Food Product Design: February 2001 - Sweetners for Health Foods

A food product's sweetness is usually one of its most important characteristics. It often distinguishes the product from its competition, and is often the number one property in terms of consumer acceptability along with overall flavor.

But when it comes to making product claims, not all sweeteners are created equal. Depending on the market, certain sweeteners are favored because of a different type of processing (or degree of processing) or because of their origin. Sometimes the selections make technical sense, sometimes not, but often sweetener use spreads by reputation. Some may argue that sucrose is sucrose, no matter what the source, but perception is key.

This means choosing sweeteners for the health market can be confusing, but it helps to pose several questions. Is the product marketed for weight loss, bodybuilding or general nutrition? Is it natural, kosher or organic? And is the food targeted for disease control or for general good health? Another consideration is whether the sweeteners introduced are nutritive or non-nutritive (Do they provide energy?). After that, product designers can consider sources of the sugars, whether as the saccharide alone, whether it comes from a certain source, such as fruits, vegetables, or grains or whether the sweetener is synthesized from something entirely different.

In spite of the process's complexity - or maybe because of it - when choosing sweeteners for today's health-conscious consumer, most of the bases are covered.

Sweet things
Sucrose has historically been the primary sweetener source in processed products, followed by "other sugars," including glucose, fructose, lactose and maltose, and fruit pastes that derive sweetness from these molecules. Sweetening with sugars is accomplished to varying extents by including fruits, cereals, milk and flour (due to naturally occurring sugars), but more sweetness comes from fruit concentrates, honey, invert sugar, molasses and plant-derived syrups (corn syrup, rice syrup, maple syrup, etc.). All of these sugars are nutritionally the same - they are hydrolyzed to monosaccharides in the digestive system, providing energy.
Basically, nutritive sweeteners provide calories. In the past, we have always thought of carbohydrates as molecules that provide a standard 4.0 kcal per gram. This is true of sucrose, maltose, fructose, lactose, glucose, and related sugars. It also applies to most of the products derived from sugar processing - molasses, corn syrups, corn syrup solids, high fructose corn syrup, maltodextrin, and sugar mixtures.

Sugar bowl
The product we identify as "sugar" (without the plural) is highly refined sucrose, obtained primarily from sugar cane or sugar beets, that has been clarified, decolorized and concentrated to 99.9% sucrose. Sugar is inexpensive and readily available in a range of forms - granulated, powdered and liquid.

Each of these general forms comes in a range of variations: granulated or powdered in different particle sizes, liquid inverted to various degrees and brown sugars of different hues. Granulated and powdered sugars are white, but washed raw-sugar crystals are available as off-white turbinado sugar consisting of more than 99% sucrose. Brown sugar consists of fine sugar crystals coated with various hues of molasses-flavored syrup. These are numbered (6, 8, 10, 13), with color and flavor levels increasing with the number. Invert sugar is a non-crystallizing syrup made by hydrolyzing the disaccharide sucrose to its monosaccharide constituents, fructose and glucose. Refiners also make liquid syrups that contain a range of 100% uninverted to completely inverted grades. Sucrose, regardless of origin, is considered "generally recognized as safe (GRAS)" by the FDA and, like most carbohydrates, provides 4 kcal/gram.

In general, natural markets regard refined sucrose as "too processed," this has opened another sugar industry targeted at these markets. Less-refined sugar appears on labels as "unrefined sugar" or "evaporated cane juices." These single-crystallization sugars differ in flavor profile and particle size, and include products such as milled cane sugar, Demerara and Muscovado. Milled cane sugar, which includes some organic brands, is golden tan in color, with a slight molasses flavor. Demerara has a larger grain, is darker in color and definitely tastes of molasses. Muscovado is dark-brown and fine-grained with a heavy molasses flavor. The natural market also carries dry mixtures of sucrose and molasses. It is generally believed that these less-processed alternatives provide more nutrition and trace minerals, and this varies according to the product.

Molasses, the concentrated liquid extract of the sugar-refining process, has been used since 325 B.C. in baking and confectionery products. Molasses can be extracted from cane or beets, but foods primarily use sugar-cane-derived molasses. Domestic molasses (also known as mill molasses) comes from Florida, Texas or Louisiana, and can be found in five different grades:

• Whole-juice molasses has been clarified and evaporated to 79.5% solids. This is relatively harsh in flavor and dark in color.
• First molasses comes from the first extraction of sugar from the mother liquor and has a darker color than whole juice.
• Second molasses is a byproduct of second extraction with a darker, stronger flavor.
• Third molasses is a byproduct of third extraction, again darker and bitter.
• Final molasses does not allow for additional sugar to be extracted. This is the darkest and strongest in flavor.

While the various types of liquid molasses all contain 79.5% solids, a dry form also can be found at 96% solids. Final sugar in these products ranges from 53% to 74%, with 19% to 42% as invert sugar. Molasses, depending on the grade, supplies 70% to 100% of the sweetness of sucrose, as well as color, natural flavor or flavor enhancement, and additional calcium, iron, magnesium and potassium. Other properties are humectancy, water-activity (Aw) control and antioxidant properties. Molasses also can be used to "paint" other sweeteners to produce a brown sugar without lumping.

Saccharide selections
Consumers accept fructose, a major component of fruit pastes, as a natural product. Its relative sweetness compared to sucrose's 1.0, is 1.1 to 1.4, and it has sweetness synergies with sucrose. Fructose has a caloric value of 4 kcal/gram. It provides higher sweetness, so that less can be used to arrive at similar sweetness. Fructose's crystalline forms include granular or powdered, and it is made in liquid form as a component of high fructose corn syrup.

Fructose has a lower glycemic index (GI) value, a relative measure of the increase in plasma glucose following consumption. Consider the following GI values: glucose, 100; maltose, 105; sucrose, 60; and fructose, 20.

Since fructose is first absorbed in the small intestine, then transported to the liver for conversion to glucose, its initial uptake is insulin independent. Diabetics must manage their diet to maintain a normal blood glucose level - any increases in blood glucose will trigger an insulinemic response, creating an imbalance. This could lead to a serious insulin reaction or coma. Fructose does not cause a high initial glucose spike, keeping insulin at a normal level. High-fructose syrups at about 70% to 75% solids are composed of 42% fructose (52% dextrose) or 55% fructose (40% dextrose). Both are used extensively in the beverage and baking industries.

Other simple sugars to consider are dextrose and maltose. Maltose is less sweet but, as a disaccharide of dextrose, it provides more energy to the body during exercise (higher plasma glucose response) without increasing osmolality to the same degree as dextrose. As polymer size increases, various degrees of sweetening may also be obtained from corn syrup or corn syrup solids (26 DE to 63 DE) or from maltodextrins (0 DE to 20 DE). These would be classified as "sugars," with a caloric value of 4.0, but they provide inexpensive sources of carbohydrate energy and also serve as binders, bulking agents, humectants and Aw controls.

Polyols
Another group of nutritive sweeteners are referred to as sugar alcohols, or polyols. The polyols are excluded from the term "sugars" on a food's ingredient legend, and are instead labeled as "sugar alcohols" at about 70% to 75% solids, according to Title 21 of the Code of Federal Regulations (CFR) 101.9. Sugar alcohols are slowly absorbed, primarily in the small intestine, resulting in a lowered caloric value as well as a lowered glycemic and insulinemic response. More information on this is available from The American Dietetic Association ("Position of The American Dietetic Association: Use of Nutritive and Non-Nutritive Sweeteners," Journal of the American Dietetic Association 1998; 98: 580-587).

The polyols include sorbitol, mannitol, xylitol, erythritol, lactitol, isomalt, maltitol and liquid hydrogenated starch hydrolysates (HSH) and maltitol syrups. According to Peter Jamieson, developmental technologist, SPI Polyols, Inc., New Castle, DE, "Polyols are used extensively in the place of sucrose in sugar-free confectionery, chewing gum, baked goods, and dairy products. They are sugar-free, reduced-calorie, low-glycemic response and non-cariogenic. The FDA has allowed a health claim under Title 21 CFR 101.80 to note that sugar alcohols do not promote dental cavities. Xylitol is in fact anti-cariogenic, and is used extensively in oral care for that purpose."

HSH and maltitol syrups act as binders and humectants in many nutritional bars, and either maltitol and/or xylitol can be found in the chocolate coatings. Because they can be added to sugar-free products, the polyols are used in products for diabetics, but also have been recognized by athletes and physicians as a way to increase carbohydrate content with less of a caloric effect. (For more information on polyols, see "Polyols as Functional Ingredients with Multiple Uses," Cereal Foods World September 2000.)

Other natural sweeteners
Used in many "healthy" products for a variety of reasons, honey is a unique natural mixture of carbohydrates and other substances (38.2% fructose, 31.0% glucose, 17.1% water, 7.2% maltose, 4.2 % trisaccharides and other higher carbohydrates, 1.5% sucrose, and 0.5% minerals, vitamins and enzymes according to USDA data). Honey contains antioxidants, with higher levels in darker-colored floral honey, and enzymes, such as invertase, amylase, glucose oxidase and catalase. Its color can range from water-white to dark amber. The Aw of honey varies between 0.5 and 0.6 in the 40° to 100° F temperature range.

The National Honey Board, Longmont, CO, has published information on use of honey in juice beverages and yogurt shakes. In these applications, honey enhances sugar and fruit sweetness, and decreases sourness and bitterness. The studies show that honey also can enhance the growth of several Bifidobacterium species, establishing it as a prebiotic. Natural products often use brown rice syrups because organic-certified syrups can be sourced easily, and syrups or syrup solids are obtainable from 26 DE to 70 DE. These syrups are produced from brown rice - rice is known for its hypoallergenic properties, as well as for its use in gluten-free products for those with celiac disease. Rice-syrup applications are similar to those for corn syrups, but they do cost more per pound than an equivalent corn product.

Malt syrups and extracts are GRAS ingredients derived from germinated barley that has been steeped, dried, ground, extracted, filtered and evaporated to about 80% solids. These brown, sweet liquids may or may not contain diastatic enzymes. A range of products exists with various solids content, enzymatic activity, color, pH, reducing sugar level, protein and ash. Choice depends on formulation and finished product needs, such as high sweetness, a stickiness level that can be tolerated or desired binding characteristics. The saccharide profile ranges from about 1% to 2% fructose, 7% to 10% glucose, 1% to 3% sucrose, 39% to 42% maltose, 10% to 15% maltotriose and 25% to 30% higher saccharides.

Another sweetener, trehalose, was introduced in the United States in May 2000 by Cargill Inc., Minneapolis and Hayashibara Company Ltd., Japan. Trehalose, self-affirmed GRAS, is a disaccharide consisting of a, a-1,1-linked glucose molecules (maltose is a-1,4-linked). It has 45% the sweetness of sucrose (equivalent to maltose), is non-reducing with low hygroscopicity and fully caloric.

At the 2000 Calorie Control Council Technical Meeting in Newport Beach, CA, Arla Foods, Denmark, reported the commercialization of tagatose, also known as D-tagatose, a carbohydrate derived from whey. Research has indicated that caloric value is about 1.5 kcal per gram, and the product may have a lowered glycemic impact.

Fruit mixtures or concentrates also can sweeten healthful foods, ingredients such as dried plums, raisin-juice concentrate or cherry-juice concentrate. There are a large number of product sources, but care must be taken to find products with the proper mixture of sugars and other inherent components to provide the right flavor profile, Aw, viscosity and humectant properties.

Many fruit products - dry, concentrates, purée and juices - sweeten natural foods and other health-oriented products. Dried plums, for example, contain 8.1% total dietary fiber (mostly pectin), 16.5% sorbitol and 1.57% malic acid (great for flavor enhancement), according to the California Dried Plum Board, Pleasanton, CA. They also supply brown color, antimicrobials, binding properties, humectancy (sorbitol), as well as sweetness, which gives those looking for a cleaner label a more-natural option than ingredients with chemical-sounding names. Concentrates of raisin juice and cherry juice contribute color, sweetness, flavor and humectancy to healthful foods. Cherry-juice concentrate is derived by evaporating tart cherries to 68ºBrix. At this level of solids, it contains about 34% glucose and 20% fructose, plus natural anthocyanins and antioxidants. Raisin-juice concentrate, at 70% solids, contains 65% sugars, soluble fibers and antioxidants.
Another juice concentrate seen in some natural and organic products is agave nectar. This juice, obtained from blue agave, also is the source of tequila. However, this use conflicts with agave for sweetener use as far as supply; for both of these, source and quality is important. Agave nectar is sold at 75°Brix, and contains 92% fructose and 8% glucose, so the sweetness of the nectar is similar to that of fructose.

Non-nutritive sweeteners
The non-nutritive sweeteners, also referred to as non-caloric, are either inherently acaloric (zero calories), or are fully caloric with sweetness potencies so high that their extremely low usage levels have no significant impact on a product's final caloric content. They are indispensable in formulating sugar-free, reduced-calorie foods.

Along with the higher potency comes a higher price, but using these sweeteners at flavor-type levels dilutes the price impact. The non-caloric sweeteners are widely used for weight loss, diabetic products and caries prevention although natural-food stores don't generally favor them since they don't fit the "natural" image. The U.S.-approved list includes aspartame, sucralose, acesulfame-K, saccharin, and elsewhere in the world, cyclamates, stevia, thaumatin, and alitame are used.

Saccharin was the first low-calorie sweetener used, and has been in use for more than 100 years. It is low in cost, claims 200 times the sweetness of sucrose and is acaloric. Saccharin currently is approved in more than 100 countries, but has been much maligned due to early studies showing bladder tumors in rats. Because of those studies, the FDA proposed a ban on its use in 1977 (withdrawn in 1991), but Congress imposed a moratorium on this ban effective through May 2002. Through the efforts of the Calorie Control Council, Atlanta, and other organizations, saccharin's support continually grows. In 2000, the National Toxicology Program delisted saccharin from its "9th Report on Carcinogens," stating "studies now indicate that the rat bladder tumors arise from mechanisms that are not relevant to the human situation. In addition, we have decades more data from observations of humans using saccharin that adds to our confidence. In other words, with better science, we can now make a better call." After reviewing more than 30 human studies, the Joint Expert Committee on Food Additives (JECFA) doubled the Acceptable Daily Intake (ADI), stating, "adverse findings observed in male rats fed extremely high doses of sodium saccharin are not relevant to man." This led toward removing restrictions and labeling disadvantages, which have hampered the U.S. saccharin use.

On Dec. 21, 2000, President Clinton signed the HHS Appropriations Bill (H.R. 4577), which contained the Saccharin Warning Elimination via Environmental Testing Employing Science and Technology - or "Sweetest" Act (H.R. 5668). This effectively removed the requirement for the saccharin warning label.
Cyclamate, a calorie-free sweetener discovered in 1937, is 30 to 50 times sweeter than sucrose. It is metabolized to a limited extent in some individuals, but generally is excreted unchanged. It comes in two forms - sodium cyclamate or calcium cyclamate - both of which exhibit stability to both high and low temperatures and has a pleasant, sweet taste profile.

Cyclamate is approved in more than 50 countries worldwide, including the EC. However, the United States banned cyclamate in 1970, and some countries restricted its use due to the development of bladder tumors in rats fed the sweetener. But the result of this study has been called into question and the JECFA has determined human cyclamate use is safe and has established a safe human consumption level. A petition for the re-approval of cyclamate is currently under review by the FDA. (In 1984, FDA's Cancer Assessment committee reviewed the scientific evidence and said the following: "the collective weight of the many experiments . . . indicates that cyclamate is not carcinogenic.")

Another, high-intensity sweetener, aspartame, is a dipeptide (methyl ester of aspartic acid and phenylalanine), and is actually fully caloric with 4.0 kcal/ gram. However, at 160 to 220 times sweeter than sucrose, these calories have no impact on the final product. Aspartame, after a rocky start due to the saccharin/cyclamate problems noted above, also benefited by these problems encountered by the other two sweeteners. In 1981, the FDA approved aspartame, with only a warning label advising phenylketonurics that the ingredient contained phenylalanine. It quickly became the most popular low-calorie sweetener and, after slowly gaining U.S. approvals step-by-step through categories, was approved in 1996 as a general-purpose sweetener. In addition to the United States, aspartame can be found in products throughout Eastern and Western Europe, Canada, South America, Australia and Japan.

Aspartame, now available from several suppliers, is used primarily in soft drinks, but food and beverage manufacturers use the sweetener in thousands of other products. Aspartame, although a good all-purpose sweetener, does break down under high temperature, pH and moisture.

The NutraSweet Company, Mt. Prospect, IL, also is seeking approval of neotame, produced by the hydrogenation of aspartame and 3,3-dimethylbutyraldehyde (aldehyde). Like aspartame, this is a protein, but is 10,000 times sweeter than sucrose.

In 1988, the FDA approved acesulfame-K for chewing gum, dry mixes for beverages, instant coffee and tea, gelatin, puddings, non-dairy creamers and tabletop sweeteners. In 1998, this acaloric sweetener that is approximately 200 times sweeter than sucrose was approved for liquid beverages.

Acesulfame-K is approved for a variety of uses in approximately 90 countries, including the USA, the EC, Canada and Australia. The body doesn't metabolize this sweetener; the kidneys excrete it unchanged. It doesn't promote tooth decay and is suitable for formulating diabetic products.

The marketing of acesulfame-K was first to aggressively incorporate the multiple sweetener approach proposed for years by the Calorie Control Council. By itself, acesulfame-K has a bitter, metallic aftertaste, but it acts in synergy with other sweeteners, notably aspartame, and also remains stable at high temperatures.
The high-potency sweeteners display different sweetness profiles in terms of time to maximum intensity and duration of sweetness. Many (including acesulfame-K and aspartame) complement each other in profile so that blends (about 1:1) produce more sweetness and an overall profile more similar to sucrose. The user's benefits are lower cost and better sweetness quality.

Sucralose was approved in 1998 in the United States (also approved in over 30 countries) as a tabletop sweetener and for use in desserts, confections and non-alcoholic beverages. Sucralose is derived from sucrose, is acaloric, and is about 600 times sweeter than sucrose. The EC set an ADI of 15 mg/kg in September 2000. Sucralose has a very good sweetness profile, and is very stable in aqueous food systems. Sucralose seems to have gained some momentum within "natural- type" foods, and is on the Center for Science in the Public Interest's (CSPI) "acceptable" list. Again, perception is key, and the precursor for sucralose is sucrose, which lends it a more natural cachet than many of the other high-intensity sweeteners.

Thaumatin is an interesting sweetener extracted from katemfe fruit. Thaumatin (known commercially as Talin™) is a protein 2,000 to 2,500 times sweeter than sucrose, although with a delayed taste onset. It can produce a licorice-like aftertaste at high levels. It is heat- and acid-stable and synergistic when combined with other high-potency sweeteners. It does not promote tooth decay and no adverse reactions have been observed in the animal and human studies conducted.

Thaumatin is authorized in the EC for use in foods as a sweetener, as a flavor enhancer in chewing gum, beverages and desserts, and in all applications as a "flavor preparation." The FDA has not approved it for use as a food sweetener. However, it has been approved by the Flavor & Extract Manufacturers' Association of the U.S. (FEMA) as a flavor enhancer at levels of 0.1 to 0.5 ppm. At these levels it enhances sweet and savory flavors, and masks bitter and metallic aftertastes. It has similar flavor-use approval elsewhere around the globe, including Canada, Japan and Australia.

Another sweetener of interest is stevioside. Steviosides are glycosides present in the stevia plant's leaves. Stevioside is approximately 100 to 150 times sweeter than sugar, but also has a licorice-like aftertaste. Discovered in Paraguay, it is sold as a dietary supplement in the United States, but is not approved as a sweetener here or in Europe. In 1999, JECFA and the EC evaluated studies on the sweetener and determined it was unacceptable for use as a sweetener in food.

Science on sugar
Any sweetener - nutritive or non-nutritive - can be used in a "healthy" food. As mentioned before, the only restrictions are in the end use and in the "mind of the market."

While speaking at the Intertec Sweeteners 2000 Conference in Reston, VA, David Ropa, vice president, TJP Market Development, Madison, WI, stated that nutritive-sweetener consumption has increased 16% over the past two decades, half of that percentage within the past five years (these figures vary according to source). Part of this may be due to a change in the FDA's view of non-nutritive sweeteners. In 1980, the FDA stated that the use of non-nutritive sweeteners in confectionery was not for a functional purpose - their presence meant adulteration. In 1993, this was reversed, allowing their use in confectionery.

According to Ropa, the current market is torn between a view that nutritive sweeteners cause weight gain and a view that they do not cause weight gain. The former view increases the demand for non-nutritive sweeteners as well as encourages a move toward elimination of carbohydrates from the diet, or increasing protein vs. carbohydrate. The latter is supported by epidemiological studies that show an inverse relationship between sugar intake and obesity while a direct relationship exists between obesity and fat intake.

The USDA "Dietary Guidelines for Americans" now recommends the use of sugars in moderation. This reflects a much more relaxed view toward sugars, supported by a number of studies that generally fail to link sugars directly with disease. The one exception to this statement is their role in dental caries.

According to the International Food Information Council Foundation's (IFIC) 1995 IFIC Review on "Sweet Facts About Sugars and Health," studies support the view that sugars do not affect the mental performance or behavior of children; they do not stimulate appetite in normal healthy adults or children, leading to obesity; they do not cause diabetes mellitus when consumed in moderation; and they do not cause coronary heart disease in normal individuals. This is the message that should be communicated to consumers.

Special market needs
For diabetics, the American Diabetes Association no longer puts sugar off-limits, but does recommend moderation. (Diabetics must substitute sugar for other foods containing carbohydrates.) Alternative sweeteners can be a good choice for those targeting the market. The American Dietetic Association states: "Although it is recognized that carbohydrate sources provide different glycemic responses, the clinical perspective is that attention should be given first to the total amount of carbohydrate consumed rather than the source of the carbohydrate." Within this, dietetics practitioners can use both nutritive and non-nutritive sweeteners as part of the overall plan. Obesity is not the result of sugar consumption - overall caloric intake must be balanced with proper exercise. Reduced calorie and non-caloric sweeteners can certainly help in the overall plan by reducing total calories.

If the goal is cavity prevention, according to the American Dietetic Association, "use of polyol-based gum can reduce the risk of dental caries compared to sucrose-sweetened gum, with the greatest benefit from xylitol-based gums." In fact, the FDA allows the health claim "does not promote tooth decay" if the sugar alcohol in the food is xylitol, sorbitol, mannitol, maltitol, isomalt, lactitol, hydrogenated starch hydrolysates, hydrogenated glucose syrup, erythritol, or a combination of these. The food also must be sugar-free (less than 0.5 grams of sugar per reference amount) and the food must not lower plaque pH less than 5.7 by bacterial fermentation during consumption or for up to 30 minutes as measured by in vivo testing.

For sports products (see "Beverages and Bars Provide Nutritional Replenishment," in the September 2000 Functional Foods Annual issue of Food Product Design), the choice in sweeteners is dependent upon the goal. Should the product deliver quickly assimilated glucose (as in an energy beverage to be consumed during competition), or should this be delayed (as in a high-protein diet product which emphasizes insulin regulation)? Is carbohydrate loading the goal (as in pre-competition products), and what about calories? Does the sweetener need to act as a binder?

The product developer looking to design products for today's health-conscious consumer has a number of choices as their disposal. Choosing the right sweetening agent will lend to the overall success of a product, be it for weight loss, general nutrition or disease control.

Ronald C. Deis, Ph.D., is the director, product and process development at SPI Polyols, Inc., New Castle, DE. Deis has 20 years of experience in the food industry, both in food ingredients (starches, polyols, high potency sweeteners, bulking agents) and in consumer product companies (cookies, crackers, soups, sauces). He has been a shortcourse speaker (polyols, fat replacers) and a freelance writer on a number of food science related subjects in food journals and has contributed chapters on sweeteners and fat replacers for several books.

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