Drawings in Egyptian tombs depicting beekeeping practices and honey production attest that the demand for sweet-tasting Page 1587  |  Top of Article
TABLE 1. SUGAR CONSUMPTION PER CAPITA PER YEAR International Sugar Organization substances dates back to 2600 B.C. Sugar consumption varies considerably from one country to the next as shown in Table 1.

In terms of sugar consumption in the United States, until the early 1940s, sucrose from sugarcane and sugar beets accounted for a very high volume of the fundamental sweeteners. Since that time, there has been continuously increasing consumption of corn sweeteners and other caloric sweeteners, notably high-fructose corn syrup (HFCS). Of course, a marked impact on sucrose consumption occurred with the introduction of artificial sweeteners, particularly of saccharin and aspartame. Sweeteners fall into two general categories—nutritive and nonnutritive.

In addition to their sweetening power, nutritive sweeteners are effective preservatives in numerous foods. Sweeteners tie up water, essential for microorganism growth, thus preventing or inhibiting spoilage. Nutritive sweeteners also serve as food for yeasts and other fermenting agents, so important in many processes, including baking. The principal functional properties of sucrose are (1) browning reactions, (2) fermentability, (3) flavor enhancement, (4) freezing-point depression, (5) nutritive solids source, (6) osmotic pressure, (7) sweetness, (8) texture tenderizer, and (9) viscosity/bodying agent.

Among the principal natural sugars are fructose, glucose (also called dextrose), honey, invert sugar, lactose, maltose, raffinose and stachyose, sucrose, sugar alcohols, and xylitol.

Dextrose Equivalent. A means for comparing one sugar with another. The total amount of reducing sugars, expressed as dextrose (glucose), that is present in a given sugar syrup is calculated as a percentage of the total dry substance. More technically, the dextrose equivalent (DE) is the number of reducing ends of sugar that will react with copper. The DE can be measured in several ways.

Fructose. Also called levulose or fruit sugar, C₆H₁₂O₆. It is the sweetest of the common sugars, being from 1.1 to 2.0 times as sweet as sucrose. Fructose is generally found in fruits and honey. An apple is 4% sucrose, 6% fructose, and 1% glucose (by weight). A grape (Vitis labrusca) is about 2% sucrose, 8% fructose, 7% glucose, and 2% maltose (by weight) (Shallenberger). Commercially processed fructose is available as white crystals, soluble in water, alcohol, and ether, with a melting point between 103 and 105°C (217.4 and 221°F) (decomposition). Fructose can be derived by the hydrolysis of insulin; by the hydrolysis of beet sugar followed by lime separation; and from cornstarch by enzymic or microbial action.

Dry crystalline fructose is reported to have a sweetness level of 180 on a scale in which sucrose is represented at 100 (Andres, 1977). In cool, weak solutions and at lower pH, sweetness value is reported to be 140-150. At neutral pH or higher temperatures, the sweetness level drops, and at 50°C (122°F) sweetness equals that of a corresponding sucrose solution. A synergistic sweetness effect is reported between sucrose and fructose. A 40-60% fructose/sucrose mixture in a 100% water solution is sweeter than either component under comparable conditions (Unpublished report, University of Helsinki, 1972).

Glucose. Also known as grape sugar or dextrose, this is the main compound into which other sugars and carbohydrates are converted in the human body and thus is the major sugar found in blood. Glucose is naturally present in many fruits and is the basic “repeating” unit of the starches found in many vegetables, such as potato. Purified glucose takes the form of colorless crystals or white granular powder, odorless, with a sweet taste. Soluble in water, slightly soluble in alcohol. Melting point is 146°F (294.8°F). Glucose finds many uses—confectionery, infant foods, brewing and winemaking, caramel coloring, baking, and canning. Glucose is derived from the hydrolysis of corn starch with acids or enzymes. Glucose is a component of invert sugar and glucose syrup. Glucose was first obtained (1974) from cellulose by enzyme hydrolysis.

Corn (maize) syrup is a sweetener derived from corn starch by a process that was first commercialized in the 1920s. Corn syrup is composed of glucose and a variety of sugars described as the “maltose series of oligosaccharides.” These syrups are not as sweet as sucrose, but are very often used in conjunction with sugar in confections and other food products.

Five types of corn sweeteners are commercially available: (1) Corn syrup (glucose syrup), with a DE of 20 or more, is a purified and concentrated aqueous solution of mono-, di-, and oligosaccharides. High fructose corn syrup (HFCS) is prepared by enzymatically converting glucose to fructose with glucose isomerase. (2) Maltodextrin, concentrated solutions or dried powders of disaccharides, characterized with a DE of less than 20. The manufacturing process is similar to that of corn syrup except that the conversion process is stopped at an earlier stage. (3) Dried corn syrup is a granular, crystalline, or powder product, from which a portion of the water has been removed. (4) Dextrose monohydrate is a purified and crystallized form of D-glucose, and contains one molecule of water of crystallization per molecule of D-glucose. (5) Dextrose anhydrous is primarily D-glucose with no water of crystallization.

Galactose. A monosaccharide commonly occurring in milk sugar or lactose. Formula, C₆H₁₂O₆.

Honey. A natural syrup which varies in composition and flavor, depending upon the plant source from which the nectar was collected by the honeybee, the amount of processing, and the duration of storage. The principal sugars contained in honey are fructose and glucose, the same components as in table sugar. There are minute amounts of vitamins and minerals in honey, but these are not usually considered in terms of calculating minimum requirements.

Invert Sugar. A mixture of 50% glucose and 50% fructose obtained by the hydrolysis of sucrose. Invert sugar absorbs water readily, and is usually only handled as a syrup. Because of its fructose content, invert sugar is levorotatory in solution, and sweeter than sucrose. Invert sugar is often incorporated in products where loss of water must be minimized. Commercially, invert sugar is obtained from the inversion of a 96% cane sugar solution. This sugar is used in various foods, in the brewing industry, confectionery field, and in tobacco curing.

Lactose. Milk sugar or saccharum lactis, C₁₂H₂₂O₁₁ · H₂O. Purified lactose is a white, hard, crystalline mass or white powder with a sweet taste, odorless. It is stable in air, soluble in water, insoluble in ether and chloroform, very slightly soluble in alcohol. The compound decomposes at 203.5°C (398.3°F). Lactose is derived from whey, by concentration and crystallization. Cow's milk contains about 5% lactose. Because of its relative lack of sweetening power, lactose is not considered a sweetener in the usual sense. It is used as a bulking agent in numerous food products. Lactose can be used effectively as a carrier for artificial sweeteners to give a free-flowing powder that is easily handled. There has been interest in the hydrolysis of lactose into glucose and galactose, both enzymatically and chemically. It has been reported that glucose and galactose are known to be sweeter than lactose itself. The relative sweetness of sugars is not a constant relationship, but depends upon many factors, including pH, temperature, and presence of other constituents. Mixtures of sugars can make a different sweetness impression than that of individual sugars alone. Synergistic sweetness often results from a combination of sugars.

Maltose. Also known as malt sugar, maltose is a product of the fermentation of starches by enzymes or yeast. Barley malt, which is used as an adjunct in brewing, enhances the flavor and color of beer because of its maltose content. Maltose also is formed by yeast during breadmaking. Maltose is the most common reducing disaccharide, C₁₂H₂₂O₁₁ · H₂O, composed of two molecules of glucose. It is found in starch and Page 1588  |  Top of Articleglycogen. Purified maltose takes the form of colorless crystals, melting point, 102-103°C (215.6–217.4°F). Soluble in alcohol; insoluble in ether. Combustible. Maltose is used as a nutrient, sweetener, and culture medium.

Raffinose and Stachyose. These are sugars found in significant amounts in some foods, such as beans. These sugars are not digested in the stomach and upper intestine as are other disaccharides. They are fermented by bacteria in the lower digestive tract, producing gases and sometimes causing discomfort from flatulence. Raffinose is a trisaccharide composed of one molecule each of D(+)-galactose, D(+)-glucose, and D(−)-fructose, C₁₈H₃₂O₁₆ · 5H₂O. Raffinose is sometimes used in the preparation of other saccharides.

Sucrose. Table sugar, also known as saccharose. Sucrose is a disaccharide, composed of two simple sugars, glucose and fructose, chemically bound together, C₁₂H₂₂O₁₁. Hard, white, dry crystals, lumps, or powder. Sweet taste, odorless. Soluble in water; slightly soluble in alcohol. Solutions are neutral to litmus. Decomposes in range of 160-186°C (320-366.8°F). Combustible. Optical rotation = +33.6°. Derived from sugarcane or sugar beets and also obtainable from sorghum. Sucrose is the most abundant free sugar in the plant kingdom and has been used since antiquity (Mead and Chem, 1977).

Turbinado sugar is raw sugar that has been refined to remove impurities and most of the molasses. It is edible when produced under sanitary conditions and has a molasses flavor. Brown sugar consists of sucrose crystals covered with a film of molasses syrup that give the characteristic color and flavor. The sucrose content varies from 91 to 96%. Confectioner's or powdered sugar is another form of sucrose made by grinding the sugar crystals. It is usually mixed with about 3% starch to prevent clumping. It is used for household baking, canning, and table use, or industrially where rapid solution in cold liquids is desirable.

Sugar Alcohols. These are polyols, chemically reduced carbohydrates. Important in this group are sorbitol, mannitol, maltitol, and xylitol. Xylitol is described later.

Polyols are frequently used sugar substitutes and are particularly suited to situations where their different sensory and functional properties are attractive. In addition to sweetness, some of the polyols have other useful properties. For example, although it contains the same number of calories/gram as other sweeteners, sorbitol is absorbed more slowly from the digestive tract than is sucrose. It is, therefore, useful in making foods intended for special diets. When consumed in large quantities (1-2 oz; 25,059 g)/day, sorbitol can have a laxative effect, apparently because of its comparatively slow intestinal absorption.

When sugar alcohols are ingested, the body converts them first to fructose, which does not require insulin to facilitate its entry into the cells. For this reason, ingesting these sweeteners (including fructose itself) does not cause the immediate increase in blood sugar level which occurs upon eating glucose or sucrose. Within the body, however, the fructose is rapidly converted to other compounds, which do require insulin in their metabolism. One effect of this stepwise metabolism is to “damp out” the peaks in blood sugar levels which occur immediately after ingesting sucrose, but which are absent after ingesting fructose, even if the eventual insulin requirements are the same. Thus, individuals with metabolic problems should not make the assumption that fruit sugars are perfectly all right to consume, but first should consult their physicians. In fact, some health scientists are dubious about pursuing the apparent claims for substituting fructose and sugar alcohols for sucrose as a major sweetener, particularly for diabetics, until more research is done on their long-range nutritional and biophysiological consequences. Research interest has also focused on these sweeteners because of their relatively low potential for causing dental caries. Studies have shown about a 30% reduction in dental caries in laboratory animals on sorbitol and mannitol diets, and virtually complete elimination of caries in the animals when on xylitol diets.

Xylitol. This is a 5-carbon sugar alcohol that occurs widely in nature—raspberries, strawberries, yellow plums, cauliflower, spinach, and many other plants. Although widely distributed in nature, it is present in low concentrations and this makes it uneconomic to extract the substance directly from plants. Thus, commercial xylitol must be produced from xylan or xylose-rich precursors through the use of chemical, enzymatic, and other bioprocessing conversions. A frequently used source has been birch tree chips. Other appropriate starting materials include beech and other hardwood chips, almond and pecan shells, cottonseed hulls, straw, cornstalks (maize), and corn cobs. The base source in the aforementioned agricultural waste materials is hemicellulose xylan. The hemicellulose is acid hydrolyzed to yield xylose which, followed by hydrogenation and chromatographic separation, yields xylitol.

Xylitol is equally as sweet as sucrose. This property is of advantage to food processors because in reformulating a product from sucrose to xylitol, approximately the same amounts of xylitol can be used. Because xylitol has a negative heat of solution, the substance cools the saliva, producing a perceived sensation of coolness, quite desirable in some food products, notably beverages. Recently, this property has been used in an iced-tea-flavored candy distributed in the European market. As of the late 1980s, 28 countries have ruled positively in terms of xylitol for use in commercial products. Xylitol has been found particularly attractive for use in chewing gum, mint and hard candies, and as a coating for pharmaceutical products. Xylitol has the structural formula shown below, with a molecular weight of 152.1. It is a crystalline, white, sweet, odorless powder, soluble in water and slightly soluble in ethanol and methanol. It has no optical activity.

Isomalt. Developed in Germany, isomalt is described as an energy-reduced bulk sweetener and marketed in Europe under the tradename Palatinit™mark. The compound is produced from sucrose in a two-step process, as shown in Fig. 1.

Nutritive Sweeteners

In the first step, the easily hydrolyzable 1-2 glucoside linkage between the glucose and fructose moieties of sucrose are catalyzed by immobilized enzymes to produce isomaltulose, Palatinos.™ mark After crystallization, the isomaltulose is hydrogenated in a neutral aqueous solution using a nickel catalyst.

It is claimed that isomalt is odorless, white, crystalline, and sweet tasting without the accompanying taste or aftertaste. Sweetening power is from 0.45 to 0.6 that of sucrose. A synergistic effect is achieved when isomalt is combined with other artificial sweeteners and sugar substitutes. Principal applications are in confections, pan-coated goods, and chewing gum. The substance was approved for use in most European countries in 1985. Classification of isomalt as a GRAS substance was petitioned in the United States. (GRAS = generally regarded as safe.)

Aspartame. This synthetic sweetener is included with the nutritive sweeteners because it does have some caloric value (when metabolized as a protein, it releases 4 kcal/g). The relationship between sweetness of aspartame and sucrose is almost linear when plotted on a log-log scale. Aspartame is 182 times sweeter than a 2% sucrose solution, but only 43 times sweeter than a 30% solution. The clean, full sweetness of aspartame is similar to that of sucrose and complements other flavors.

The full name of aspartame is aspartylphenylalanine, a dipeptide that degrades to a simple amino acid. It has been reported as easily metabolized by humans. Aspartame was accidentally discovered in 1965 with the synthesis of a product for ulcer therapy. Aspartame is metabolized by the same biochemical pathway as proteins, yielding phenylalanine, aspartic acid, and methanol. Because of the byproduct phenylalanine, which some individuals are unable to metabolize, appropriate labeling is required. This is a concern for individuals with phenylketonuria (PKU). Aspartame was first approved in the United States in 1974, then banned in 1975. In July of 1981, it was approved for use in various foods, dry beverage mixes, and in tabletop sweeteners. Approval for use in carbonated beverages was granted in July 1983.

Currently, aspartame is used in tabletop sweeteners (Equal in the U.S.; Egal in Quebec, Canada; and Canderal in Europe and the U.K.). Aspartame currently is incorporated as the exclusive sweetening ingredient in nearly all diet soft drinks in the United States. In other countries, it may be blended with saccharin at a level close to 50% of the saccharin level. Soft-drink manufacturers have taken some measures to enhance stability by raising pH slightly and by more closely controlling the inventory for carbonated soft drinks. Notable differences in sweetness are perceived at a 40% loss in aspartame level.

Crystalline Maltitol. Classified as a bulk sweetener with taste and mouthfeel similar to sucrose, crystalline maltitol contains maltitol as the major component (88+%), with small amounts of sorbitol, maltotriitrol, and hydrogenated oligosaccharides. Its use is in tabletop sweeteners, chocolate, candy, and baked goods. Maltitol has been a major component of hydrogenated glucose syrup in the United States since 1977 and has been Page 1589  |  Top of Article
Fig. 1. Isomalt used in Japan since 1963. The product was introduced in Europe in 1984. Classification of crystalline maltitol as a GRAS substance was petitioned in the United States in 1986.

There are several currently used and a number of potential noncaloric sweeteners, including saccharin, cyclamate (banned in the U.S., but permitted in approximately 40 other countries), acesulfame K, monellin (from the serendipity berry), stevioside, glycyrrhizin, hernandulcin, neosugar, miraculin (from miracle fruit), and a sweetener-enhancer, thaumatin, are being investigated.

Saccharin. A noncaloric sweetener that is about 300 times as sweet as sugar. The compound is manufactured on a large scale in several countries. It is made as saccharin, sodium saccharin, and calcium saccharin, as shown by formulas below.

Sodium saccharin
Calcium saccharin
Saccharin

Saccharin (ortho-benzosulfimide) was discovered in 1879 by I. Remsen and C. Fahlberg when they were researching the oxidation products of toluene sulfone amide. The most common forms of saccharin are sodium and calcium saccharin, although ammonium and other salts have been prepared and used to a very limited extent. The saccharins are white, crystalline powders, with melting points between 226 and 230°C (438.8 and 446°F). Soluble in amyl acetate, ethyl acetate, benzene, and alcohol; slightly soluble in water, chloroform, and ether. Saccharin is derived from a mixture of toluenesulfonic acids. They are converted into the sodium salts, then distilled with phosphorus trichloride and chlorine to obtain the ortho-toluene sulfonyl chloride, which by means of ammonia is converted into ortho-toluenesulfamide. This is oxidized with permanganate, then treated with acid, and saccharin is crystallized out. In food formulations, saccharin is used mainly in the form of its sodium and calcium salts. Sodium bicarbonate may be added to provide improved water solubility.

Saccharin is used in conjunction with aspartame in carbonated beverages. Other uses include tabletop sweeteners, dry beverage blends, canned fruits, gelatin desserts, cooked and instant puddings, salad dressings, jams, jellies, preserves, and baked goods.

For many years, saccharin has been under investigation by a number of countries. As of the late 1900s, some questions remained unresolved.

Cyclamate. Group name for synthetic, nonnutritive sweeteners derived from cyclohexylamine or cyclamic acid. The series includes sodium, potassium, and calcium cyclamates. Cyclamates occur as white crystals, or as white crystalline powders. They are odorless and in dilute solution are about 30 times as sweet as sucrose. The purity of commercially available compounds is approximately 98%.

Discovered in 1937 and patented in 1940, cyclamate is a derivative of cyclohexylamine, specifically, cyclohexane sulfonic acid. The sodium salt form is normally used, but the calcium salt may be substituted in low-sodium diets. See structural formulas below.

Sodium cyclamate
Calcium cyclamate
Cyclamic acid

Once widely used, cyclamate was prohibited in the United States in 1970. Although used in many other countries, reapproval in the United States has not yet been established. An independent review of the possible carcinogenicity of cyclamate was conducted in April 1985 by the National Academy of Sciences/National Research Council at the request of the Food and Drug Administration. The review concluded that cyclamate itself is not a carcinogen, although it may serve as a promotor or cocarcinogen in the presence of other substances.

Acesulfame-K. This substance (potassium salt of the cyclic sulfano-mide), 6-methyl-1,2,3-oxathiazine-4(3H)-1,2,2-dioxide, shown below, was developed by Karl Clauss (Hoechst Celanese Corporation, Somerville, New Jersey) in 1967. The compound is a white, odorless, crystalline substance with a sweetening power 200 times that of sucrose. A synergistic effect is produced when the substance is combined with a number of other sweeteners. The substance is calorie-free and not metabolized in the human body. Approval of the use of Acesulfame-K was given by the Food and Drug Administration (FDA) in the United States in 1983 and it is found in scores Page 1590  |  Top of Articleof popular retail products, including yogurt, rice pudding, and soft drinks.

Acesulfame-K

Sucralose. Developed in England during the mid-1980s, testing and evaluation commenced in 1988. The structural formula of the compound (a chlorinated disaccharide derived from sucrose) is shown below.

Sucralose

Sucralose is absorbed poorly in humans and other mammalian species. The small portion that is absorbed is not broken down and is quickly excreted. It has been reported that an extensive array of studies has demonstrated that sucralose is nontoxic—not carcinogenic, teratogenic, mutagenic, or caloric.

Monellin. The sweetness of this compound is claimed to be 1500 to 3000 times that of sucrose, but a different flavor profile prevails. The detection of a sweet taste is slow, commencing after a few seconds in contact with the taste buds, then gradually increasing to its peak intensity. The sweet taste can persist for up to an hour. The source is the relatively rare serendipity berry, the fruit of a noncultivated West African vine. Extraction of the sweet component is effected by treating the berry with a series of enzymes (pectinase and bromelain), followed by dialysis and chromatographic separation. The compound resulting contains the protein monoellin with a molecular weight of about 10,700 and composed of two nonidentical polypeptide chains of 50 and 43 amino acids. Neither of the individual chains imparts sweetness. Regulatory measures have not been instituted because of the compound's apparent instability and limited raw resources for processing. However, to date, tests with mice have shown no evidence of toxicity.

Stevioside. Derived from the roots of the herb Stevia rebaudiana, this compound has found limited use in Japan and a few other countries as a low-calorie sweetener having about 300 times the sweetening power of sucrose. The compound has not been investigated thoroughly by a number of countries with strong regulatory agencies and, therefore, is not on the immediate horizon for wide consideration as a sweetener.

The dried leaves of S. rebaudiana have been used in Paraguay for many years to sweeten bitter drinks. From 3 to 8% of the dried leaves is stevioside, which is a diterpene glycoside as shown by the formula below.

Stevioside

Glycyrrhizins. These are noncaloric sweeteners approximately 50 times as sweet as sugar and used as a flavor enhancer under the GRAS classification in the United States. Glycyrrhizins, which have a pronounced licorice taste, are used in tobacco, pharmaceuticals, and some confectionary products. They are available in powder or liquid form and with color, or as odorless, colorless products. These compounds are stable at high temperatures (132°C; 270°F) for a short time and thus can be used in bakery products. In some chocolate-based products, the sweetener has been used to replace up to 20% of the cocoa. The sweetener also has excellent foaming and emulsifying action in aqueous solutions. Typical products in which these sweeteners may have application include cake mixes, ice creams, candies, cookies, desserts, beverages, meat products, sauces, and seasonings, as well as some fruit and vegetable products. Generally available as malted and ammoniated glycyrrhizin.

The basic compound is a triterpene glycoside. It is extracted from the licorice root, of which the principal sources are China, Russia, Spain, Italy, France, Iran, Iraq, and Turkey. The roots, containing 10% moisture, are dried and shredded, after which they are extracted with aqueous ammonia, concentrated in vacuum evaporators, precipitated with sulfuric acid, and crystallized with 95% ethyl alcohol.

Hernandulcin. Tasting panels have estimated that this substance is 1000 times sweeter than sucrose, but the flavor profile is described as somewhat less pleasant than that of sucrose. Hernandulcin is derived from a plant, Lippia dulcis Trev, commonly known as “sweet herb” by the Aztecs as early as the 1570s. It has been categorized as noncarcinogenic, based upon standard bacterial mutagenicity tests. The economic potential is being studied.

Neosugar. This is another substance in early stages of development and testing. The compound is composed of sucrose attached in a beta(2-1) linkage to 2, 3, or 4 fructose units.

Miraculin. Rather than a sweet-tasting substance, miraculin is described as a taste-modifying substance that elicits a sweet taste to tart foods. The product has been reported as used by African cultures for over a century. The compound is derived from a shrub (Synsepalum dulcificum) which grows in West Africa. Miraculin is a glycoprotein with a molecular weight ranging from 42,000 to 44,000. Approval of the Food and Drug Administration has thus far been denied, awaiting further tests. A GRAS category was denied in 1974.

Thaumatin. This is a protein extracted and purified from Thaumato-coccus danielli, a plant that is found in West Africa. The leaves of the plant have been used for many years in Africa for wrapping food during cooking. Claims have been made that thaumatin is from 2000 to 2500 times sweeter than 8-10% solution of sucrose. The final product is odorless, cream-colored and imparts a lingering licorice-like aftertaste. The substance synergizes well with monosodium glutamate (MSG) and is used in typical Japanese seasonings as well as in chewing gum, pet foods, and certain pharmaceuticals (to mask unpleasant flavor notes). Use in Japan has been approved since 1979. It is considered a GRAS substance in the United States for use in chewing gum. In this application, thaumatin extends the flavor and boosts the perceived duration of flavor. The compound is normally applied as a dust to the surface of gum. Some authorities believe that the use of thaumatin in pet foods has high potential.

In using low-calorie sweeteners in various food products, the problems are not limited to flavor, but often much more importantly involve texture, acidity, storage stability, and preservability, among others. Acceptable nonnutritively sweetened products cannot be developed by the simple substitution of artificial sweeteners for sugars. Rather, the new product must be completely reformulated from the beginning. Three examples follow.

Jams, Jellies, and Preserves. Traditional products in this category contain 65% or more soluble solids. In low-calorie analogs, soluble solids range from 15% to 20%. Under these circumstances, commonly used pectins (high methoxyl content) do not suffice. Thus, special LM (low methoxyl) pectins must be used, along with additional gelling agents, such as locust bean gum, guar gum, and other gums and mucilagenous substances, some of which may require some masking. In the absence of sugar, a preservative, such as ascorbic acid, sorbic acid, sorbate salts, propionate salts, and benzoates, usually is required to the extent of about 0.1% (weight).

Soft Drinks. In addition to providing sweetness, sugar also functions to provide mouthfeel and to stabilize the carbon dioxide of soft drinks. To contribute to mouthfeel, the use of hydrocolloids and sorbitol has been attempted with limited success. Hydrocolloids also help to some degree with the problem of carbonation retention, but the principal solutions to this problem involve avoiding all factors which contribute to carbonation loss. Thus, the requirement for very well filtered water to eliminate particulates as possible nucleation points; any substances that promote foaming must be avoided; any emulsifying agents used in connection with flavoring agents must be handled carefully to avoid foaming; carbonation should be carried out at low temperature (34°F; 1.1°C); and trace quantities of metals must be absent from the water.

Bakery Products. These foods are among the most difficult as regards the use of artificial sweeteners. A listing of the functions of sugar in baked goods beyond that of providing sweetness is indicative of these problems. Sugar contributes to texture in forming structures, in providing moist and tender crumbs by counteracting the toughening characteristics of flour, milk, and egg solids. In the emulsification process required to retain gas during leavening, sugar is an effective accessory agent. Ingredients frequently used in bakery products to compensate for the absence of sugar include carboxymethylcellulose, mannitol, sorbitol, and dextrins, but, generally, these have not been very satisfactory—either to processor or consumer. This remains a large area of challenge for the food processors and ingredient manufacturers.

Evaluating Synthetic Sweeteners. Evaluation of new sweeteners, unlike that of most functional food ingredients, is not possible using totally objective means. There are no general rules leading to structure/function relationships for all classes of sweeteners. The principal judgments must rely on human sensory panel tests. The training and administration of sensory panels for sweeteners are beyond the scope of this volume.