Onions are some of the strangest food items on the planet. When uncooked, an onions is something that you rarely want any part of. Bitter and tart, the occasional exception is a sliver or two added to a hamburger or sandwich. However, when onions are cooked, they become a whole different animal. They get softer, sweeter, and just overall a much better vibe. Heck, you can even eat them on their own, which can’t be said about them when they’re uncooked. Here’s why that’s the case, and what happens when onions are cooked.
Sulfur
Onions are filled with sulfur compounds, and it’s these compounds that contribute to the raw and bitter flavor. In fact, it’s these compounds that are released when you cut into an onion, and why you may start to cry as a result.
Caramelization
However, something interesting happens when you start to expose an uncooked onion to intense heat. A series of chemical reactions begin to occur, and it particularly affects the sugars within the onion. Before cooking, the sugars within the onion are natural and not very palatable—but the heat allows the internal raw sugars to caramelize and thus become sweeter and more delicious.
The Maillard Reaction
Another thing that happens upon onions being cooked is what’s known as the Maillard reaction, which is basically amino acids combining with the newly caramelized sugars. This adds a rich flavor to the onions which didn’t exist before, further rounding it out into a delicious edible creation.
