Chemistry, or the study of how substances react, is often viewed as an intimidating subject, but it does not have to be. With so many complex concepts to memorize, formulas to learn, and abstract thinking required, it truly is one of the most difficult classes. However, it is worth the effort for a better ability to understand how our world works and why, all the way down to the tiniest scale.
After hearing the rumors about how difficult AP Chemistry was, I lacked confidence in my abilities at the start of the school year. To my surprise, I got a 5 out of 5 on the AP exam in June. This was the result of countless hours of hard work, but also good teachers, who helped me believe in myself. I actually have fond memories of studying for the AP Chemistry exam, although it is a stressful time for most, because I leaned into my existing interest in the topic. Learning is a more positive experience when viewed as discovery rather than a chore.
Applying chemistry knowledge to everyday objects and phenomena is a great way to overcome your fears about the subject, and a great way to deepen your understanding. It is not nearly as daunting when you can use chemistry to explain seemingly simple, commonplace parts of your surroundings. By making connections with your real world life, you can memorize concepts more easily. Take, for example, marshmallows. The four main ingredients are gelatin, air, corn syrup, and sugar. Utilizing chemistry and food science, they are designed to have a specific flavor and texture that makes them beloved worldwide.
Richard Hartel, a food engineer at the University of Wisconsin-Madison, describes marshmallows as “foam that’s stabilized by gelatin,” (Boerner). Gelatin is made of collagen, the main material that connects animal tissues. The first step is alkaline or acid treatment. Collagen is extracted and broken down into smaller protein molecules. The resulting gelatin is then purified, and afterwards added to warm water for heating. The spongy texture comes from air bubbles created while the gelatin cools.
Figure 1. Timeline created by Kaitlin Wong, featuring “Peep-o-Rama” from Minerva Public Library, www.minerva.lib.oh.us/content/peep-o-rama-0 and “Gelatin” from Nutrition by Nature, www.nutritionbynature.com.au/blog/gelatin-coconut-water-jellies.
When the gelatin is heated, it partially unravels the collagen helices. Gelatin strands spread out and take on elastic qualities, allowing easy conversion between liquid and gel. This is called a thermo-reversible gel, meaning it is liquid when heat is applied and the strands unravel, but gel when cooled, as the strands are twined back. This is depicted in Figure 2 below. The melting point is slightly higher than body temperature, which is why marshmallows can melt so perfectly in your mouth.
Figure 2. Source: Ludwig, Will. “Collagen.” C&EN, www.cen.acs.org/food/food-science/s-marshmallows-ingredients-work-together/99/web/2021/04
Air makes up more than 50% of a marshmallow’s volume. When the gel has passed its melting point but has not yet solidified, air is whipped in and the gelatin clings to it. This results in a 3D polymer, as shown in Figure 3, is a repeating sequence of monomers that make up a larger molecule, giving marshmallows a light, fluffy texture.
Figure 3. Source: “Polymers: from DNA to Rubber Ducks.” Curious, 19 Sept. 2019, www.science.org.au/curious/everything-else/polymers.
Last but not least, the final component is sweetness. Corn syrup and sugar combine in specific ratios to provide the perfect taste and texture. Sugar, or C6H12O6, consists of linked glucose and fructose molecules. Corn syrup, on the other hand, has the ability to prevent the sugar from crystallizing, through its mix of dextrin, dextrose, and maltose sugars in water. With less corn syrup and more sugar, crystals are formed that make candies more brittle. Gummy bears and marshmallows are preferred to be fluffy and soft, and therefore require a higher ratio of corn syrup to sugar.
Let’s review what we’ve learned: Gelatin provides the structure for marshmallows, the added air causes its fluffy texture, and a precise balance of sweeteners produces a desirable taste. So, when enjoying some marshmallows in a cup of hot chocolate, or opening a bag of gummy bears to share, consider the value of chemistry in the production of these scrumptious sweets!
Want to learn more about chemistry? Enrollment is still open to 9th and 10th graders for a free chemistry course from Creative Minds. Take the class to get a head start before taking an AP course, or just for fun to explore the fascinating subject. Sign up at https://www.creativemindsot.org/services-courses!
Sources
Becker, Rachel. “The Science behind a Perfectly-Toasted Marshmallow.” The Verge, The Verge,
11 June 2017, www.theverge.com/2017/6/11/15774634/marshmallows-smores-camping-
camp-fire-summer-food-science
Boerner, Leigh Krietsch. “What’s in marshmallows, and how do the ingredients work together to
make ooey-gooey treats?” Chemical & Engineering News, 2 Apr. 2019,
www.cen.acs.org/food/food-science/s-marshmallows-ingredients-work-together/99/web/ 2021/04
Moore et al. “3.10.2: Foods- Energy in a Marshmallow.” Chemistry LibreTexts, Libretexts, 5
Nov. 2020, www.chem.libretexts.org/Bookshelves/General_Chemistry/Book:_Chem
PRIME_(Moore_et_al.)/03:_Using_Chemical_Equations_in_Calculations/3.10:_
Standard_Enthalpies_of_Formation/3.10.02:_Foods-_Energy_in_a_Marshmallow.
Science Buddies. “Sweet Science: Making Marshmallows.” Scientific American, Scientific
American, 20 Dec. 2012, www.scientificamerican.com/article/bring-science-home-
marshmallows/
Pictures/Graphics
“Gelatin.” Nutrition by Nature, www.nutritionbynature.com.au/blog/gelatin-coconut-water-jellies
Ludwig, Will. “Collagen.” C&EN,
“Peep-o-Rama.” Minerva Public Library, www.minerva.lib.oh.us/content/peep-o-rama-0
“Polymers: from DNA to Rubber Ducks.” Curious, 19 Sept. 2019, www.science.org.au/curious/everything-else/polymers
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