Steak, cake and brown sludge!

Almost every day I walk past the back of a bakery and I’m tempted by the delicious aromas of freshly baked goods. Sometimes I give in. I love baked foods and I love baking. But it has always seemed like a bit of a dark art to me. You put a soggy mess into the oven and out comes something delicious. As it turns out, chemistry has an awful lot to do with it. One reaction in particular, which was discovered over one hundred years ago, is responsible for the whole variety of aromas which lure me through the bakery door.

Brown sludge and powdered eggs...

The story of this chemical reaction takes us on a journey through the 20th Century, back to France, 1912, when chemist Louis-Camille Maillard was trying to imitate in the lab how the body makes the proteins it needs to live and grow. Maillard noticed that instead of reacting as he expected, the sugars and amino acids which he had mixed together slowly turned into a brown sludge.

Brown sludge, politely called melanoidin, unsurprisingly failed to capture many scientists’ interest, and the Maillard reaction, as it is called, remained unstudied for several decades.

However the Second World War revived interest in the reaction when it was noticed that processed foods eaten by the troops, such as powdered eggs and tinned food, would slowly turn brown and taste unpalatable. Once they had worked out that it was the same reaction which had made brown sludge in the lab, scientists focussed on how to stop the Maillard reaction from happening at all. It seems strange that the same reaction which makes the crust on a nice bread roll so delicious is the same reaction which can make some foods taste bad.

It wasn’t until 1953, when an African-American scientist, John Hodge, put together all of the pieces of the puzzle, that we really understood exactly what was going on. During the process, which works best between 140 and 165˚C, amino acids, the building blocks of proteins, react with sugars. Both of these types of chemicals are found in almost all types of food, in an abundance of variety. When this reaction occurs, hundreds or even thousands of products can be formed, each depending on the amino acid which they came from. These contribute to the aromas and flavours of foods such as meat, popcorn, caramel, cake, onions, chocolate, bread...

...Basically, if it is brown, the Maillard reaction probably had something to do with it!

Nowadays scientists aren’t just interested in stopping the Maillard reaction when it makes food taste bad, but they also try to control it to create certain flavours and aromas. In fact every time we cook we are using this reaction, even if you’ve only ever just made toast.

I’m not sure if knowing about the Maillard reaction will help me to resist what’s on offer at the bakery, but maybe next time I’ll at least pause for thought before wolfing down a tasty treat.