“Cooking isn’t an exact science,” you often hear chefs say. “It’s a passion.”
I beg to differ. Cooking is a very exact science. In fact, exact sciences can be used to explain one of the most common things food does: brown.
There are, in my opinion, 3 main ways food tends to turn a brown color.
- The brown you see when cooking a steak.
- The brown you see when making syrup.
- The brown you see when you leave a cut apple out on the counter for too long.
The third is by far the most tragic, so let’s get the worst over with: enzymic browning.
Enzymic browning is the browning seen in fruit, like apples or bananas, when cut.
Fruits (like apples) contain things called phenolic compounds, which contribute to the aroma/flavor of the fruit. Fruits also contain enzymes.
Basically, what happens is that those enzymes catalyze a process called oxidation, where the plant cells are damaged and become exposed to oxygen. Oxidation turns the phenolic compounds to quinone compounds, which cause the fruit to appear brown.
This process can be stopped by either keeping the oxygen from being exposed to the broken cells (aka Mom’s cling film method) or by applying a strong acid (aka lemon juice or whatever) to the damaged cells so as to slow down the work of the enzymes.
Now, you can eat not-brown yummy fruits whenever (and impress your chem teacher?)
Caramelization is the process of sugar being heated and becoming brown. But why?
(I looked it up so you don’t have to.)
When sugar is heated, a number of chemical reactions form. Polymers, for example caramelans, caramelens, and caramelins (I had a good laugh realizing they’re pronounced almost all the same), are formed and help create the characteristic brown flavor, while the breakdown of sugars make your food taste sweeter.
Sugars, the star of this process, are also actually molecules that are carbon-based, meaning they’ve got carbons hiding in their structures. Heat does a pretty good job at breaking those bonds between the atoms.
What do we know about carbon? We know it’s black.
So when the sugars (usually complex sugars) are broken down into more simple sugars, carbon is also released, helping to make your syrup––candy?––appear more brown.
Note: If you overdo it, the sugars will break down completely and you’ll have a mess. Don’t do that.
3. The Maillard Reaction
Now, across the internet, this reaction has been called probably the most fantastic chemical reaction to exist in cooking. Ever.
Imagine this: there’s a juicy steak in front of you, seared to perfection, the brown crust glistening as meat juice oozes out of it with the first slice. You take a bite. It’s full of meaty, nutty flavors. Umami. Happiness.
I’m drooling a little bit.
For those of you interested in the specifics, keep reading. If you want a Sparknotes-friendly version, scroll until you see the steak photo.
The Maillard reaction happens in three distinct steps.
- The amino group on an amino acid or a protein reacts with the carbonyl group of a sugar molecule, forming glycosylamine.
- The glycosylamine undergoes isomerization via Amadori rearrangement to form the Amadori compound ketosamine.
- The ketosamine reacts to produce one of 1000+ possible product molecules which all have different flavor profiles, contribute to browning, and can even react further in some cases.
You’re here for the simplified version. I get it. Not all of us have the time or mental energy to try to understand chemistry. (I was allergic to it in high school. I feel the struggle.)
The rundown is: (Sugars + Protein) + heat = browning + flavor!
What’s important to note is that some products of the Maillard reaction are known/possible carcinogens, so just try not to char anything too badly.
And there you have it!
I hope this post was informational (and somewhat fun to read), so that maybe at your next dinner party you can bust out the science and wow your guests.
Until next time!
P.S. This post was created with a bunch of research––courtesy of the internet machine––on my part, but if anything is wrong, please let me know!