Sweeteners: Beyond Sweetness
August 01, 2009
by Rebeca López-García
The use of natural sweeteners has certainly evolved during the past few decades, and the road has not always been sweet. From using refined sugar to the high-fructose corn syrup (HFCS) controversy to the new functionality of polyols, the use of these label-friendly ingredients has certainly become more interesting.
BEYOND THE DEBATE.
Sweeteners have long been the center of a health debate that is fueled by the overwhelming concern regarding the obesity epidemic. Thus, recently, many companies have considered reformulating products to avoid using HFCS and create products that may seem healthier to consumers. However, scientific evidence suggests that all caloric sweeteners are equal as far as energy is concerned; they all contain 4 Cal per g. Once broken down, the human body cannot determine the source of energy.
A supplement published in the June 2009 issue of the Journal of Nutrition encouraged the scientific community and the public to rethink the myths about HFCS impact on the American diet. “State of the Science on Dietary Sweeteners Containing Fructose” is the scientific summary of a joint conference held in March 2008 that brought together several scientific leaders from various backgrounds who found there is little evidence that HFCS and sugar (or sucrose) have differing effects on satiety, overall energy balance, metabolic hormones or biochemical metabolites such as triglycerides and uric acid.
Joseph Hickenbottom, vice-president, sales and marketing, Malt Products Corp., Saddle Brook, NJ, concurred that it is certainly not worth reformulating for a media misinformation attack against HFCS based on misleading tests. All those tests have been refuted many times, he said.
So it is important to consider this information before reformulating products based solely on this consumer debate. Reformulation should only be considered in an overall consideration of health and taking advantage of the benefits of different ingredients such as fibers, whole grains, fruits, nuts, etc. rather than just removing ingredients that are at the center of a debate.
FORMULATION AND FUNCTIONALITY.
To consider formulation with different sweeteners, it is important to fully understand their functional roles and the chemistry of the different products available in the market. Baked foods such as cakes, cookies, quick breads and yeast breads require sugar for flavor, pleasing color, tender texture, improved shelf life and yeast fermentation.
With these properties in mind, it is possible to explore substitutions for better sweeteners, more label-friendly or lower-cost products. According to Ronald C. Deis, PhD, vice-president, applications research and technical services, Corn Products US, Westchester, IL, several key questions should be addressed by a formulator when changing sweeteners in a bakery formulation:
• Are the sweeteners equi-sweet, or do I need to compensate for sweeteners with a high-intensity sweetener or a flavor?
• Does the new sweetener occupy the same space (bulk) within the formulation (for example, replacing sucrose with a high intensity sweetener)? Does the new sweetener change the level of solids within the formulation, and do I need to compensate with a bulking agent?
• Is the new sweetener or sweetener system different in molecular weight or molecular weight distribution than the sweetener I am replacing? This, or other characteristics of the replacement, may alter starch gelatinization temperatures and the temperature at which proteins denature — factors that are critical to the texture and flavor of the final product.
• Have I correctly balanced the moisture in my formulation?
HFCS AND SUGAR SYRUPS.
Syrups are commonly used to build viscosity and maintain moisture and softness. They also have been a good alternative because, once the infrastructure is installed, handling is easier than use of bulk sugar.
HFCS was originally used as a substitute for sugar in many formulations because of cost and handling issues. Although the ongoing consumer-driven debate may scare some companies off using HFCS, according to Ric Boyd, technical sales support manager, Corn Products US, more and more consumers are beginning to understand the facts surrounding HFCS, and HFCS has a number of benefits. It provides a cleaner taste and offers faster and more predictable fermentation with better microbiological stability than sucrose.
Sucrose syrup is commonly used to replace HFCS. However, sucrose syrups are lower in solids and more susceptible to microbiological instability than HFCS, Mr. Boyd said. The sucrose must be monitored closely to make sure no spurious fermentation or off-flavors develop in the storage tank. Another microbiological and technological challenge is that liquid sugar requires storage at 68°F or higher. Typically, sucrose syrups have sodium hydroxide added to them to raise the pH above 8.2. This helps retard the microbiological activity. HFCS does not have this problem because solids are high enough to keep the product more stable.
During leavening, yeast produces acids and enzymes to invert sucrose yielding the monosaccharides dextrose and fructose. Some off-flavors are associated with the yeast inverting the sugar. In HFCS only the simple sugars are present, therefore, this step is unnecessary, and the off flavors are not an issue, Mr. Boyd concluded.
Mr. Hickenbottom also recommended against substitution with sucrose syrup because “it has a 30-day shelf life, is more expensive than HFCS and offers no advantages. If dry sucrose is being considered, then price, formula changes for the moisture difference and bake times should be considered. Medium invert sugar would be a better choice than sucrose syrup, but again, HFCS beats it hands down.” More information on HFCS can be found at www.sweetsurprise.com .
If health is a consideration, then one option is sucromalt. This is a full-calorie natural sweetener syrup made from sucrose and maltose that has already been confirmed as generally recognized as safe (GRAS) by the Food and Drug Administration. Cargill, Minneapolis, MN, is the only company that produces sucromalt and markets it under the Xtend brand. This syrup is a low-glycemic alternative to sugar and HFCS for consumers who desire to manage their energy and blood glucose levels. Because sucromalt is a syrup, it appeals to manufacturers familiar with HFCS or other syrups such as corn syrup. This product is ideal for formulation of energy bars.
A combination of isomaltulose, a sweetener that occurs naturally in both sugar cane and honey and can be produced by enzymatic conversion of sucrose, and sucromalt may also be used to formulate products with lower glycemic index (GI). Isomaltulose has a bland taste, with a sweetness level half that of sucrose. It has good heat and acid stability and low hygroscopicity. Both sucromalt and isomaltulose are reducing sugars and, therefore, take part in Maillard browning reactions.
Other commonly used natural sweeteners available to bakers include maple syrup, juice concentrates, sorghum, rice, tapioca and agave syrups, honey, and molasses. These may be used to create friendlier labels while taking advantage of their unique flavors and good consumer perception.
According to Mr. Hickenbottom, each one has its own merits, replacement levels and bake times. All, however, are more expensive than HFCS.
Polyols are carbohydrates derived from sugars but not metabolized in the same manner as sugar. Polyols have fewer calories than sugar but are used in the same amounts in a formula. In general, polyols have no off-flavors, are stable at high temperatures and work best in applications such as cakes or cookies where bulk is needed to maintain the finished product integrity.
To choose a polyol, it is important to understand the carbohydrate that will be replaced because the molecules usually have the same functionality and molecular weight as the products from wich they are originally derived (corn syrups and sugars). For example, to substitute for a 63-DE corn syrup, a maltitol or polyglycitol syrup (also known as hydrogenated starch hydrolysate) would work well.
According to Dr. Deis, the advantage of maltitol and maltitol syrups is that, on a molecular weight basis, they can directly replace nutritive sweeteners without many formulation changes. On the other hand if sucrose is to be replaced, then compounds with similar molecular weights• such as lactitol, isomalt and maltitol would be good choices. Monosacharides could be replaced with erythritol, mannitol, sorbitol and xylitol.
In addition, it is important to consider the solubility, melt point, cooling effects and digestive tolerances of each polyol. For example, according to information from Roquette, Inc., Keokuk, IA, maltitol has similar characteristics to sucrose. So, it allows weight-for-weight substitution. It also has equivalent crystallization, which results in similar crunchiness for cookies. And because viscosity and solubility are also similar, formulations involve the same dough processing, and products have similar volume and texture.
Erythritol is a good choice because it is more digestively tolerant than sorbitol and maltitol and has 0 Cal. In different formulations, erythritol or a combination of erythritol and maltitol can replace most if not all of the sugar.
When using these polyols, the baking process may need to be modified slightly. Doughs formulated with erythritol require slightly lower baking temperatures because cakes tend to become darker. The lower temperature may be compensated with a longer baking time. Products with erythritol tend to have softer crumb and harder crusts, so formulations may have to be adjusted to replace only a portion of the sugar. Also, after prolonged storage, the cooling effect of erythritol may be sensed, and crumbs may harden caused by re-crystallization. This may also be counteracted with a combination of other sweeteners. In addition, erythritol is less sweet than sugar, and this can be compensated with the addition of a high-intensity sweetener.
TREHALOSE TRAITS. Trehalose is a naturally occurring sugar with similar functionality to sucrose but with greater stability and less sweetness. It can be used to improve existing products because it is a multifunctional sugar. Trehalose is fully caloric, has no laxative effects and is broken down in the body to glucose. It has a moderate GI with low insulemic response. According to information from Hayashibara , Inc., Broomfield, CO, trehalose has many potential uses in bakery products. It moderates sweetness in cakes and biscuits, icings, bakery cremes and fruit pie filling allowing the full flavor potential of the product to be appreciated without compromising product shelf life. It also facilitates fat reduction in sweet biscuits, bakery cremes and frostings. It can improve consumer acceptability by optimizing sweetness in highly-caloric indulgent products containing high levels of fat and sugar. Trehalose reduces moisture migration in multicomponent bakery products thus extending shelf life.
With its recent approval in many markets, stevia (also commonly known as Reb-A, rebiana or stevia glycosides) is the new kid on the block. Stevia is a natural high-intensity sweetener that is 200 to 300 times sweeter than sucrose and contributes 0 Cal. It is naturally extracted from the plant Stevia rebaudiana. According to Dr. Deis, because stevia is a high-intensity sweetener, the bulk of any sugar removed must be replaced by another ingredient. This ingredient may be a polyol, a maltodextrin or polydextrose.
The natural status in combination with its calorie-free sweetness puts stevia in a great position to develop products. However, this will not come without a challenge. According to information recently published by Markus Eckert, Ph.D., Kerry Ingredients, Beloit, WI, Reb-A stevia is quite different from sugar. Dr. Eckert stated: “It takes longer for the sweetness to peak; it has a different mouthfeel and a distinct aftertaste that is perceived as being bitter and licorice-like.” Thus, companies such as Kerry Ingredients have been working on different products that work in conjunction with Reb-A stevia to give it the fast onset and mouthfeel of sugar with little to no aftertaste.
Cargill also has worked on developing flavor solutions and has taken a dual-layered approach starting with technology to examine taste responses to Reb-A at the cellular level and then developing flavor solutions based on the findings. Similarly, flavor companies such as Givaudan, Symrise, Comax and Firmenich have developed ranges of bitter blockers that help develop products with stevia and capitalize on its potential as a natural sweetener. Stevia-based sweeteners will continue to develop as formulators become comfortable with its characteristics.
In general, as consumers understand the facts about HFCS, suppliers will continue to use it because it offers many advantages as a natural sweetener with good functionality and unbeatable cost. However, the range of natural sweeteners available offers excellent advantages that formulators can explore to obtain different functionalities, reduce calories, lower GI, extend shelf life or simply obtain better products that appeal to different consumers. Naturally, future trends in this area offer a sweet range of possibilities.