Sweetener Options Offer Benefits to Formulators

by HeatherGranato

"A spoonful of sugar helps the medicine go down." The same goes for nutraceutical and functional food products. Sweeteners allow formulators to cover off notes, emphasize positive taste attributes and even meet necessary specs. As the range of available sweeteners expands, companies are exploring the abilities of all types of sweetening agents to make their products go down easier.

A review of sweeteners published by the American Dietetic Association (ADA) in the Journal of the American Dietetic Association (98:580-87, 1998) breaks sweeteners down into two primary categories: nutritive and nonnutritive. Nutritive sweeteners provide a sweet taste and a source of energy (calories); nonnutritive sweeteners are sweet without providing energy. The sweetening power of these ingredients varies with the properties of the food, such as physical state, temperature and the presence of other flavors. Some sweeteners are considered generally recognized as safe (GRAS), while others are classified as food additives.

Nutritive Sweeteners

Nutritive sweeteners include sugar sweeteners such as refined sugar or honey, as well as energy-reduced polyols or sugar alcohols. Sucrose and fructose are the primary nutritive sweeteners in the food supply. Sucrose is a disaccharide composed of glucose and fructose, each of which is a monosaccharide. ADA noted, "These sweeteners add functional properties to foods through their effects on sensory (e.g., flavor of molasses), physical (e.g., crystallization, viscosity), microbial (e.g., preservation, fermentation) and chemical (e.g., carmelization, antioxidation) characteristics."

According to the Sugar Association, the only sweetener the U.S. government permits to be called "sugar" on product labels is sucrose. It noted that while purified sugar annual consumption (on a per pounds/per person basis) has decreased from 102 pounds in 1970 to 69 pounds in 1999, consumption of other corn sweeteners (which have a high degree of monosaccharides) has increased 463 percent from 19 pounds in 1970 to 88 pounds in 1999.

Natural source monosaccharides (such as fructose or glucose) have proven attractive to many natural and functional food companies because of their low glycemic index compared to glucose, as well as their intense sweetness. Corn syrups or solids, for example, have a high quantity of fructose. ADM Corn Processing in Decatur, Ill., offers a line of CornSweet® high-fructose corn syrups, as well as corn syrup solids. According to Allan Buck, ADM's director of Technical Services Food Ingredients, fructose offers functional benefits including a low glycemic index, humectant properties, fermentation qualities (which can impact product flavor) and binding abilities.

Comparatively, rice syrups contain primarily glucose or maltose. "Demand for rice syrups has grown steadily," said Joe Hall, technical sales manager at California Natural Products in Lathrop, Calif. "The primary driving force for acceptance is two-fold. First, the syrups work with soy-based products to both sweeten and reduce the beany notes so typical of soy. Second, the syrups have excellent functionality in extruded or baked bar products, acting as sweetener, binder and humectant."

Another nutritive category is the polyols, which can be characterized as sugar replacers and can often be used on a one-to-one basis with sugars. Polyols offer a range of functional benefits, according to Donna Brooks, product manager with New Century, Kan.-based Danisco Cultor. "Replacing sugars with ingredients that not only replace the sweetness and bulk of sugar, but also improve the nutritional profile of the food by virtue of being sugar free, low calorie, low glycemic and providing other health benefits, such as adding fiber, offer manufacturers a range of possibilities," she said.

One of the best-known polyols is xylitol, which has received public recognition for its ability to prevent dental caries. Xylitol, a naturally occurring 5-carbon polyol, is the sweetest of all polyols and has minimal effects on glucose and insulin levels. Some companies, such as Danisco Cultor, use renewable natural resources to produce xylitol.

Polyols such as xylitol and sorbitol are found in plant products, but they are generally produced synthetically for commercial use. One branded polyol sweetener, Litesse® from Danisco, is a polydextrose fiber that is produced from a combination of glucose, sorbitol and citric acid.

The natural compound inulin may also offer benefits as a sweetener and fiber agent. Inulin is usually extracted from chicory root and is a natural soluble fiber. Among the companies supplying inulin are Cargill Health & Technologies in Minneapolis (Oliggo*Fiber™) and Imperial Sensus in Sugar Land, Texas (Frutafit®). According to Imperial Sensus, inulin offers four advantages to formulators: synergy in sweetness, masking off- and after-tastes, improved mouthfeel and additional health benefits (attributed to its serving as a soluble dietary fiber).

Nonnutritive Sweeteners

Nonnutritive sweeteners such as acesulfame-K (Ace-K) and sucralose offer no energy and sweeten with little volume, giving rise to their other common name, high-intensity sweeteners (HIS). The United States leads the world in consumption of HIS, consuming approximately 50 percent of the world demand, according to ADA. That consumption is only increasing. A study by the U.K. market research firm Freedonia estimates that the market for nonnutritive sweeteners in the United States will increase to $685 million by 2004.

ADA noted that the current trend in the food industry is to blend HIS with each other or other nutritive sweeteners. "Blending can cause sweetness synergy, which can decrease the amount of sweetener needed and can improve the overall sweet taste," ADA wrote. Four nonnutritive sweeteners have been approved for food additive status in the United States: saccharin, aspartame, Ace-K and sucralose. Suppliers of Ace-K and sucralose are targeting the nutraceutical market, promoting the functional benefits of HIS in food and beverage products.

Ace-K was discovered in 1967 by Hoechst AG and is approximately 200 times sweeter than sucrose. It is not metabolized by the body and is excreted unchanged. The primary supplier isNutrinova, a Hoechst subsidiary, that sells the Sunett™ brand of Ace-K. The company noted that Ace-K is stable within a wide range of temperatures (in production and storage) and pH levels.

Nutrinova conducted a study at the University of Tennessee reviewing how a blend of Sunett and aspartame to sweeten Diet 7 UP® fared versus the current aspartame-only version. According to the company, two-thirds of respondents preferred the product with the HIS blend. "These findings represent positive news for us," the company said. "Blending Sunett with other sweeteners or sugars ... confers significant sensory benefits."

Blending has benefits both for reducing calories and decreasing the bitterness associated with Ace-K. One study of 65 subjects found that bitter responses were recorded for Ace-K, which may have a common mechanism for bitter taste reception and transduction (Chem Senses, 27, 1:31-8, 2002).

Flavor chemists are also providing solutions to give sweeter flavor to products containing possibly bitter HIS. The Treattarome™ line of FTNF (from the named food) distillates from Florida Treatt now includes two flavors from sugar and honey. According to the company, the line concentrates the volatile flavor compounds without the sugar content, which can blend synergistically with nonnutritive sweeteners to give the perception that natural sugar was added to the product.

Sucralose is known commercially as Splenda®, and is patented and supplied by McNeil Nutritionals. The compound was discovered in 1976 and today is approved for consumption in more than 50 countries. It is produced by selectively replacing three hydrogen-oxygen groups on a sugar molecule with three chlorine atoms. According to McNeil, the structure is tightly bound, preventing it from being broken down and metabolized by the body. It is also 600 times sweeter than sucrose.

Internet sites on Ace-K and sucralose have raised possible health concerns linking intake with an increased risk of cancer or diabetes. The Joint Expert Committee on Food Additives (JECFA), the scientific advisory body to the World Health Organization and the Food and Agriculture Organization of the United Nations, reviewed the available research on Ace-K and concluded that it is safe. However, some studies have raised concern over its safety, leading one researcher to note in 1997, "In view of the present significant in vivo mammalian genotoxicity data, acesulfame-K should be used with caution." (Food Chem Toxicol, 35, 12:1177-9.)

The primary concerns raised on the Internet regarding sucralose pertain to the changed chemical structure and unknown long-term effects of ingestion. However, studies examining tolerance and toxicity of sucralose in humans and animals have been fairly positive. Two tolerance studies in human adults found no adverse experiences or clinically detectable effects attributable to sucralose (Food Chem Toxicol 38 Suppl 2:S123-9, 2000). The researchers concluded, "Based on these studies and the extensive animal safety database, there is no indication that adverse effects on human health would occur from frequent or long-term exposure to sucralose at the maximum anticipated levels of intake."

Natural compounds may also have application as nonnutritive sweeteners. Stevia, extracted from the herb Stevia rebaudiana Bertoni, is known in the natural products industry for its sweet characteristics; however, it is not GRAS by FDA for inclusion in food products, though it can be sold as a dietary supplement ingredient. "Stevia has a big future in this industry," said Jolene Oliver, owner of Stevia Canada in Ontario. "I predict it will be GRAS approved within a year. There is no reason not to approve it."

While FDA has said sufficient studies have not been conducted on stevia's safety, industry members have compiled data on the product's safety and efficacy. In particular, it may help normalize blood sugar levels. While the mechanism of how it reduces glucose levels remains unknown, in vivo studies have shown it may increase insulin secretion through stimulation of the beta cells in the pancreas (Metabolism, 49,2:208-14, 2000).