Rise and caramelize
Chemistry is perhaps most famously exploited in creating desserts and breads. Chemical processes can be seen in rising dough, caramelizing sugar, flambéing boozy desserts—the list goes on.
Sharma has always had a sweet tooth, and while making the transition from medical researcher to chef, he spent two weeks moonlighting at a patisserie. There he learned scientific culinary techniques, like emulsification, that continue to intrigue him. “The lecithin that’s in egg yolk is fascinating,” he says. “Just to see how it interacts with air, with fats around it. It can actually build what is essentially a mesh when it bakes in the oven.”
Homemade ice cream is a favorite in Sharma’s dessert repertoire. “If you’re using egg yolk, you want the amylase enzyme inside the yolk to break down; that’s why you have to reach a certain temperature,” he explains.
Molecules in eggs give rise to sweet treats.
That Rising Feeling
Batter rises thanks to leavening, a reaction that gives cakes and cookies volume, form, and texture.
Beating eggs into dough introduces air bubbles into the batter. Meanwhile, water in the batter, when heated in the oven, converts to steam. When the air bubbles interact with the steam, the bubbles expand, causing the batter to rise.
Protein-protected air bubbles
In their natural state, egg-protein chains are coiled up and held together by weak peptide bonds. Beating eggs agitates the chains, forcing them to unfold, while the bonds between the chains start to break.
A foam forms as the unfolded proteins interact with each other, trapping air between them. When the uncoiled proteins come in contact with the air, hydrophobic parts of the chains move toward the air and the water in the batter.
As the chains rearrange themselves, new bonds form between them, creating a protein network around the air bubbles. As the network meets heat, it solidifies to protect the air bubbles and keep cakes, cookies, and muffins airy and fluffy.
Whipping up a foam
Whipping egg whites aerates them, producing meringues' characteristic foam. This cloud-like quality is created by the protective network of proteins that form around the air bubbles.
Only egg whites are used in meringue-making, since yolks contain emulsifying fats that inhibit foaming.
Proteins in egg white also prevent meringues and other desserts from collapsing as they leave the oven. As the meringues bake, the proteins coagulate, resulting in a semi-solid web of egg-white protein that keeps its form even when the air bubbles burst.
Let's Stick Together
Fats and water do not mix naturally. Emulsifiers, though, help them bind together—and eggs are excellent emulsifiers. Lecithin is one of the most important emulsifiers found in egg yolk, its hydrophilic ends attracted to water and fastening to fat. Lecithin, therefore, can hold fat and water together.
Thanks to the emulsifying action of eggs, deserts like cake, mousse, and ice cream get their smooth, velvety texture.
But chemistry is a delicate balancing act, so bad timing and incorrect measurements produce unwanted results: Your bread will flop; your meringue will collapse.
This problem is compounded when riding 129 km/hour on train tracks. Just ask Hans Plugge, a self-taught volunteer chef on the private railroad car Dover Harbor. (For full-time work, Plugge is a senior toxicologist at Verisk 3E, a provider of chemical, regulatory, and compliance information services.) Plugge cooks from scratch for passengers on short hops from Washington, D.C., to Williamsburg, Va., as well as on longer trips to places like Chicago and New Orleans. Along with other chefs working to recreate the golden era of railway travel, Plugge also hosts the annual dining extravaganza Chef’s Table, during which eight courses are prepared and served on the railroad car.
“When you’re trying to make desserts especially, there’s definitely chemistry involved in getting things to set,” Plugge explains. This includes altering the amounts of gelling agents used to account for train movement. So, for panna cotta, a molded Italian dessert, “we tend to make them a little stiffer; otherwise, the movement of the car will cause waves,” he says.
A recipe for understanding
Plugge and Sharma share the distinction of being both scientists and masters of the culinary arts. Talking about the parallels between the two, Sharma becomes animated. One of the greatest links, he says, is an inquiring mind. “I’m always curious; I’m always thirsty to understand.”
But there are also more concrete connections. Think of adding salt or sugar as an abrasive when grinding ingredients, says Sharma, recalling how he used magnetic beads to break down cells during medical research. “That was essentially the same thing,” he says. “But those magnetic beads are banging against the cells and rupturing the membrane.”
The blender, too, can work double duty, as both a chef’s appliance and a chemist’s tool. Sharma remembers using a heavy-duty blender to smash apart tissue and extract proteins in the laboratory. Nowadays, he does the same thing in his kitchen, but the results, which include mint-and-garam-masala burgers and peppermint marshmallows, sound far tastier.
CORRECTION: This story was updated on Jan. 14, 2019, to correct the ingredient that turns turmeric red. It is baking soda, not lemon juice, as originally stated in the story.