UR-chemistry

You might not be an undergrad anymore, but you can still give learning the old college try. At the University of Richmond, Kristine Nolin, Ph.D., teaches a course called "The Chemistry of Cooking and Modernist Cuisine." We asked for some insight.

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Tell us about a food that takes on great variation through chemistry.

A steak is a great example. Everyone can agree that the smell, feel – and taste – of a raw steak is very different from one that was grilled.

As heat is applied, the chemical structure of the food changes by way of different reactions. These chemical reactions will break down the large proteins and form the small, lightweight molecules that are trapped in your mouth or nose, resulting in the experience of flavor and scent.

For us lousy cooks, is there a scientific principle atop the you-should-know list?

Heat transfer. Heat is a form of energy, and it's always moving from areas of high heat to low heat. After food is removed from a heat source, the internal heat will move around until it is evenly distributed.

This is one reason that cooking that perfect, medium-rare steak is so difficult. The heat is absorbed on the outside of the steak and transferred toward the middle.

So if you take your steak off the grill just as it reaches your desired doneness, it will be well-done very quickly. The energy keeps moving toward the center and cooks the meat.

Is there a favorite exercise you use with students?

In one experiment, we make chocolate lava cakes to compare the efficiency of heat transfer under dry versus moist conditions.

The students make six small lava cakes and bake them using either dry or moist heat. At regular intervals, a cake is removed from the heat, the internal temperature is measured at different positions, and the width of the cooked portion of the cake is assessed.

Spoiler alert: The moist heat works much better!

What is one of the most complex foods?

Ice cream. It is amazingly complex!

I remember being young and melting a bowl of ice cream and trying to refreeze it. I was completely baffled that the ice cream was never the same.

Ice cream is a complex mixture of air bubbles, ice crystals, milk proteins and milk fat globules in a sugar solution. The perfect mixture of molecules with different properties allow for these solids, liquids and gases to exist as ice cream.

How has chemistry changed the culinary industry?

Chemistry, as well as biology and physics, have all greatly influenced the industry. The molecular gastronomy movement is fully based in the understanding of the science behind the structure, properties and reactivity of food molecules.

Gotta ask: As a chemist, are you a decent cook?

Absolutely not – which is why I married a chef! I work in the world of exact measurements, times, temperature, etc. Nothing will break me out in a cold sweat faster than being told to add a pinch of this or a dash of that.

That being said, as a chemist, I do consider myself a skilled baker.

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Kristine Nolin is an associate professor of chemistry in the University of Richmond's School of Arts & Sciences.

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