How Sweet It Is
So, when it comes to exploring sweeteners in food and beverage formulations, a little sense about sugar is needed. Of course, there’s always room for this primary sweetener used in prepared foods and beverages. Whether listed simply as sugar—or as sucrose, refined sugar, cane/beet sugar, table sugar or white sugar—it remains the most common sweetener of foods in Western culture. Yet, sucrose (sugar) has been maligned for decades.
“An anti-sugar sentiment has arisen, along with obesity rates, with much finger-pointing,” says Sanford Wolgel, Ph.D., technology scout and business development consultant for the University of Chicago Office of Technology and Intellectual Property. “There is scientific substantiation for either pro- or anti-sugar stances, but the issue crossed over from science to politics and legislation—for example, New York City Mayor Blumberg’s ‘Ban the Supersize’ proposal. Some folks say [other] sweeteners, such as honey and agave, are ‘better.’ However, both of these sweeteners are quite similar in chemical profile to high-fructose corn syrup. For functional properties, no alternative high-intensity sweetener can match cane/beet sugar for providing bulk, humectancy and sweetness profile.”
Wolgel, who was director of R&D for Imperial Sugar from 2004–2008, also notes that brown sugar and molasses are good choices for some cooking and baking applications and have more nutrients than refined sugar. They do, however, add a richer flavor profile, with molasses especially strong, he adds.
Sweeteners like sugar perform multiple functions. Risen baked goods are in need of caloric sweeteners for bulk and to feed the yeast. Yeast-fermented white and whole-grain breads call for a touch of sweet for browning and flavor balance, too. These products can benefit from the addition of malt extracts rather than pure sucrose.
“Malt extracts function as a natural dough improver,” says Judie Giebel, a certified baker. “....[Sugars] in malt extract provide instant food for the yeast, [and] help to shorten fermentation and machinability, which keeps continuous baking operations on schedule. Malt softens the crumb, adds to volume and helps darken the crust. A natural humectant, malt extract will extend the shelflife of baked goods, reducing staling.”
Light malt extracts are a good option. Natural, pure malt extract made from caramel malt, when used at 1-3% in dough, will add a hint of malty caramel flavor and a tinge of warm color while providing all the functionality of standard malt extract.
“Caramel malt extract is beneficial in fresh and frozen pan, artisan and white breads, and pizza crust,” adds Giebel. “It’s label-friendly, because it is all-natural and is often on the label of any baked product made with flour that has been ‘standardized’ with malted barley flour.”
HFCS—Highly Fractious Controversial Sugar
The fact that the Feds kicked out the idea of re-badging high-fructose corn syrup (HFCS) as “corn sugar” shows how little the controversy over the sweetener has to do with actual science. From a molecular standpoint, the two are virtually identical: Both HFCS and sucrose are half fructose and half glucose (the percentage of fructose in HFCS can vary slightly on either side of the 50-50 divide, depending on manufacturing specifics). This is what is typical; however, HFCS manufacturers can make it any way desired, up to 90% fructose. The name came about several decades ago, in part as (ironically) a way to distance the sweetener from sugar. The “high-fructose” designation was in comparison to pure glucose syrup. Logically, if glucose-fructose disaccharides from beets and from cane can be called, respectively, “beet sugar” and “cane sugar,” then glucose-fructose disaccharides from corn should be allowed to be called “corn sugar.”
“There is no nutritional or scientific support to justify a reformulation from HFCS to sucrose,” states John White, Ph.D. White is the president of White Technical Research and a consultant to the food and beverage industry in nutritive sweeteners, including HFCS and sucrose. After working in food industry research and management for 13 years, developing a specialization in nutritive (caloric) sweeteners, he is one of the foremost experts on fructose and HFCS.
White’s conclusions are the result of 31 years of research on the production, functionality, applications, consumption and metabolism of the two sweeteners.
“HFCS and sucrose are nutritionally equivalent,” he adds, “so ‘No HFCS’ labels [could be considered a] warranty to consumers that the product has been nutritionally improved by reformulation. It has not. This misrepresentation opens the reformulator up to potential consumer backlash at some future date.”
Moreover, notes White, manufacturers that reformulate based on perceived demand are overestimating consumer interest, while manufacturers that reformulate hoping to reverse declining sales trends are “universally disappointed.” Sales trends apparently continue, unaffected by such reformulation. According to an April 2011 survey of more than 2,000 primary household grocery shoppers, conducted by Mintel Research Group Inc., only 4% of respondents claimed to be avoiding HFCS.
“There are significant added costs associated with reformulation,” continues White. “These include higher raw material—i.e., sucrose—costs; considerable capital expenditure, if dry sweetener handling equipment must be purchased and installed; increased labor and sanitation costs; changes in physical and functional properties for some products; and shorter shelflife for many products.”
A Granular Approach
Whether in syrup form or dry format, the variety of caloric sweeteners available to processors has expanded greatly. Among syrups, those from honey, molasses, maple, agave and sorghum, plus grain-derived syrups (other than corn syrup) from barley, rice, oats and others are the most commonly used in processing. Interestingly, all have a ratio of fructose-to-glucose on par with HFCS. Grain syrups generally have maltodextrins of various degrees of polymer (DP) as a side product of the conversion of starch to sugar, but the sweet sugars are glucose and maltose, not fructose.
Only very highly purified syrups can be isomerized in the manner of HFCS, which is a fixed-enzyme tower or column in which the syrup is passed through. (In fact, agave syrup—a highly popularized, “politically correct” replacement for HFCS—is typically higher in fructose than HFCS and can run as high as 90% fructose!)
The values of these non-granulated sweeteners in formulation, in addition to the obvious marketing one, are that many are offered in organic format and, to a degree, unrefined, with the trace-mineral content intact. Some contain small amounts of other functional carbohydrates. Honey, for example, can contain about 5-10% maltose, while agave contains inulin. Inulin, a short- to medium-chain polysaccharide also used to add bulk to sweeteners, is itself slightly sweet and can substitute for a portion of nutritive sweeteners in formulation. But, it also has health benefits; it’s known to help promote digestive health and regulate blood sugar, while increasing the body’s absorption of minerals such as calcium.
Most sweeteners, nutritive and non-nutritive, are commonly provided in dried, crystalline/granulated form, and the aforementioned syrup-based sweeteners also are available as granulated. Coconut sugar, for example, although enjoyed for centuries in the Far East, is new to the granulated sweetener scene in Western processing. It is a less-refined product made from coconut tree buds. Although it, and its botanical cousin, palm sugar, share a fructose content that ranges from about 35-50%, depending on the processing, it retains more of its non-caloric nutrients, including magnesium, potassium, zinc, iron, B vitamins and amino acids. Coconut sugar is said to contain 36 times the iron, four times the magnesium and over 10 times the amount of zinc as brown sugar, the ingredient to which it is usually compared.
In addition, most coconut sugar available to manufacturers is organic, non-GMO, gluten-free, kosher and sustainably produced. Compared to sugar cane, coconut palms produce 50-75% more sugar per acre, yet use less than a quarter of the resources. Coconut sugar has a mild sweetness and can be readily substituted for granulated and light brown sugars in recipes. Applications can include hot and cold beverages; bakery and dessert products; glazes; and even yogurt and smoothies.
Crystalline fructose, another common sweetener, has experienced less controversy than HFCS. At about 170% the sweetness of sucrose, it has the same calorie load and can be used interchangeably with sucrose in most formulations.
Meeting Sweet Halfway
Sweetener science and technology has approached the zero-/low-cal sweetener challenge from two basic starting points, focusing on either “nutritive sweeteners” (those which have absorbable carbohydrates that provide calories) or “non-nutritive” sweeteners (those in which the carbohydrate portion of the molecule is bound to a chemical fraction that blocks the metabolism of the carbohydrate). Some sweeteners fall in between, carrying only a partial caloric value compared to carbohydrates.
According to the International Sweeteners Assn., there has been “significant growth in the global use of all low-calorie sweeteners.” The association puts that growth at 40% in just the past five years, noting that it “reflects a year-on-year increase in the number of new products containing low-calorie sweeteners, which have been launched to markets around the world.” This figure includes both lower-calorie ingredients, such as short- to medium-chain polysaccharides to sugar alcohols, as well as the growing list of natural and artificial zero-calorie sweeteners.
Sugar alcohols—sometimes generically referred to as polyols—include sorbitol, mannitol, maltitol, erythritol, xylitol, isomalt and lactitol. They provide only about 1.5 to 3 kcals per gram so are often used to lower, rather than replace, the 4 kcals per gram provided by glucose, fructose, sucrose and the other fully nutritive sweeteners. But, they also are only about half as sweet as sucrose. Advantages include non-cariogenicity (non-cavity forming) and, most importantly, their use as a bulking agent when combined in sweetener systems with zero-calorie sweeteners. They also have a stability and water activity that can enhance textures, especially in baked products and dairy formulations.
Disadvantages to sugar alcohols are varied, ranging from taste considerations to adverse physical issues. Some have a “cooling” effect that enhances “mintiness” (an advantage to chewing gum and candy manufacturers, which is where most applications of these sweeteners are seen); some have a medicinal or metallic taste. The common physical drawbacks are usually secondary to overconsumption, and those include gastrointestinal distress and bloating, as well as a laxative effect.
While the gulf between developing zero-/low-cal sweeteners and the perfect sucrose mimic has narrowed significantly in the past few years, precise replication of sucrose in flavor and function has yet to be achieved. In the interim, something interesting has happened: The gap has shrunk of its own accord, in that consumers’ palates have become more adaptive. An entire generation has been raised with a variety of flavor profiles for satisfying a craving for sweet. While the non-nutritive sweeteners aspartame, sucralose, neotame, acesulfame-K (acesulfame potassium), saccharin and cyclamates can be said to have bridged this gap, some preference tests have shown that consumers are so used to their taste profiles they prefer them over sugar-sweetened products.
That adaptation, coupled with the tidal wave of consumer demand for non-artificially sweetened products, created a perfect storm for two botanical sweeteners that have enjoyed a prodigious surge in usage in just a few short years, stevia (Stevia rebaudiana) and luo han guo. The first is from a leaf native to the Amazon but now also grown in Asia, and the second, a fruit of Asian origin. Stevia is about 200-350 times as sweet as sucrose, while luo han guo is about 150-250 times as sweet..
Both ingredients are heat-stable, pH-stable, shelf-stable, non-GMO and available from some suppliers as natural extracts made without the use of chemical solvents. With the big jump in demand and a rush to supply—coupled with a jump in the price of sugar—they are cost-competitive compared to sucrose, when the amount of “bang for the buck” is taken into account. In fact, in some applications, it can cost less to use these ingredients than to use sugar.
Stevia leaves get their sweetness from glycosides, glucose molecules bonded to a non-sugar molecule. The main steviol glycosides are stevioside and rebaudioside-A. These two molecules are 100-300 and 250-450 times sweeter than sucrose, respectively. Stevia extract is derived from the leaves after drying.
Previous issues with stevia, specifically bitter and licorice flavor notes, had to do with cruder methods of extraction. Not only have the methods of extraction and purification improved markedly, technology has advanced to allow some manufacturers to extract the glycosides without use of solvents. The purity issue, too, has seen some changes. In order to chase away the bitter or licorice notes, early development focused on getting stevia into as pure a form as possible.
Both of these glycosides have proven highly stable in multiple processing conditions, with long shelflife and minimal loss (less than 1%) under heat pasteurization or in the presence of low pH. The disadvantages are a very long flavor with slow onset; a distinct flavor when used as the sole sweetener; and, of course, a lack of bulking capacity when used in baked formulations.
However, the latest breakthrough for stevia has been a refocus on the characteristics of the individual glycoside components. The stevia plant contains more than 30 glycosidic compounds, and forward-thinking ingredient makers are looking at the distinct characteristics of each one and how they work in combination. Most stevia offered comes in 97-99% pure forms. However, it was recently determined that 95% pure stevia has distinct characteristics that present advantages in some recipes. This has been accompanied by the combination of the various glycosides into systems that play on the strengths of each one.
On a side note, sustainability and reduction of carbon footprint have been playing a strong role of late for at least one stevia producer, allowing for a more consumer-friendly sweetener in more ways than flavor profile. Also, another stevia maker has patented a more efficient method for extracting rebaudioside-A. The process is 33-50% faster than conventional methods, resulting in a much more efficient and cost-effective production. The extraction procedure can draw rebaudioside out of mid-grade extracts to make a 95% grade or higher powder. Moreover, the method is all-natural, relying on water and food-grade ethanol—the same as that used in drinkable spirits—for the extraction, as opposed to methanol or other extractive solvents.
Luo han guo, which was overshadowed by stevia, has seen sudden interest by re-badging itself by its nickname, “monk fruit,” a type of gourd related to melons and cucumbers. The Southeast Asian fruit had been used for centuries as a sweetener that also was used to help manage diabetes and was applied in Chinese medicine for other ailments, including colds and lung disorders. Monk fruit also gets its zero-calorie sweetness from glycosidal compounds, in this case, mogrosides. The sweeteners from this fruit are available in crystalline form extracted from the concentrated juice and are typically offered in graduated percentages as blends with other sweeteners. It is stable, water-soluble (as with stevia) and considered allergen-free.
The Art of the Blend
With high-intensity sweeteners, such as stevia and monk fruit, it is common to offer them as blends in order to both mask the intensity and to provide the bulk needed to incorporate the sweetener into bakery and other such formulations. Typically, they are paired with maltodextrins, inulin, erythritol or other sugar alcohols.
Dried syrups, such as honey, malt and molasses, are products that have been converted into a free-flowing granulated ingredient also able to substitute for some or even all of the sucrose in a formulation. They provide ease of use and can be of significant advantage in a spectrum of applications, including baked goods and cereals, nuts and snack foods, beverages, meat products, and dressings and sauces. They’re more readily scaled, and can be handled and stored across a wider range of temperatures. Since many syrups require warming or heating prior to inclusion, the risk of overheating exists. This can lead to color and flavor changes.
Dried syrup sweeteners can be added with the other dry ingredients without rehydration (in dough and batter applications, the addition of 1 cup to 1 pint of water for every pound of dry sweetener might be necessary, but the yield will also increase.) Cost savings come not only from the easier storage and use, but from the reduction of waste, via spillage and spoilage (sanitation can be a big issue with wet sweeteners), which, for syrups, can run to 10% or greater. This ease of storage and handling also means dried syrups can remove the need for special equipment. Labeling changes are rarely needed when substituting dried syrups for wet.
Demands of today’s sophisticated consumers put development of natural and naturally processed sweeteners on a fast track that led to cleaner labels and more subtle experiences. The result is that processors are now better able to fulfill the core craving and satisfaction of the 21st century sweet-tooth. While the grail quest for a perfect, calorie-free clone of sucrose’s flavor and function profile might continue, the recent achievements in sweetener technology have brought an array of nonpareil sweetener options to the table.
Working with Grain-based Sweeteners
Nutritive sweeteners are comprised of about 47% sucrose derived from cane or beets, 38% corn-derived syrups, and 15% comprised of a combination of rice syrup, tapioca syrup, agave and similar sources. Corn-derived syrups are the dominant grain-based sweetener. With the recent public outcry [blaming] high-fructose corn syrup for diabetes in children via obesity, this nutritive sweetener is taking a public beating as a healthy sweetener. The fructose is being blamed, as well as two other factors of this grain-sourced sugar.
First, since approximately 95% of corn grown in the U.S. is from a genetically modified variant, plus it typically utilizes cultivation practices involving herbicides and pesticides to achieve fantastic yields, some consumers are put off. Second, the enzymes used in corn syrup processing are genetically modified, though extremely desirable from the standpoint of activity and cost. In particular is the isomerization enzyme, which converts glucose to fructose so that corn syrup can achieve a ratio of glucose to fructose similar to invert sugar from sucrose, while matching sweetness levels desired in product formulation.
The controversy lies in the fructose as being different and assumes that as causative of obesity/diabetes. Yet, research has not uncovered a difference between fructose from corn syrup, fructose from sucrose or fructose from fruits. The very few studies flagging a dietary “link” to the public’s health concerns are not in consensus with [mainstream] scientists. Established scientific facts require duplication of results and examination of methods before something becomes a “fact.” These studies are preliminary. But, consumers are seeking less processing, more purity (interpreted as being more “natural”) and demanding that the product retains its natural nutritive value.
Corn syrup is the least expensive nutritive sweetener available—about one half the cost of sucrose and about a third the cost of the next most available grain-derived sweetener, rice syrup. Other issues to consider are the differences food formulators encounter in replacing HFCS or sugar. Food scientists consider different functionalities, such as sweetness level and amounts used, viscosity, adherence of particulates, product texture and flavor profile.
Another consideration is the difference in taste or perceived sweetness and its profile. The sweetness profile for sucrose has a classic desirability; it is well-perceived initially and lingers long enough to satisfy. The lower level of sweetness from glucose (or glucose-maltose) syrups lacks the longer sweetness perception—it’s more of an early “hit” followed by a rapid dissipation. Options to lengthening the sweetness profile can come from taking advantage of viscosity as affected by other components, such as maltodextrins, oils and gums. Syrups tend to be just sugars, very highly purified for the purpose and used to reduce off-flavors or particulates.
HFCS has the sweetness profile that reflects sugar closely. It is not the only sweetener successfully employed in foods and beverages. A grain-derived sweetener made from oats has recently been introduced at a price comparable to rice syrup.
Sweeteners that add extra functionality and nutrition currently are highly desirable. There are some inherent problems with corn syrup or HFCS, sugar and rice syrup in cereal bars. In, for example, chewy bar formulations, there is the need for a stabilizer, such as a sugar alcohol, to retain this texture on the shelf and not harden or crystallize. Multicomposition syrups, such as oat syrup, appear to avoid this quite well, retaining texture.
The behavior (rheology, water binding, etc.) that comes into play for enrobing applications, such as sugar-coated RTE cereals and clusters, demands a lot from syrup sweeteners. Formulas usually need to be adjusted based on the sugar characteristics for a glaze vs. a frost. To form a frost, the addition of an opacity ingredient (typically gelatin) is needed, because HFCS and glucose or glucose-maltose syrups will not form the desired crystals.
For a glaze, the preferred syrups have been invert, HFCS or glucose-maltose syrups (such as rice or oat, at various DEs). While pure glucose or HFCS glaze beautifully, they are hygroscopic and cause RTE products to “brick up” in the package. Glucose, with added sucrose and a 42 DE syrup, is used to reduce the moisture absorption. The monosaccharide, plus maltodextrin and a small amount of oil, impede sucrose mobility, which in turn prevents crystallization or frost. Thus, syrups with oil, dextrins and fiber can aid final glaze. These qualities are already inherent to oat syrup.
Paul Whalen, Ph.D., holds a doctorate in Food Science & Technology from the Univ. of Nebraska-Lincoln. He also has an M.S. in Microbiology.
Sweet As Licorice
In the early stages of development, stevia was hampered by what some consumers considered a “bitter, licorice-like flavor note.” Although ingredient makers have met the challenge of losing or masking that quality, a new masker for such sweeteners has been developed from—wait for it—the active flavor compound in licorice, glycyrrhizic acid. Monoammonium glycyrrhizinate works in tandem with other sweeteners to magnify them; mask off-notes; lengthen the sweetness profile and duration; and, since it has a hydrocolloidal capacity, contribute to a silky texture.