Every Wednesday, 14 first-years head to a kitchen to conduct “edible experiments” that help them see how chemistry applies to cooking. The lab is part of a new first-year seminar, CHEM 0080F: “Kitchen Chemistry,” taught by Associate Professor of Chemistry Sarah Delaney.
Potatoes ‘are not all the same’
The class consists of two parts — Monday’s seminar portion, in which Delaney explains scientific concepts, and Wednesday’s lab section, in which students cook and eat.
This week’s seminar focused on why humans perceive certain tastes as “sweet,” how pH levels affect the way potatoes cook and why different potato varieties have different textures when cooked.
Delaney said people have certain taste receptors on their tongues that allow them to detect sweetness, adding that individual glucose molecules trigger those receptors, while chains of the same molecule — starches — do not. This is why potatoes, which contain starch, do not taste sweet, while foods containing glucose do.
Delaney also talked about the phenomenon of miracle berries. These berries contain a protein that attaches to the sweet receptor, altering it so that it only functions in conditions of low pH when people eat something very acidic. For example, after eating miracle berries, “you can just drink vinegar” because it will taste sweet, she added.
Delaney also discussed the differences among potatoes, which “are not all the same,” she said, adding that once cooked, some potatoes have a more “mealy” texture while others have a more “waxy” texture. The chemistry behind these differences lies in the types and amounts of starches present in the potatoes, she said.
Though Delaney taught about the differences between potatoes in a lecture, she kept the class interactive, even on a non-lab day. She set out containers of three different kinds of potatoes and had the class sample them, asking for their reactions to the textures. She then explained how the potatoes varied in their starch content, allowing the students to directly experience the effect of chemistry on the results of cooking.
In this week’s lab, students will make home fries and potato salad to investigate another concept — the way pH conditions affect how a potato cooks. Potatoes contain pectin, which functions as a sort of “glue” that holds the potatoes together, Delaney said, adding that this glue works best under acidic conditions, or when the potatoes cook in a low-pH environment.
The students will cook the potato salad under acidic conditions, so that the pectin will act like glue and the potatoes will remain “intact,” Delaney said in class.
But then students will cook the home fries in a high-pH, or basic, environment so that the pectin will break down, making the potatoes mushy, Delaney said. The softening of the potatoes will increase their surface area, making it easier to evaporate the water in them and giving them the crispy texture characteristic of home fries, she added.
Inspired teachers
Students in the course raved about the instructor.
“We’re really lucky because we have Professor Delaney. She’s an amazing teacher … and it comes through in what she does,” said Taylor Viggiano ’17.
Delaney said she wanted to teach a “broad-interest” class that would appeal to non-chemistry concentrators. “I thought that combining chemistry with food and cooking would be a way of having a topic that would be interesting to people,” she said.
The course is currently offered only to first-year students simply because the kitchen has a limited capacity, Delaney said. But many upperclassmen were also interested in the course, so Delaney said she hopes to expand its capacity in future years.
Iyad Owen-Elia ’16 said he saw the course description in Banner last spring and was disappointed that it was not open to upperclassmen, so he emailed Delaney and secured a position as the teaching assistant.
As the TA, Owen-Elia helped Delaney design the course’s curriculum. Currently, he “oversees” the kitchen experiments, he said, making sure all goes well, and he helps to explain the overlap between chemistry and cooking.
Interdisciplinary love
Delaney said she created the course to fuse her passion for cooking with her academic career.
“I always enjoyed cooking, and the more you learn about science, the more you realize that it applies to cooking,” Delaney said. “Cooking is an applied science, and a lot of that science is chemistry.”
Owen-Elia also expressed excitement for both science and cooking. “I love cooking and have loved it for a long time,” he said. “I’m really interested in how science and cooking intersect because in school I mainly do science, but out of school my main passion is cooking. And this class seemed like a chance to combine those.”
Students also showed enthusiasm for both elements of the course.
“I’m also really into food so I love learning the concepts behind it, and why fish changes color as it cooks and how the proteins are denatured and that kind of thing,” Viggiano said.
Marley Rafson ’17 said the class provides “a unique glance at chemistry. … (It) shows you that chemistry can be fun.” She said her “favorite part of the class is that you get to eat at the end of the lab.”
Viggiano said she believes the class is improving her skills as a chef, and Owen-Elia seemed to share Viggiano’s sentiment. “I think that a knowledge of science and an understanding of the chemistry of what’s going on in food can really allow a cook to execute their ideas much more effectively and to achieve really cool dishes that maybe wouldn’t be possible without that knowledge,” he said.
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