A Consumer Chemistry Project by Kelsey Popcorn A Consumer Chemistry Project by Kelsey

The Chemistry of Popcorn Popcorn is a delicious treat, enjoyed by individuals worldwide. My research project investigates the chemistry behind one of my favourite foods, popcorn! This project provides an in depth look at the composition of popcorn, the factors that allow it to pop, as well as the many molecules and chemicals that make up the aroma and smell. In addition to this, popcorn brands are compared and health issues that may arise during manufacturing are explored.

Popcorn Composition Popcorn is composed of three main layers. The first, and outer most layer, is known as the pericarp. This is an outside shelling that provides strength and durability to the kernel. It can come in many colours including yellow, white, black, and even red. Underneath the pericarp, exists the endosperm. Water and starch are both trapped within this layer. It also contains smaller parts protein, fat, and minerals. The final layer is the germ (also known as the embryo). This is the makeup of the seed that eventually pops. Finally, is the tip cap, the part joining the kernel, which would have attached to the cob.

What Makes Popcorn Pop! H2O is trapped in the endosperm. As the kernel heats up, H2O begins to change state from liquid to gas. Steam begins to expand, thus building up pressure in the pericarp. The endosperm grows increasingly inflated until the pericarp gives way to the kernel. The popcorn explodes as it flips inside out, steam escapes, and the white fluffy starch is exposed. At this moment, your popcorn has just “popped”!

Popcorn Aroma Popcorn odour comes from molecules released into the air as popcorn is heated. Recent spectroscopic studies have determined over fifty chemical compounds that contribute to the aroma and flavour of popcorn. Some names may sound familiar after studying organic chemistry, while others are completely new. Several examples include…

Aroma Chemical Compounds 2-methyl propanol Hexanoic acid Pentanol Furfuryl alcohol

Flavour In some popcorn, such as the microwavable kind, flavourings are added which contribute to the aroma. Ex.) Butter-flavoured popcorn can include the chemical compounds 2,3-butanedione or 2,3-pentanedione

Health Hazards Popcorn is generally thought to be a healthy option when choosing a snack. It is a good source of dietary fiber and low in calories, when eaten plain. Unfortunately, if your go to snack is microwavable popcorn, you may be missing out on the many benefits of eating popcorn and instead, putting yourself in harms way. Recent studies conducted by Chemical Research in Toxicology have identified the chemical compound 2,3- butanedione, better known as Diacetyl (DA), in artificial butter flavouring. A high quantity of DA in the body may result in a dangerous build up of plaque in the brain. This leaves the body susceptible to Alzheimer’s disease, toxic effects on nerve cells, and penetration of the blood-brain barrier by unwanted substances.

Health Hazards 2.0 The chemical compounds added for flavour pose a serious respiratory threat for workers in factories that manufacture these compounds. The condition is known as “popcorn lung”, with the medical name bronchiolitis obliterans. As the name suggests, the condition obstructs the airway and makes breathing difficult for the victim. Popcorn lung can be crippling, as the effects are irreversible in the small airways. If serious enough, lung transplant may need to be considered as a treatment option.

Popcorn Brands & Popability The list of different microwavable popcorn manufacturers is nearly endless. Many different companies have created their own version of the snack, so the question to be asked is “how do they differ?”. The quality of a bag of popcorn is largely based on the “popability” of the kernels inside. This refers to the ratio of popped kernels vs. unpopped kernels. The secret to good popability lies in the outer shell of the kernel and it’s chemical composition. Kernels that are more likely to pop tend to have a strong outer hull with a highly ordered crystalline structure. Another factor playing into the likeliness of popping is the water composition in the endosperm. Scientists have determined that the ideal moisture content is approximately 14% of the kernel’s weight.

Popcorn Brands & Popability 2.0 Researcher and food chemist, Bruce Hamaker, investigated the matter of unpopped popcorn kernels. Through his studies, he discovered some of the best popcorn brands had a failure rate of only 4%, while the worst brands failed to pop 47% of the kernels. A popular brand, Orville Redenbacher claims to have a popcorn popability in which 98% of their kernels pop.

Total Time Spent on Research: Research Log March 3rd  1 hour March 15th  1 hour April 7th  1 hour May 4th  2 hours May 5th  1 hour May 18th  0.5 hours May 25th  1 hour Total Time Spent on Research: 7.5 hours

Sources Reid, D. J. (2015). Popcorn. In World Book Encyclopedia. (Vol. P, pp.659). Chicago, IL: a Scott Fetzer Company Wilkinson, B. (n.d.). The Chemistry of Popcorn. Retrieved April 07, 2017, from http://www.chemistryislife.com/t-3 Brunning, A. (2017, January 19). What Makes Popcorn Pop? – The Chemistry of Popcorn. Retrieved April 07, 2017, from http://www.compoundchem.com/2017/01/19/popcorn/ Walradt, J.P. (1969). Flavor Chemistry of Popcorn. Retrieved April 07, 2017, from http://www.worldofchemicals.com/228/chemistry-articles/chemistry-of-popcorn-aroma-popping.html Anonymous (n.d.). Chemistry of popcorn aroma & popping! - World Of Chemicals. Retrieved April 07, 2017, from http://www.worldofchemicals.com/288/chemistry-articles/chemistry-of-popcorn-aroma-popping.html American Chemical Society. (2005, April 15). The Chemistry Of Popcorn: It's All About 'Pop-Ability' Retrieved May 25, 2017, from https://www.sciencedaily.com/releases/2005/04/050415112829.htm