The Triple Helix @ UChicago

Winter 2018

"The Chemistry of Cooking" by Edward Zhou

 

Humans have been cooking, quite literally, since the discovery of fire, when our ancestors realized that heat made certain foods both better tasting and easier to digest. We’ve come a long way since then. Recent advances in our understanding of chemistry and high-tech laboratory technology have been finding their way into the kitchens of America’s top restaurants, dispelling old cooking myths, turning cooks into scientists, and adding a whole new suite of tools for chefs to pursue cuisine that is ever more delicious. Here’s a sample of some cool cooking chemistry you can probably relate to.

Seal in the Juice?

If you’ve ever heard that searing meat “seals in the juices”, you’ve been hoodwinked by some old-time culinary wisdom that has simply not held up to 21st century scrutiny. To be fair, it does seem to make sense at first; searing the meat creates a crust, which certainly seems like it could be a barrier of sorts between your juicy medium steak and the hot pan it’s being cooked in. It hasn’t helped that world-renowned chefs have continued to say the same thing [1]. Unfortunately, the truth is that controlled tests have shown that no such retention of juices is actually observed. The reason that meats are actually seared is not to retain moisture, but rather to enhance flavor via a chemical process known as the Maillard reaction. First introduced by the French chemist Louis-Camille Maillard in 1912 in his studies of protein synthesis, the Maillard reaction is a form of caramelization involving amino acids and reducing sugars which takes place above around 150°C [1,2]. The amino acid which takes part in the reaction determines the final flavor — and hundreds of flavor compounds are created in the typical searing process. This gives a well-seared piece of meat its distinctive flavor. Now you know — the next time you bite into that perfect bite of steak, remember that color means flavor, and that no amount of searing will prevent a well-done cut from being about as juicy as sawdust.

Sriracha is the gateway to addiction... and masochism

If you’re a fan of spicy foods, that bottle of your favorite hot sauce can seem really hard to turn away. Why does spicy food keep us coming back, again and again, despite flaming mouths, sweating foreheads, and burning pain? As it turns out — spicy doesn’t just make you hurt — it simultaneously makes you happy, and the culprit is capsaicin. If you’re involved in the business of spicy eating, you’ve probably heard of capsaicin. Capsaicin and similar compounds, collectively known as capsaicinoids, are initially derived from vanillin and are responsible for what we perceive as spiciness. However, in addition to the perception of pain, the presence of capsaicinoids causes the brain to release dopamine — the neurotransmitter responsible for reward and pleasure [1]. This creates an addictive effect that follows much the same pathways as cocaine, which also triggers a surge of dopamine.  Sweet sriracha dreams! 

Zero-Calorie Sugar Water

Let’s face it. We know that it’s unhealthy for us, but come on, sugar just plain old tastes good. As a way to satisfy our sweet tooth without all the unhealthy calories, many foods and beverages make claims to have “no added sugar,” substituting things like sugar alcohols and artificial chemicals instead. But did you know that there’s another all-natural way to make water taste sweet? It’s nature’s answer to an artificial sweetener, known as cynarine, and it’s found most prominently in artichokes [1]. Rather than directly acting on our taste buds to trigger a sensation of sweetness, cynarine acts in the other direction —  suppressing taste receptors for sweetness and enhancing those for bitterness. When the cynarine is cleared away by subsequent foods or liquid, the unbinding of cynarine creates a powerful sweetness-perception effect that makes everything from water to salads taste inexplicably, incredibly sweet. How’s that for a cool dieting trick? [1].

Organic chemistry... in the kitchen

If you’ve ever had the misfortune of taking organic chemistry, you’ve definitely used a rotovap. But these ten-thousand-dollar machines, frequently bought on the cheap from busted biotechnology companies, have been finding their way into America’s top kitchens, where chefs use them to make intensely-flavored sauces and perform flavor extracts that were once technically impossible. Actually, rotary evaporators are a part of an entire new field of cooking called molecular gastronomy, which emphasizes science-focused techniques to make ultra-modern cuisine. Entire restaurants have sprung up around the concept, and, while rotary evaporators are seriously out of the price range for home cooks, a molecular gastronomy starter kit can now be easily found online for around 20 dollars, enabling you to turn fruit juice into boba balls, make see through pasta, and eat your ice cream steaming hot. It’s never been a better time to relive gen chem in your apartment every day, only more delicious.

And there you have it! Four fun facts from the budding world of food science — a reminder that things learned in class and work done in lab can have applicable — and delicious — results. 

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The Maillard reaction in action. (Courtesy and copyright of the author. Permission for use on the TTH blog only.)

 
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