The many positives of polyols
August 9, 2011
by Jeff Gelski
Consider them the workhorses of sugar-reduction strategies. Polyols, also known as sugar alcohols, may not offer such claims as “300 times as sweet as sugar” like some high-intensity sweeteners, but they play vital roles. How would reduced-sugar cakes, muffins and cookies succeed in the market without the help of polyols?
Polyols may replace the bulk of sugar, at less of a calorie count, in grain-based foods. They may work in tandem with high-intensity sweeteners, and some polyols offer shelf life benefits because of their humectant properties.
The American Diabetes Association, Alexandria, Va., recognizes erythritol, hydrogenated starch hydrolysates, isomalt, lactitol, maltitol, mannitol, sorbitol and xylitol as sugar alcohols/polyols. The association also recognizes the need for polyols and other low-calorie sweeteners.
“Foods with low- or reduced-calorie sweeteners can have fewer calories than foods made with sugar and other caloric sweeteners,” the association said. “That can be helpful if you’re trying to lose weight or even to prevent weight gain. These products often times also have less carbohydrates, which can be helpful in managing blood glucose levels.”
More than 186 million American adults, or about 80%, are “weight conscious,” according to a survey released in April by the Atlanta-based Calorie Control Council, an international non-profit association representing the low-calorie food and beverage industry.
The survey also found 54% of American adults want to reduce their weight. Among weight loss methods, 86% mentioned cutting back on foods high in sugar. Other tactics included eating smaller portion sizes (85%) and consuming low-calorie and sugar-free foods and beverages (78%).
The Children’s Food and Beverage Advertising Initiative criteria released in July mentioned sugar reduction. Food and beverage companies will follow uniform nutrition criteria for foods advertised to children under the criteria of the initiative, a program of the Council of Better Business Bureaus. Among grains, fruit and vegetable products, food with 150 calories or less must contain no more than 1.5 grams of saturated fat, 290 mg of sodium and 10 grams of sugar.
To achieve sugar reduction and maintain product quality, grain-based foods companies should choose a specific polyol based on application.
“Look at polyols in the same way you would look at the wide range of sugars and syrups — depending on their structures and properties, they have different functionalities in applications,” said Ronald C. Deis, Ph.D., director, applications, Sweeteners & Polyols, Corn Products International, West Chester, Ill. “For example, crystalline maltitol is an excellent replacement for sucrose in something like a cupcake due to its structural similarity (in terms of molecular weight) to sucrose. Its effect on the gelatinization temperature of the starch in the flour is very similar to that of sucrose, and it has similar crystalline properties. Granola bars depend on sugars for binding properties as well as sweetness, and for this reason maltitol syrups work well for this application.
“This just highlights two of the polyols, but you need to remember that their properties as a group are diverse, with specific benefits. You do need to consider the serving size of the product, especially in baked goods, using no more than 10 to 15 grams a serving.”
If sweetness is the only consideration for a product, xylitol would be the preferred polyol because its sweetness is identical to sucrose, said Carl Jaundoo, senior applications specialist for Roquette America Inc., Keokuk, Iowa.
“However, maltitol, with a relative sweetness of about 90% compared to sucrose, is more widely used in grain-based foods as its combined functionality (sweetness, solubility, cooling effect) is almost identical to sucrose,” he said.
Roquette offers Lycasin 75/75 maltitol syrup. To be labeled maltitol syrup, a product must contain at least 50% maltitol, Mr. Jaundoo said. In the case of Lycasin 75/75, the prefix 75 represents the solids while the suffix 75 represents the maltitol content. Benefits of Lycasin are bulk characteristics, sweetness contribution and ability to enhance texture, he said. It behaves like traditional corn syrups and adds viscosity and chewiness. Lycasin contributes to the chewiness of cookies and retains moistness in muffins and brownies.
Roquette also offers SweetPearl maltitol. A study showed its glycemic index at 29, low when compared to sucrose at 100.
Danisco, which has a U.S. office in New Century, Kas., offers Dulcaden MS maltitol syrup for nutrition bars and baked foods. It enables companies to claim sugar-free, no added sugar, reduced calorie and reduced glycemic load. Processing and formulation advantages include high thermal stability, high chemical stability and high micro-stability.
While polyols may replace the bulk of sugar in reduced-sugar grain-based foods, high-intensity sweeteners may be needed to fully replace the lost sweetness.
“Polyols work well with high-potency sweeteners to balance the overall sweetness profile,” Dr. Dies said. “High-potency sweeteners deliver a higher intensity either early or late over time and/or can have lingering sweetness. Due to a more balanced profile, polyols can help to balance the mixture profile. Maltitol and maltitol syrups interact well with high-potency sweeteners such as aspartame and sucralose.
“Since stevia extracts are natural sweeteners, choices are limited in the polyol group. The only natural polyol is erythritol, and this works well to balance the profile.”
Corn Products International offers Enliten stevia extracts, which are high-intensity sweeteners.
“Bulking agents that may be used with Enliten are Maltisweet CM40 crystalline maltitol, which is a polyol most similar to sucrose, Erysta crystalline erythritol C40 for its high tolerance level, or a combination of both depending on the desired results,” said Eric Shinsato, specialist staff technical service-sweetener solutions, Corn Products International.
The Truvia brand tabletop sweetener includes stevia extracts and erythritol.
Jungbunzlauer, based in Basel, Switzerland, offers Erylite stevia, which is a blend of Erylite (the company’s brand of erythritol) as the bulking agent and stevia plant extract as the high-intensity sweetener. It works as a 1:1 sugar replacement in foods and beverages.
Other sugar-reduction applications
Chocolate, icings and fruit fillings all are used in grain-based foods applications, and all offer possibilities for sugar reduction in the final product.
Dr. Dies said the choice of polyol in applications such as fruit fillings, icings, caramels and chocolate depends on whether crystallinity is needed.
“You need crystallinity in chocolate, but it would be a defect in a fruit filling,” he said. “Other factors to consider are level of sweetness and viscosity. For chocolate, crystalline maltitol is recommended and often used in chocolates. For fruit fillings and caramels, maltitol syrups are usually chosen due to the level of sweetness and range of viscosity available. Icings or fillings can use maltitol syrups, and a crystalline polyol such as crystalline maltitol can be added to encourage some crystallization in an icing.”
Xylitol may be used in sweet baked goods along with frostings and fillings as a 1-to-1 sugar replacement, according to Danisco. Xylitol masks bitter notes from high-intensity sweeteners and vitamins, and it has 40% fewer calories than sugar.
Hygroscopicity is a critical consideration in sugar-free chocolate, Mr. Juandoo said. Maltitol or erythritol, both polyols with low hygroscopicity, may replace sugar. He added that in fruit fillings, maltitol syrups with varying amounts of sorbitol may contribute humectancy.
“In grain-based foods, moistness is a desired characteristic,” he said. “For this application, polyols can contribute moistness or humectancy. Among the most commonly used polyols, sorbitol has the highest hygroscopicity followed by xylitol and isomalt.
“In many instances, a combination of polyols can be used to achieve the desired finished product attributes. For example, maltitol can be combined with sorbitol to replace sucrose to create a cookie which will have a soft texture during its shelf life.”
A closer look at polyols
The Atlanta-based Calorie Control Council, an international non-profit association representing the low-calorie food and beverage industry, gives advice on the benefits of specific polyols, also known as sugar alcohols. Each polyol has fewer calories per gram than sucrose, which has 4 calories per gram.
Erythritol — About 70% as sweet as sucrose, erythritol has a caloric value of zero per gram while its high digestive tolerance distinguishes it from other polyols. Erythritol occurs naturally in fruit such as pears, melons and grapes as well as food such as mushrooms, wine, soy sauce and cheese.
Isomalt — It is used often in products that are boiled, baked or subjected to higher temperatures because it may be heated without losing its sweetness or being broken down. When used alone, isomalt contributes 45% to 65% of the sweetness that would result from the same amount of sucrose, and it often is used in combination with high-intensity sweeteners. Isomalt is made from sucrose and looks a lot like table sugar. It is 2 calories per gram.
Lactitol — Because of its stability, solubility and similar taste to sucrose, lactitol may be used in a variety of low-calorie, low-fat and/or sugar-free foods such as ice cream, chocolate, hard and soft candies, and baked foods. Lactitol is 40% as sweet as sucrose and 2 calories per gram. It may partner with other low-calorie sweeteners such as acesulfame potassium, aspartame, neotame, saccharin and sucralose.
Maltitol — It is about 90% as sweet as sugar and 2.1 calories per gram. The high sweetness allows it to be used without other sweeteners.
Mannitol — It is non-hygroscopic, meaning it does not pick up moisture. Due to a high melting point of 165 to 169 degrees Celsius (329 to 336 degrees Fahrenheit), mannitol is used in chocolate-flavored coating agents for ice cream and confections. It is 50% as sweet as sucrose and about 1.6 calories per gram.
Sorbitol — It is used as a humectant in many products for protection against loss of moisture content. It is 60% as sweet as sucrose and about 2.6 calories per gram. Cookies, cakes, icings and fillings are examples where sorbitol may be used in grain-based foods.
Xylitol — It may play a role in reducing development of tooth cavities. The white crystalline powder is about 2.4 calories per gram. Xylitol occurs naturally in many fruits and vegetables.