Coagulation to Caramelization: How Heat Affects Food
We all know that most food preparation involves heating the food, whether by roasting, baking, grilling, frying, or searing. We know that during the cooking process, red meat gets brown, liquids become solid, and flavors change. But have you ever wondered why that is? In order to help you better understand the cooking process, we’ve explained the basics of why food reacts the way it does when it’s heated up.
Plant- and animal-based foods are made up of long molocules called proteins. When they’re heated, the proteins break up and lose moisture. This makes them change from a liquid (or semi-liquid) to a solid in a process called coagulation in food.
Temperature this starts at: 140 degrees F
Examples: hard boiled or fried eggs
When starches are heated, they absorb liquids around them. This makes solid starchy foods softer. Starches can also be added to foods like soups and stews that are mostly liquid for thickening purposes. The whole process is known as gelatinization.
Temperature this starts at: 150 degrees F
Examples: pasta and rice getting larger and softer after boiling, flour thickening a soup
Heated sugar tends to turn brown and change flavor. This not only applies to the sugar we actively add to foods, like baked goods or desserts, but to the naturally-occurring sugars in foods, as well. This process, known as caramelization, is responsible for the majority of flavors we associate with cooking. Since this happens at a higher temperature than water boiling, it also explains why foods only brown if prepared with dry heat methods.
Temperature this starts at: 338 degrees F
Examples: brown top of a creme brulee, bread turning brown as it bakes
This is the process most people are probably familiar with from science class. When water is heated, the molecules move faster and faster until they turn into a gas (steam) and evaporate. Because water is in so many foods, this explains why foods get more dried out when they’re cooked.
Temperature this starts at: 212 degrees F
Examples: water boiling, spinach losing shape
Unlike water, fats won’t evaporate when heated, though they do melt. At room temperature they can be solid, liquid, or somewhere in between, but all of them become liquid when heat is applied to them. Because it takes much higher temperatures to burn foods that fit in this category, they’re often used as a medium to cook foods, rather than just as an ingredient.
Temperature this starts at: varies depending on fat
Examples: using butter or oil to pan-fry
As you can see, there are a lot of different scientific reactions that happen to your ingredients when you throw them on the stove or put them in the oven. One or more of these reactions can be happening at the same time in order to give you the results you want. So, the next time your food isn’t cooking perfectly, think about how you can adjust the amount heat you’re using to cook it with.