---
title: "Denaturation: what it means in cooking — Tiny Plates"
description: "Denaturation is when heat, acid, salt or whisking makes proteins unfold and change shape. It is why eggs set, meat firms up and egg whites whip into foam."
url: "https://www.tinyplates.dev/glossary/denaturation"
---

# Denaturation

Denaturation is when heat, acid, salt or whisking makes proteins unfold and change shape. It is why eggs set, meat firms up and egg whites whip into foam.

Also called Denature, Protein denaturation.

Denaturation is what happens when a protein loses its natural folded shape. Proteins in food start as tightly folded chains. Heat, acid, salt, alcohol, air and even whisking can make them unfold. Once unfolded, they often stick to each other. That is why a clear egg white turns white and firm, raw fish turns opaque in lime juice, and meat shrinks and firms as it cooks.

## Why it works

Unfolded proteins expose parts that were hidden inside the fold. These parts bond with nearby proteins and form a network that traps water. A loose network gives a soft set, as in custard or a [coddled](https://www.tinyplates.dev/glossary/coddle) egg. A tight network squeezes water out, as in a rubbery overcooked egg, dry meat or [curdled](https://www.tinyplates.dev/glossary/curdle) sauce.

Different proteins unfold at different temperatures. Egg white starts to set at about 62°C (144°F) and is firm by about 80°C (176°F). Yolk thickens from about 65°C (149°F) and sets around 70°C (158°F). Muscle proteins in meat start changing from about 50°C (122°F), which is why a steak changes texture so much between rare and well done.

## How to use it

* **Heat**: cook eggs gently for a tender set, and pull meat at the right internal temperature.
* **Acid**: in [ceviche](https://www.tinyplates.dev/glossary/ceviche), lime juice denatures the outer protein of fish so it turns opaque and firm. It looks cooked but has not been heated, so it does not kill bacteria or parasites the way cooking does.
* **Salt**: a [brine](https://www.tinyplates.dev/glossary/brine) partly unfolds muscle proteins so they hold more water.
* **Whisking**: beating egg whites unfolds their proteins at the surface of air bubbles, which builds a stable foam that can reach [stiff peaks](https://www.tinyplates.dev/glossary/stiff-peaks).

## Common mistakes

* Thinking denaturation and food safety are the same thing. Acid or salt changes texture but does not make raw food safe.
* Cooking eggs or lean meat too hot, so the proteins squeeze out their water.
* Adding acid or salt to milk proteins carelessly, which can make them clump.

## In recipes

Recipes rarely use the word. You see its effects in "cook until the egg whites are set", "until the shrimp turn pink and opaque" and "until the fish flakes".

## Related terms

* [CurdleCurdling is when milk, cream or egg sauces separate into lumps and thin liquid. It happens from too much heat or acid. Here is how to stop and fix it.](https://www.tinyplates.dev/glossary/curdle)
* [CoddleTo coddle is to cook food, usually eggs, gently in water just below a simmer. Coddled eggs have barely set whites and runny yolks, softer than soft-boiled.](https://www.tinyplates.dev/glossary/coddle)
* [CevicheCeviche is raw fish firmed up in lime juice with onion, chili and cilantro. See how long to marinate it, which fish to use, and why acid is not heat.](https://www.tinyplates.dev/glossary/ceviche)
* [BrineA brine is salt dissolved in water. Soaking meat in it for hours makes it juicier and seasons it through. Here are the ratios, times and safety rules.](https://www.tinyplates.dev/glossary/brine)
* [Stiff peaksStiff peaks are when whipped egg whites or cream stand straight up off the whisk without bending. Here is how to reach the stage without overwhipping.](https://www.tinyplates.dev/glossary/stiff-peaks)
* [CollagenCollagen is the tough protein in meat's connective tissue. Slow, moist cooking turns it into gelatin, which makes braised meat tender and stock set.](https://www.tinyplates.dev/glossary/collagen)

[More in kitchen science](https://www.tinyplates.dev/glossary/category/kitchen-science)[Every term from A to Z](https://www.tinyplates.dev/glossary)