Chew on This—The Chemistry of Gum
Article originally from American Chemistry magazine
Originally chewed in ancient times to clean teeth and freshen breath, gum has come a long way in terms of its chemistry over the years. New research, for example, shows today’s sugar-free chewing gum can reduce symptoms related to heartburn, including acid reflux.
When you reach for a stick of gum, you might want to chew over the following facts.
What it’s made of
Many ingredients go into a piece of gum, beginning with the base. The gum base puts the "chew" into the product by binding all the ingredients together for a smooth, soft texture. While some bases are made with synthetic materials, such as a man-made latex, others are made with pure powdered cane sugar, beet sugar, and corn syrup.
Several types of sweeteners are used in sugar-free gum, including acesulfame K, aspartame, maltitol, sucralose, and xylitol.
Glycerin and other vegetable oil products keep gum soft and flexible by retaining the proper amount of moisture. Ingredients like mannitol and sorbitol ensure the proper density.
The most popular flavors for chewing gum are variations of mint. The flavoring for these gums is extracted from fresh mint plants grown on farms. After the plants are harvested, they go through a distillation process that extracts the oils used for flavoring different brands.
Some brands are also flavored by a variety of fruit and spice essences. Colorings are used to distinguish between different flavors.
How it’s made
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| The candy shell coating found on bubble gum is made from a mixture of filtered water, sweeteners, and coloring. |
From the mixture, a large portion of gum is sent through a series of rollers that form it into a thin, wide ribbon. Each pair of rollers is set closer together than the previous pair, gradually reducing the thickness of the gum as it passes through them. A light coating of finely powdered sugar or sugar substitute is added during this process to prevent the gum from sticking and to enhance its flavor.
At the end of the rolling process, the continuous ribbon of gum is then cut into a pattern for sticks, tablets, strips, or rectangular centers, depending on the type of gum being made. The gum is then moved to a temperature-controlled environment to cool. This ensures the finished product will have the right consistency and stay fresh on store shelves.
After a heat treatment (referred to as "tempering"), the gum centers are broken into individual pieces. The pieces are then fed into a spray drier that forms the crunchy coating around the center. It tumbles the pieces while a prepared syrup mixture, made of filtered water, sweeteners, and coloring, is sprayed onto the gum. This combination of tumbling and spraying forms a candy shell around the soft centers.
After cooling and tempering, operators break the sheets of sticks into sections and feed them into the wrapping machine.
Pellet-style gum can be packaged by two different methods. The first is to place the pellets into the formed plastic compartments of a blister pack. The package is heat-sealed with a foil backing and inserted into a sleeve. The second method is to line up 10 pellets in a row, wrap them in traditional paper and foil packaging, and seal both ends to ensure freshness.
Chew on and on
Years after its invention, gum continues to be popular today. It is estimated that 50 percent of Americans chew gum, averaging about 170 servings per person per year. Its consumption varies around the rest of the world—for example, in Singapore, chewing gum is illegal, except when sold as a medical product for therapeutic purposes.
With files from Wrigley and Tootsie Roll Industries.