Polyols for Calorie and Sugar Reduction

Ronald C. Deis, Ph.D., Contributing Editor

The drive to curb the obesity epidemic seems to have moderated approaches to sugar and fat reduction in product development. Especially in categories where serving sizes can be large, replacement of all of the sugar and/or fat often leads to products that are not appealing to the consumer.

A much more moderate approachthe reduction of calories through partial fat replacement and a 30% to 50% reduction in sugarhas led to more consumer-acceptable products, which, like 100-calorie packs, have a better chance of acceptance for weight management.

Polyols: novel sugar replacements

Polyols are a group of sugar-replacement ingredients with a great deal of utility in this trend. They have become widely accepted, especially in confectionery, where serving sizes are smaller and sugar-free has become the norm. Consumers expect their chewing gums and breath-fresheners to be sugar-free, and parents encourage their children to chew these products due their cariogenic or cariostatic benefits. Polyols have functional benefits in these products, as well. They are excellent plasticizers, keeping the gum soft and pliable over time, and they also work well with high-potency sweeteners in establishing the sweetness and flavor profiles that are now expected in chewing gums. In hard-boiled candies, they are the majority of the candy piece, establishing the structure and maintaining that structure through the shelf-life of the candy, but also providing, in combination with other sweeteners, the sweetness and flavor profile. In other confections, such as jellies, gummies, taffies, fondants and caramels, some polyols are integral in establishing the crystalline or semi-crystalline structure that defines a particular confection, while other polyols serve to control the rate of crystallinity for shelf-life purposes.

Polyols serve these same purposes and more in nutritional bars, baked goods, ice creams and other products in many ways. First of all, confectionery products are often a defining part of products within these categories, serving as inclusions, variegates, toppings, icings, etc. Secondly, the same properties as described for confectioneries also apply to baked goods, dairy products, nutritional bars and other categories. Polyols are products created by the hydrogenation of sugars (Figure 1), and they affect polymeric structures in much the same way as their originating nutritional sugars, and often bring more beneficial properties into play, as well.

Defining polyols

Polyols can be divided into three groups: monomers, dimers and polymeric mixtures. The monomersconsisting of one carbohydrate unitare erythritol, mannitol, sorbitol and xylitol. The dimersconsisting of two bonded carbohydrate unitsare isomalt, lactitol and maltitol. And the polymeric mixtures are combinations of polyolsvarying in lengths of repeating carbohydrate unitsthat are identified as polyglycitol syrups, also known as hydrogenated starch hydrolysates (HSHs), and maltitol syrups (most similar to corn syrups). Nomenclature is determined by the amount of maltitol (dry basis) present; a syrup that contains greater than 50% maltitol is considered a maltitol syrup, and anything less is a polyglycitol syrup. 

Polyols are not considered sugars because they are not completely digested or absorbed. The majority of the polyol reaches the large intestine, where bacteria metabolize what has not been absorbed or excreted previously to short-chain fatty acids. The effect of this is similar to experiences one might have with high-fiber foods, and the effect is variable, depending on what else has been consumed, as well as individual sensitivity. The result may be a feeling of fullness, laxation or gas, and the results are temporary. How do you avoid this? First, by using polyols as a formulating tool to reduce sugar and calories, not to replace sugars entirely, and second, knowing which polyol to use to minimize any tolerance issues. Calories and sugar can be reduced substantially in many formulations while using polyols at no more than about 10 grams per serving. By contrast, some of the products on the market 10 years ago contained more than 20 grams per serving, which probably affected sensitive individuals for one serving, but affected many more who might eat two servings in one meal. Polyols can reduce caloric density in a formulation because often they are half the calories of sugar (Table 1).

The portfolio of polyols available offers a wide range of properties, which allows convenient replacement of sucrose and sweeteners in many formulations. These polyols vary in caloric density, tolerance (as briefly discussed), solubility, molecular weight, cooling effects as crystalline forms are solubilized, and regulatory status. Each of the polyols has unique properties that enhance performance in some applications or require formulation changes in others. In many applications, the molecular weight (MW) of sugar replacers (Table 2) plays a large part in the performance of a product, because the MW influences starch gelatinization temperature, boiling points in fillings and protein denaturation in baked products. In ice creams, the MW of the carbohydrate portion has a major effect on the freezing rate of the mix, as well as the freezing point of the final product.

For no-sugar-added ice creams, the sugar-replacement portion is often a mixture of sorbitol, polydextrose, maltodextrin and high-potency sweetener, the sum of which mimics the freezing rate of sucrose in the mix, as well as the freeze point of sugar in the final product. Since sorbitol has half the MW of sucrose, it depresses the freeze point much more than sucrose does, so higher MW polymers must be added to compensate for this. Maltitol syrups are, like corn syrups, liquid blends with a polymeric distribution that can be modified to fit a need, or easily blended with other polymers, such as soluble fibers or high-potency sweeteners, to increase manufacturing efficiency. In the case of the no-sugar-added ice creams, a maltitol syrup with the correct blend or polymers can easily replace all of the ingredients mentioned above. In baked goods, the MW distribution (and solubility) of the carbohydrate portion will raise or lower the starch gelatinization temperature, which will have an impact on cake volume or cookie spread and height.

Formulation considerations

Polyols are excellent formulation tools to lower sugar and reduce calories. But, formulators need to remember that polyols are low-digestible carbohydrates (LDCs), grouped with other LDCs, such as resistant starches; oligosaccharides, such as polydextrose and fructooligosaccharides; polysaccharides, such as pectins, inulin and celluloses; and sugars, such as trehalose. Within this grouping and versus many fibers, many polyols are comparatively well-tolerated. Proper use will minimize tolerance concerns, and the correct choice of polyols to accomplish calorie and sugar reduction will result in an end product that processes easily, has a great appearance and is enjoyed by the consumer. 

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Ronald C. Deis, Ph.D., director, global sweetener development for Ingredion Inc., Westchester, IL, joined Corn Products Intl (now Ingredion) in 2007 when Corn Products acquired SPI Polyols, Inc., where he served as vice president of applications research and technical service. Deis has 35 years experience in R&D, working with carbohydrates and sweeteners in a number of applications, and has written articles (including over 15 years as a contributing editor for Food Product Design), contributed book chapters, and given presentations on calorie reduction, sugar reduction, fat reduction and glycemic-response reduction in foods. Current areas of concentration are high-potency sweeteners and polyols. Deis holds a Ph.D. in Food Science from Penn State University, an M.S in Microbiology from Miami University (Oxford, Ohio) and a B.S. in Biology from Wright State University,  Dayton, OH. He is a board member of Calorie Control Council, and is a member of IFT, AACC, and AACT. Click here for more information about Ingredion polyols.