A STICKY Situation

Prepared Foods, March, 2001 by Laura A. Brandt

Product developers create chewing gums with longer-lasting flavor, sugar-free sweeteners and health benefits.

Gum chewing dates back to ancient civilizations. In 50 A.D., for example, Greeks chewed mastic tree resin. During the 2nd century, Central American Mayans chewed chicle, a natural gum. American Indians chewed spruce gum made from spruce tree resin that was eventually replaced by paraffin wax gum.

Today's chewing gums--made mostly of synthetic materials--have evolved into colorful novelties of all shapes and sizes as well as more serious functional products that claim to help adults cope with modern problems. This requires product developers to blend technical know-how with psychology, art and creativity.

"As developers of novelty gums and candies, we are asked to find the answer to an impossible question," says Chris Corrivean, vice president, R&D, Amurol Confections Co., Yorkville, Ill.

Although traditional mint-flavored gums and bubble gums remain popular, today's chewing gums are following several key trends such as intense flavors, sourness, sugarless gums, and functional gums.

Chewing Gum Basics

Scientifically speaking, chewing gum is a semi-crystalline, viscoelastic compound. It is a water-in-oil emulsion comprised of five basic ingredients--gum base, sweeteners, corn syrup, softeners, and flavors. The gum base and some of the flavorings are water-insoluble. The other ingredients are water-soluble and are extracted from the gum during chewing.

Chewing gum base is a complex mixture of ingredients: elastomers, resin plasticizers, minerals, waxes, lipids, and emulsifiers. Elastomers provide elasticity and texture. They include natural rubber, natural gums, and styrene-butadiene rubber and polyvinylacetate. Plasticizers act as softening agents and along with minerals, regulate cohesiveness.

Melting of wax and lipid crystals creates the cooling and softening sensation while chewing. Emulsifiers and the hydration of water-loving polymers enhance the mouthfeel of gum flavors.

The basic composition of standard chewing gums is approximately 20% gum base, 60% sugar, 18-20% glucose syrup, 0.5-1% flavor, and 1% other additives (e.g., polyols and glycerin). Bubble gums normally use slightly less bubble gum base and more glucose syrup. Sugarless gums typically have about 25-30% gum base, 50-60% solids such as polyols, 5-6% glycerin and 1.0-1.5% flavor, plus high-intensity sweeteners.

Gum base may be purchased from a supplier, however, most large chewing gum manufacturers produce their own bases, says Steve Synosky, assistant vice president, R&D and 30-year veteran of L.A. Dreyfus Co., a gum base maker in Edison, N.J.

In order to work with a gum base and mix other ingredients into it, the material must first be softened. "At room temperature, gum base is a like a rubbery plastic. You have to soften it in a gum mixer while being careful not to heat it beyond about 221[degrees]F," cautions Synosky.

Once the gum base is pliable, formulators mix the other ingredients into it. Flavors are generally added last to preserve their character. After mixing, the gum cools slightly before extrusion into various shapes. Then the gum is conditioned and aged under controlled temperature and humidity.

While there are many gum bases, the basic types include chewing gum, bubble gum, sugarless gums, non-stick gums, and acid-resistant gums.

Sugarless Gum

Rather than using sugar and glucose syrup, sugarless gum products contain polyols such as powdered sorbitol, mannitol, or xylitol along with a sorbitol solution or hydrogenated glucose syrup. Although these carbohydrates are not truly "sugar-free," they are non-cariogenic.

Sugarless and sugar-containing gums often include high-intensity sweeteners (HIS) such as aspartame, acesulfame potassium (ace-K), saccharin, and sucralose.

Removing sugars from the gum makes flavor impact challenging because sugars and flavors synergize to provide flavor intensity. HIS combined with polyols provide an acceptable sweetness profile. By encapsulating HIS, formulators extend the length of perceived sweetness.

Ford Gum & Machine Co., Akron, N.Y., produces Ford Xtreme sugarless gum and bubble gum with xylitol and sorbitol. The company also markets Xtreme Vitamin C Bubble Gum.

Ford Gum chose xylitol for its unique health benefits, which include preventing dental caries and reducing plaque growth. Clinical studies have shown that xylitol is effective in preventing middle ear infections in children.

"Xylitol retards the growth of Streptococcus mutans, which causes the release of acids upon the breakdown of carbohydrates in the mouth," says Warren Clark, vice president of R&D and QA, Ford Gum. These acids can lead to tooth decay.

Many dental gums include xylitol for these reasons. Also, xylitol's high negative heat of solution provides a strong cooling effect that goes especially well with cool refreshing flavors.

With the FDA approval of sucralose in 1998, chewing gum manufacturers are rolling out products sweetened with sucralose, which is about 500 times sweeter than sugar in these applications, according to the supplier. In chewing gum, sucralose provides a quick initial onset of sweetness and extended sweetness.