The Chemistry of Peppermint Candy

Introduction

Main Chemicals, Compounds, Components

Peppermint:

Peppermint is a hybrid cross between watermint and spearmint, two types of mentha plant. The components of peppermint oil are menthol C10H20O, menthone C10H18O, methyl acetate CH₃COOCH₃, isomenthone C10H18O, limonene C10H16, b-pinene C10H16, menthofuran C10H14O, a-pinene C10H16, germacrene-d C15H24, trans-sabinene hydrate C10H18O, and pulegone C10H16O. The two main components of peppermint oil are menthol and menthone. Menthol is a waxy, clear, crystalline substance. It is a solid but can slightly melt above room temperature. Menthol is obtained from mint oils but can be made synthetically. It can be extracted from mint leaves with the use of distillation. Menthone is a naturally occurring compound and a monoterpene and a ketone. Peppermint oil is naturally occurring and can be extracted from a peppermint leaves. It is extracted by steam distillation from the fresh plant with a yield for 1%.

Sugar (Sucrose):

Sucrose is a disaccharide (double sugar). It is made of one molecule of glucose and one of fructose. It has the formula of C12H22O11. Sugars are white, odorless, crystals that have a sweet taste. It is a single isomer (2 or more compounds with the same formula but a different arrangement of atoms). The molecule is a disaccharide and has a combination of the monosaccharides with glucose and fructose. Sugars are carbohydrates that are made of hydrogen, carbon, and oxygen. Sucrose is naturally occurring, it is found in sugar canes and sugar beets. It is soluble in water and although naturally occurring, it can synthesized in a lab. The cane or beet is smashed and juiced, then the juice is eventually made into sugar crystals through heat and purification.

Chemistry's Role

Mint candies/Candy Canes are made mostly of sugar. The sugar is melted and becomes a workable syrup which can be manipulated. Sucrose actually does not melt at high temperatures, it actually decomposes at around 186°C and forms a caramelly syrup. The decomposition formula for sucrose is: C12H22O11 + heat → 3CO2 + 5H2O + 6H2. Corn syrup is added to stop sugar from crystallizing. Crystallization would cause the candy to have a grainy appearance and brittle structure which is to be avoided. It also stops the candy from being transparent. Water is added to dilute the sugar and is boiled out afterwards. Peppermint oil is used to flavor the candy and give it its minty taste. The reason mint feels cool on your tongue is 2-isopropyl-5-methylcyclohexanol (proper name of menthol) binds to a receptor site on sensory neurons, the TRPM8 receptor. Doing this opens a pore, then calcium ions move into the cell. This process creates an action potential which then sends a message to the brain. This same receptor reacts to cool temperatures. It sends the same message to the brain and the brain cannot distinguish between them, so menthol feels cool.

Background Research

Peppermint candies are manufactured in a factory. The process of making peppermint candies first starts with blending the ingredients together in a kettle with mixers. Water, sugar, corn syrup, and any other processing ingredients are blended together and heated to over 141.5°C until it becomes a golden brown liquid. The liquid is then poured on cooling tables then is stretched by working machines until it is white. While it is being stretched out flavoring is added. A worker takes a large amount of the candy and forms it into a loaf. Part of this is cut into strips and dyed red. They are then pressed into the white candy. The loaf then goes through an extruder and is cut into either strands that are then bent to make a candy cane, or circles to make small candies.

Resources

http://idop2science8.pbworks.com/w/page/40024914/Chemistry%20of%20mint

Information on mint

Why menthol feels cold on the tongue

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

Information on methyl acetate

Chemical formula of methyl acetate

http://www.rsc.org/chemistryworld/2013/04/menthol-podcast

Information on mint

Information on menthol

http://goodhealth.freeservers.com/MenthUseThisOne.htm

Uses of menthol

http://www.madehow.com/Volume-7/Candy-Cane.html

How candy canes (or round peppermints) are made

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

Information on sugar

Chemical formula of sucrose

http://www.britannica.com/EBchecked/topic/571880/sugar

More information on sugar

http://www.cornnaturally.com/hfcs-scientific-data/HFCS-Nutritional-Equivalencies/Composition

Chemical formula for corn starch

http://pubchem.ncbi.nlm.nih.gov/compound/6850741

Chemical formula for peppermint oil

About the Author

Mariah Alberti is a junior at Billings Senior High School. She enjoys dancing, writing, science, and watching films. She plans on continuing with chemistry and wants to attend an out of state college after next year. Her main goal is to travel the world someday.