.
I am pleased to say there is an Australian connection here. Professor Colin Raston from Flinders University had developed a tiny little machine to do exactly what they needed to do – a "vortex fluid device" that was able to squeeze the small protein chains (they are too small to be seen under a microscope) and slide them over each other with just exactly the right amount of tension – not too much, not too little – so that they were forced together to make the delicate bonds to hold them in little balls again.
As Goldilocks said, it was "just right".
Applications
The scientists explain that manipulating proteins is a very useful skill to have in the medical, biological and food-processing industries. The egg was a cheap and convenient experimental tool – no-one in the kitchen would really want to unboil their egg!
Their methods for changing the protein structure without destroying the actual long chain may be important in recovering valuable waste protein material in research, or in making some processing of medicines more efficient (for example, antibodies for cancer treatment or some vaccines), or even in areas such as cheese-making. No-one can predict what other processes that involve some degree of biochemistry may be made more sustainable by using these methods once the patents have been granted and the processes made public.
Concluding with a little moral lesson:
If a headline or advertisement seems to be saying something that is too good to be true, then it probably is too good to be true (even if it purports to be scientific).
It is wise to read the article in full, and if you are still sceptical (as I was), to look up some of the original research or to ask a friendly scientist to explain the process.
In the meantime, I hope you enjoy your (cooked) eggs more in the future, knowing why they have that lovely structure. All this sounds a little like Salvation, it has a lovely structure!
Dr Mark Tronson is a Baptist minister (retired) who served as the Australian cricket team chaplain for 17 years (2000 ret) and established Life After Cricket in 2001. He was recognised by the Olympic Ministry Medal in 2009 presented by Carl Lewis Olympian of the Century. He mentors young writers and has written 24 books, and enjoys writing. He is married to Delma, with four adult children and grand-children.
Mark Tronson's archive of articles can be viewed at http://www.pressserviceinternational.org/mark-tronson.html
