How Sweet It Is: Functional Sweeteners

How Sweet It Is: Functional Sweeteners

by Kim Schoenhals

Ingredients added to foods and beverages for the sweetness theyimpart also add functionality. From altering the mouthfeel and viscosity toenhancing flavor and humectancy, sweeteners offer a range of function for everyconceivable food or beverage product.Candy, cake, pie, soda--these are thethings that make mouths water. Sweetness is something people crave and seek out,and manufacturers are more than willing to supply it. Americans consume about 64pounds of sugars per year, according to the U.S. Department of Agriculture's(USDA) Continuing Survey of Food Intake of Individuals. However,according to the Sugar Association, this number is a misrepresentation of"sugar" consumption. Technically, the only sugar that can be labeledas such is sucrose, according to the association, which estimates Americansconsume 29 pounds per year of actual sucrose.

"Historically, sugar (sucrose), the natural carbohydratederived from sugar cane and sugar beets, has been the predominantsweetener," according to the Sugar Association. "But over the past 20years, a slew of new caloric sweeteners have been developed and introduced tothe market, including fructose, glucose, high fructose corn syrup andmaltose."

While probably not many consumers spend much time contemplatingtheir yearly intake of sucrose versus other caloric sweeteners, there are manytechnical differences and functional considerations regarding the various typesof sweeteners available for food and beverage use.

Sweeteners can be broken down into several categories: nutritiveand nonnutritive, low- and high-intensity, and natural and artificial. Nutritivesweeteners, such as sucrose, are metabolized by the body and provide calories,while nonnutritive sweeteners, such as sucralose, are not metabolized and arenon-caloric. In many cases, nutritive sweeteners are also low-intensity andnatural, while nonnutritive sweeteners tend to be high-intensity and artificial.As with most rules, exceptions do exist. Stevia, for example, is ahigh-intensity, nonnutritive sweetener that is considered natural.

So, how do manufacturers go about selecting a sweetener--orsweeteners--for food or beverage applications? Many times, it is thefunctionality, both in terms of health and physical attributes, which drawsmanufacturers to particular sweeteners over others, in addition to applicationneeds.

A Matter of Function

Sucrose is generally used as the proverbial yard stick by whichall other sweeteners are measured. In terms of sweetness, most sweeteners aredescribed as a percentage of (or a number of times) the sweetness of sugar.Nutritive sweeteners tend to be as sweet as or less sweet than sucrose, whilenonnutritive sweeteners are often several hundred times sweeter.

"Nutritive sweeteners are carbohydrates that impartsweetness to some degree, usually less than that of sucrose," said KennethMeincke, vice president of sales and marketing at Copenhagen, Denmark-basedDanisco, which supplies xylitol, a naturally occurring nutritive sweetener.

Aside from the obvious sweetness factor, sweeteners have severalfunctions in food and beverage products. They can reduce calories, serve toenhance flavor by masking off-notes, and add body, bulk, texture and viscosity.They can also impart health and nutrition benefits.

"Sweeteners, whether they are caloric or non-caloric,low-intensity or high-intensity, offer a lot of functional properties to foodproducts, not just sweetness," said Bryan Tungland, vice president ofscientific and regulatory affairs at Monmouth Junction, N.J.-based SensusAmerica, maker of Frutafit brand inulin and Frutalose brandfructooligosaccharides (FOS). He noted sweeteners affect the microbiologicalsafety of food products, provide browning characteristics, viscosity, body andmouthfeel, and affect the dielectric constant (a measure of how molecules movewhen they are energized, which affects a food's ability to heat).

Meincke added, "Sweetness is not necessarily the primaryreason for using nutritive sweeteners, as they will most often be included informulations for their functional benefits, while at the same time reducing theimpact of calories or carbohydrate load, such as in a low-glycemic diet.Nutritive sweeteners have bulk and are used in the same proportions as sugar orsimilar carbohydrates providing body, structure and texture to food products.They may also be used in conjunction with nonnutritive sweeteners to enhance thesweet taste."

Xylitol, for example, has the same sweetness and bulk of sugarwith 40-percent fewer calories. It is known for its rapid rate of dissolution,which gives it a "quick hit" of sweetness, and it also has a perceivedcooling effect, which enhances mint and fruit flavors, according to Meincke. Inaddition, xylitol is hygroscopic and adds humectancy.

One of the benefits of using xylitol in a food or beverageapplication, according to Meincke, is that it is a low-glycemic sweetenermetabolized independently of insulin, meaning it does not cause a sharp increasein blood sugar levels or the associated serum insulin response. This makesxylitol well-suited for sugar-free and diabetic applications.

A big draw in the search for an alternative to sucrose is makinglow- and non-caloric foods or beverages. There is a growing market forsugar-free (which only means sucrose-free, according to the Sugar Association)and low-calorie products, especially in the United States, where more than 60percent of the adult population is overweight and 25 percent is obese. Inreplacing sugar in a food or beverage, depending on the sweetener, there may beseveral manufacturing issues to address.

"There are a number of bulk properties of sugar that needto be adjusted for when replacing sugars with any low-calorie sweetener,"said Carolyn M. Merkel, Ph.D., executive director of ingredient technology atNew Brunswick, N.J.-based McNeil Nutritionals, maker of Splenda brandsucralose. "These properties include humectancy, browning and bulk, amongothers. If the product contains significant amounts of water, frequently thebulk properties can be made up with the addition of more water. However, if theproduct is lower in moisture, then the formulation needs to be adjusted toaccount for the difference in bulk."

According to Merkel, no processing adjustments are necessarywhen replacing sugars with sucralose--a nonnutritive, high-intensity sweetenerderived from sucrose--because it is completely heat-stable. "Sucralose hasthe clean, sweet taste of sugar without the calories of sugar," Merkelsaid. "It offers a manufacturer the option to provide sweetened foods andbeverages that taste good but don't have the added calories or carbohydratesassociated with sugar."

Another nonnutritive, high-intensity sweetener on the market forlow-calorie applications is acesulfame-K (Ace-K). According to literature fromSomerset, N.J.-based Nutrinova Inc., maker of Sunett brand Ace-K, thecompany's partial sugar replacement concept involves replacing part of thenutritive sweetener content of a product with Sunett or a combination ofsweeteners. Up to 80-percent sugar replacement is possible, according to thecompany, while still maintaining mouthfeel, taste and sensory properties.

"Partial sugar replacement means lower overall sweeteningcosts, reduced storage requirements and lower logistical costs," accordingto Nutrinova. "Syrups in which sugar is partially replaced can be producedin higher concentrations and brought to market in smaller container sizes."

Research conducted by Nutrinova indicated carbonated lemon-limebeverages sweetened with a ratio of 30-to-70 Sunett-to-aspartame blendmaintained quality and flavor in a fashion similar to the sucrose controlbeverage--and more effectively than six other sweetening systems.

Some ingredients that impart a touch of sweetness to food andbeverage products may not actually be classified as sweeteners. Trehalose,inulin and oligosaccharides are a few such ingredients. These are oftencategorized as functional carbohydrates, functional fibers, sweet bulking agentsor, in the case of inulin and FOS, prebiotics. These ingredients are often usedin combination with sweeteners to enhance mouthfeel and body, as well as to adda touch of functionality.

Two sweet bulking agents available on the market today areBeflora and Beflora Plus. These ingredients, imported by Manasquan, N.J.-basedRoxlor International and distributed in the United States by Wayne, N.J.-basedTriarco Industries Inc., are a combination of oligofructose, mung bean extractand a very small amount of Ace-K.

The functionality Beflora and Beflora Plus add to food andbeverage applications is enhanced taste, low-calorie sweetness and improvedgastrointestinal health as a function of the prebiotic fiber. Beflora andBeflora Plus also affect mouthfeel, hold moisture and add texture to finishedproducts, according to Mark Anderson, Ph.D., director of R&D at Triarco.

While Beflora and Beflora Plus may not be suitable for acidicapplications (pH 3 and lower), they are good candidates for mixing with othersweeteners, according to Chuck Messenger, president of Roxlor International."We generally say artificial, or nonnutritive, sweeteners are goodcandidates for blending with Beflora Plus," Messenger said. "And it'snormally a 75-25 blend--75 parts artificial sweetener and 25 parts Beflora Plus.Beflora has a great capacity to round out the mouthfeel and flavor and eliminatethe metallic taste you can get when using a nonnutritive sweetener. It alsoworks particularly well in soy-based products to mask the beany taste ofsoy."

Tungland noted inulin is also effective for masking off-notes,and adds the benefit of a prebiotic fiber to the product it enhances. "Inulinadds a very selective prebiotic dietary fiber to products in addition to makingthose products be perceived as their whole-fat, full-sugar counterparts,"he said. "You don't lose taste quality, and in many cases, you increasetaste quality by masking some of the off-notes like soybean aftertaste. Inulindoes an excellent job of masking or enhancing the attributes to suppress thesoybean aftertaste. Suppressing the high-intensity sweetener aftertaste isreally important to make sugar-free products."

Because inulin is not sweet enough to be used as a solesweetener, it is a good candidate for combining with nonnutritive sweeteners."The high-intensity sweeteners are used typically with non-caloricsweeteners like high-fiber bulking agents," Tungland said. "Inulindoesn't add a lot of sweetness, but it has mouthfeel effects and some browningeffects. But because bulking agents are not really sweet by themselves,manufacturers can pick up the sweetness with a high-intensity sweetener."

In addition to adding mouthfeel and browning effects, sweetbulking agents can also serve to mask off-notes. Inulin and FOS, for example,are often used in combination with high-intensity sweeteners to mask thecharacteristic metallic off-notes. "The biggest problem with high-intensitysweeteners is they have a bitter or metallic aftertaste," Tungland said."You typically try to mask some of those effects with the bulking agentsyou choose. Inulin, by example, and FOS do an excellent job of reducing thehigh-intensity aftertaste. When you develop a system with inulin and ahigh-intensity sweetener, it performs more like a true sugar, but extremelylow-calorie."

Inulin and FOS also improve viscosity and mouthfeel, are highlysoluble and a good fiber source, can be used in sugar-free applications, andaffect appetite control, blood lipids, lower cholesterol and triglycerides, andpositively affect blood glucose.

Jim Kappas, director of sales and marketing at Cargill Health& Food Technologies in Minneapolis, noted inulin adds bulk to a productwhile reducing the total calorie content, and it may help boost calciumabsorption.

One consideration that has to be kept in mind when using inulinis the prebiotic does not work well with acidic products. "For beverageapplications, the main factor to be aware of is that at a very low pH, inulinconverts to fructose," Kappas said. "It hydrolyzes to fructose anddoes not maintain its low-calorie and fiber properties, and tends to be usedmore in systems about 3.8 pH."

Like inulin, trehalose--another sweet carbohydrate--positivelyaffects blood glucose levels. "Trehalose is a newly available carbohydratethat helps maintain low insulin response as compared with glucose," Kappassaid. "It's about half as sweet as sucrose, so manufacturers don't reallyuse it for its sweetness alone. The two key properties in trehalose that make itinteresting are 1) metabolically, it has a very low insulin response comparedwith glucose, and 2) physically, trehalose works as a functional sweetener tostabilize proteins."

According to Kappas, trehalose adds sensory properties to foodand beverage products and has a very "clean sweetness," which ismilder than sucrose or fructose. It's also less soluble than sucrose by abouttwo-thirds.

The GRAS Issue

One of the biggest issues with food additives is GRAS (generallyrecognized as safe) status, as determined by the Food and Drug Administration(FDA). While not all sweeteners are GRAS for use in food and beverageapplications, some are approved as general purpose sweeteners.

Sucralose, for example, is an approved general purposesweetener, although it is not GRAS, according to Merkel. "The lack of GRASapproval does not limit the use of sucralose in products, unless a manufacturerhas a policy of not using a material unless it is GRAS," Merkel said."Since it is extremely difficult to make products that are entirely GRAS,reduced in sugar or sugar-free and taste good, I have not seen the lackof GRAS status limit the use of sucralose."

Xylitol is another example of a sweetener that does not haveGRAS status, but is approved for use as a sweetener. Xylitol has been fullyassessed by FDA and approved for use in food since 1963, according to Meincke."GRAS is only one form of regulatory approval, and there are many levels ofGRAS approvals that can be applied," he said. "But GRAS does notnecessarily mean a food or ingredient has been reviewed by FDA."

One high-intensity sweetener not approved for use in food orbeverage products in the United States is stevia, an all-natural,high-intensity, nonnutritive sweetener. The plant-derived sweetener has beenthrough the ringer in the United States, with FDA refusing to approve its GRASstatus for food or beverage applications. In fact, FDA labeled stevia as an"unsafe food additive" back in the 1980s and has not reversed thisdecision, although with the passage of the Dietary Supplement Health andEducation Act (DSHEA), stevia can be marketed as a dietary supplement.

Several energy beverages and bars are marketed and labeled asdietary supplements, and as such are allowed to contain stevia, or derivativesof stevia. Stevia contains eight glycosides (sugars), one of which isRebaudioside-A. Honolulu's Sweet Aloha Farms is currently compiling research andscientific data in its application to FDA for GRAS status--specifically for thecompany's Rebaudioside-A product, SoooLite!, which is a nonnutritive,high-intensity (350 times sweeter than sugar) sweetener. While the glycoside isnot approved GRAS at this point, like stevia it can be used as a dietarysupplement under DSHEA.

"In the U.S. natural products market, when SoooLite! isused as a supplement, manufacturers can make the claim of 'all-natural' and, ontop of that, there is some functionality," said Marty Parisien, vicepresident of Sweet Aloha Farms. "Rebaudioside-A is proven to reduce bloodsugar levels and the data does substantiate claims that it reduces bloodpressure levels."

In addition to its functional benefits, Rebaudioside-A isparticularly attractive for natural products applications because it isall-natural, according to Parisien. And, he noted, Rebaudioside-A has a widerange of applications. Because it is heat-stable (it has been tested up to 150degrees Celcius), it is a good match for baking applications, and because of itslingering sweetness profile, it is good for gum, as well. Rebaudioside-A is alsopH-stable, and is well-suited for carbonated beverages, alcohol-typeapplications and as a flavor enhancer. "Aspartame breaks down with cinnamonor cherry or vanilla, and loses its sweetness very rapidly," Parisien said."Rebaudioside-A doesn't. So, many flavor houses are looking at using italong with cinnamon because some of the chemical sweeteners can't be used inthat arena."

Especially in the case of non-GRAS ingredients, manufacturersshould be cognizant of labeling details, according to Parisien, to remain incompliance with FDA and improve the industry's image. "The supplementindustry in the United States as a whole needs to do a better job ofself-regulation," Parisien said. "Right now, there are a lot of verybad claims being made. Instead of giving the industry a bad name through badpress and FDA recalls, the industry should regulate itself. And that's whatwe're doing. We're ensuring that we have a product and a company and a brandthat are associated with the highest integrity, research and quality."