How to unboil an egg - Eleanor Nelsen

Summary

This video explores the fascinating concept of unboiling an egg, a process once thought impossible. By using mechanical energy and a chemical solution, scientists can reverse the denaturing of proteins in egg whites, returning them to their original state. This method, which involves spinning the solution at high speeds, could revolutionize the production of pharmaceutical proteins, making them cheaper and faster to produce. The video also explains the limitations of this process and the difference between simple boiling and more complex cooking methods like frying, which involve irreversible chemical changes.

Takeaways

• 😀 Thermal energy denatures egg proteins, causing them to unfold and form a solid mass when boiled.
• 😀 Mechanical energy, such as spinning, can reverse the process of denaturation to 'unboil' an egg.
• 😀 Eggs are mostly made of water and proteins, which are initially folded into intricate shapes held together by weak chemical bonds.
• 😀 Denaturation is the process by which proteins lose their folded structure due to heat, resulting in them becoming tangled and solidified.
• 😀 According to the principle of microscopic reversibility, processes like protein denaturation can theoretically be undone.
• 😀 The key to reversing denaturation in egg whites is spinning them in a centrifuge at extremely high speeds (5000 rpm), creating sheer stresses that help proteins return to their original shape.
• 😀 Urea, a small molecule, is used to dissolve the boiled egg whites and make it easier for proteins to slide past each other during the spinning process.
• 😀 This spinning technique can work with other proteins, and even large proteins can be refolded using a plastic bead to apply extra stress.
• 😀 This method of 'unboiling' an egg is not applicable to a whole egg in its shell due to the need for the solution to spread evenly in a cylindrical chamber.
• 😀 The unboiling technique has significant potential in pharmaceutical production, as it can help refold expensive and tangled proteins for drug production.
• 😀 Unlike egg boiling, many cooking processes, such as the Maillard reaction, involve irreversible chemical changes that cannot be undone, such as when frying or caramelizing foods.

Q & A

What happens to the proteins in an egg when heat is applied?

When heat is applied to an egg, the proteins in the egg unfold, uncoil, and unwind. This process, called denaturing, disrupts the weak chemical bonds holding the proteins together.

What is denaturing in the context of cooking an egg?

Denaturing is the process where proteins in the egg unfold and lose their natural structure due to the heat, causing them to bond with neighboring proteins and form a solid mass, like in a boiled egg.

Can you unboil an egg, and if so, how?

Yes, it is possible to unboil an egg, at least the egg whites. This can be done by dissolving the boiled egg whites in a solution with urea, then spinning the solution at a very high speed in a centrifuge to cause the proteins to return to their original shapes.

Why can't you unboil a whole egg?

A whole egg cannot be unboiled because the unboiling technique requires the solution to spread throughout a cylindrical chamber. The whole egg, with its shell intact, would not allow for this process to work.

What role does urea play in unboiling an egg?

Urea acts as a lubricant that coats the proteins, making it easier for them to glide past each other during the spinning process in the centrifuge. This helps the proteins return to their native shapes.

What scientific principle allows for the unboiling of an egg?

The principle of microscopic reversibility suggests that anything that happens can theoretically unhappen if the process is reversed. In the case of unboiling an egg, this means the denatured proteins can be returned to their original form by reversing the mechanical process.

How does the centrifuge help in unboiling the egg whites?

The centrifuge spins the egg white solution at 5000 rotations per minute. This spinning creates sheer stresses that stretch and contract the proteins repeatedly, eventually causing them to snap back into their original folded shapes.

How can this unboiling technique be applied beyond just eggs?

This technique can be applied to refold proteins in pharmaceuticals. Many proteins in drugs are expensive to produce due to the difficulty in untangling their misfolded forms, but this spinning method may offer a cheaper, quicker, and more efficient way to refold them.

Why is boiling an egg considered an unusual cooking process?

Boiling an egg is unusual because, although it changes the shape and structure of proteins, it doesn't change their chemical identity. Unlike many other cooking processes, boiling doesn't cause a chemical reaction like the Maillard reaction, which alters the chemical makeup of food.

What is the Maillard reaction, and how does it differ from boiling an egg?

The Maillard reaction is a chemical reaction between sugars and proteins that creates new flavors and brown coloring, such as in caramelization. Unlike boiling an egg, the Maillard reaction results in irreversible chemical changes that are much harder to undo.