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It’s Thanksgiving Day. You’ve cooked your enormous turkey for hours – hope it’s not dry! Your relatives have arrived with a parcel of kids (four? Five? They move too fast to count!) And Uncle Joe is already at least two glasses of wine down.
But it could be much worse. Imagine all that: but instead of buttery mashed potatoes and hot gravy, you’re chewing on a whole, raw potato and some glistening fat. Unappetizing, right?
Raw potato. Mmmm, yummy! (Image used with permission from Pixabay (CC0))
Cooking is what turns your Thanksgiving dinner into more than just a pile of ingredients. It’s been around for a long time – maybe even two million years.[i] And it’s made possible by chemistry: heating denatures proteins and kills harmful bacteria, while chemical reactions between ingredients can actually create new flavors.
The Maillard Reaction
One of the most important chemical reactions in cooking is called the Maillard reaction. No, it’s not named after a duck – it was first described by Louise-Camille Maillard, a French chemist.[ii] The Maillard reaction is actually one of the most important elements to your Thanksgiving dinner, even more important than Grandma’s secret pumpkin pie recipe.[iii] Without it, no toasted dinner rolls, no roasted turkey, and worst of all, no beer.
The Maillard reaction occurs between two different molecules: amino acids and sugars. Amino acids pop up in biology all the time, since they’re the building blocks of proteins, while sugars serve as our main source of energy.
When heated between 140 and 160 Celsius,[iv] the sugar – which must contain a double-bonded oxygen atom – reacts with the eponymous amino group of the amino acid. (An amino group is just a fancy name for a nitrogen atom bonded to three other molecules). This reaction produces a whole host of different flavor molecules, determined by what kinds of amino acids and sugars were in your ingredients to start with.
Made possible by the Maillard reaction. (Image used with permission from Pixabay (CC0)).
So what kinds of foods undergo the Maillard reaction? It gives browned foods their distinctive flavor, from the golden-brown crust of fresh bread to the malted barley in your beer.[v] Roasted meats also undergo Maillard browning.[vi] Just don’t turn the burner up too high: heating your amino acid and sugar too much could produce a molecule called acrylamide, which might be a carcinogen.[vii]
The holidays are tough for everyone – but at least the food is amazing. If Thanksgiving Dinner has got you stressed, just remember that science has your back. Whip out your chemistry skills and the mashed potatoes are sure to turn out perfectly. If everything else fails, when your second cousin says something atrocious: just start talking about the Maillard reaction. That should quiet the room nicely! Thanks, #Science.
By Kristina Vrouwenvelder
[i] https://doi.org/10.1073%2Fpnas.1107806108
[ii] Maillard, L. C. (1912). “Action des acides amines sur les sucres; formation de melanoidines par voie méthodique (Action of Amino Acids on Sugars. Formation of Melanoidins in a Methodical Way)”. Compt. Rend. 154: 66.
[iii] https://pubs.rsc.org/en/Content/eBook/978-0-85404-964-6
[iv] https://www.tastingtable.com/cook/national/why-bake-350-degrees
[v] https://www.popsci.com/science/article/2012-12/beersci-how-beer-gets-its-color
[vi] McGee, Harold (2004). On Food and Cooking: The Science and Lore of the Kitchen. New York: Scribner. pp. 778–9. ISBN 978-0-684-80001-1.
[vii] Tareke, E.; Rydberg, P.; Karlsson, Patrik; Eriksson, Sune; Törnqvist, Margareta (2002). “Analysis of acrylamide, a carcinogen formed in heated foodstuffs”. J. Agric. Food Chem. 50 (17): 4998–5006. doi:10.1021/jf020302f. PMID 12166997.
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