The Chemistry of Popcorn

Introduction

YouTube Video

Popcorn is a popular, healthy treat for many people, usually eaten while one is watching a movie.  There are many things one could add to popcorn like butter or caramel.  Popcorn comes in different kinds; white, small yellow, and large yellow.  It also comes in different shapes like butterfly, most preferred by people, and mushroom shapes.  I choose this topic because I enjoy eating popcorn, but I never really understood how it pops.  All you do is add some heat and all of the sudden that little, hard kernel is a piece of soft, edible popcorn!  There is water in the kernel of the popcorn and as the water heats up it expands into steam.  Eventually the pressure from the steam ruptures the kernel, and it turns the kernel inside out! Now it’s ready to eat!


Composition of ...
  • Popcorn

  • Coconut oil

  • Starch (C6H10O5)

  • Beta-carotene (C4OH56)

  • Salt (NaCl)


Main Chemicals, Compounds, Components

The pericarp is the outer shelling of the kernel and is made of cellulose.  The pericarp can be multiple colors including red, black, yellow, or white.  Underneath the pericarp is the endosperm, which contains the trapped water and the starch.  The germ is the seed that allows the popcorn to pop.  The water in the endosperm turns to steam, which builds up the pressure in the pericarp.  During all of this the starch turns into a gelatinous material.  About 9.2 atm the pericarp ruptures and the gelatinous starch becomes a solid.  The endosperm is usually white or yellow, depending on the type of popcorn.  


Chemistry's Role

Popcorn is naturally grown on a stock, like regular corn.  The starch and water that is needed to pop the kernel is naturally found in the kernel.  Most people add salt (NaCl) to their popcorn to give it some flavoring.  When the kernel is heated up the water in the kernel turns into expanding steam, which builds up the pressure in the kernel.  This steam turns the starch into a gelatinous material.  Eventually, the pressure is too much for the pericarp to handle and the kernel explodes.  When the kernel explodes, it turn the kernel inside out.  A lot of variables can affect how the popcorn pops.  These variables include how much water there is in the kernel and how quickly one should heat up popcorn.  Chemists have figured that an ideal moisture content is between 14%.  If it is below that number, the chances of the kernel popping decrease.   Chemists have also figured out that  if popcorn is heated up too quickly the kernel not pop all the way and will have a hard center.  If the kernel is heated up too slowly, it will not pop at all.  Following the directions on the popcorn will insure that one will have good popcorn.  


Background Research

There are four different types of corn: sweet, dent, flint, and popcorn.  Popcorn is the only one that actually pops.  It usually takes 110 days or more to grow popcorn, so one should plant in early spring.  The kernels needs about 13.5% to 14% water to have the kernel pop.  The pressure will reach to about 135 pounds per square inch before popping and up to about 180 degrees Celsius or 365 degrees Fahrenheit.  Kernels will grow to be 40 to 50 times bigger than their original side. Microwavable popcorn is made by putting salt, soybean oil, flavoring, and corn kernels into tight microwaveable bags.  During the Great Depression popcorn was very popular since it was so cheap, they ate about three times as much popcorn as we do today.  Also, in the 1800s popcorn was a popular breakfast cereal commonly served with milk and a sweetener.  


Resources

http://chemistry.about.com/od/foodcookingchemistry/f/how-popcorn-pops.htm

How popcorn pops

http://www.hort.purdue.edu/newcrop/afcm/popcorn.html

History of popcorn

How it grows and how to grow popcorn

Describes the kinds of environments and how to take care of it properly

How to store it properly

Types of popcorn

Economics

http://www.popcorn.org/ForTeachers/TeachingGuide/WhatMakesPopcornPop/tabid/88/Default.aspx

Native American history that deals with popcorn

Overview of the parts of popcorn: germ, endosperm, and pericarp

Describes how it pops

http://www.carolina.com/teacher-resources/Interactive/the-science-of-popcorn/tr23952.tr

Goes into detail of the different parts of popcorn

What causes it to pop

http://www.joybauer.com/what-the-heck-are-you-eating/whats-in-microwave-popcorn.aspx

Nutritional facts about popcorn

http://www.garrettpopcorn.com/service/nutritional-information/

Ingredients in popcorn

http://en.wikipedia.org/wiki/Popcorn

Describes what causes popcorn to pop

History of popcorn



About the Author

popcorn2.jpgBrittaney Wilkinson is a junior at Billings Senior High.  She has high hopes on becoming a valedictorian and becoming a nurse.  Brittaney is currently on National Honors Society and plays in the Philharmonic Orchestra at Senior High.  She enjoys playing her violin, reading, and hanging out with friends.  Currently, her main classes are honors english, honors algebra 3, and chemistry.  


Comments