“Sugars can be classified as monosaccharides, disaccharides or mixtures, such as corn syrup. The key to using polyols for sugar reduction is to select a polyol with similar structure and functional properties as the sugar that you are replacing,” said Peter Jamieson, MSc, Principal and Food Scientist, Atlas Point Technical Services, in his presentation “On Trend Ingredients: Polyols Properties, Labeling & Emerging Areas of Interest.”
Sucrose is the gold standard, because it is the sweetener to which other sugars are most often compared. Sucrose has unique properties, including its sweetness profile, solubility, melting point characteristics and crystallization characteristics. “Trying to replace sucrose is challenging, but polyols or sugar alcohols work well,” said Jamieson.
Polyols are metabolized differently than traditional sugars and carbohydrates. They have a lower glycemic response, lower calories and are also non-cariogenic. Polyols also provide excellent bulk, whereas high-potency sweeteners do not, so polyols can typically be used as a one-for-one replacement for other sweeteners in traditional foods.
Glucose has a reactive aldehyde group. The polyol sorbitol is similar in structure, but the aldehyde has been replaced by a hydroxyl group. This change makes sorbitol no longer recognized as a sugar for nutrition labeling. Replacing traditional sweeteners with polyols can enable products to make nutritional claims, including “no sugar added,” “reduced sugar” or “sugar free.”
Monomers with a single carbohydrate unit (e.g., glucose and fructose) include sorbitol, mannitol, xylitol and erythritol. Dimers with two carbohydrate units (e.g., sucrose and maltose) include maltitol, lactitols and isomalt. Mixtures include maltitol syrup and polyglycitol syrups. Polyols with more than 50% maltitol are called “polyglycitol syrups” and function more like high-DE corn syrups.
Polyols are caloric sweeteners. For example, maltitol has 2.1 calories per gram. They are “carbohydrates,” but they are not recognized as “sugars” or “added sugars” on the nutrition panel. You must call them out in the nutritional panel as “sugar alcohols” when making a sugar claim.
Jamieson explained some of the physical characteristics of polyols. Polyols are non-reactive and very stable at high temperatures. Polyols do not react with colors, flavors or actives. They do not participate in Maillard browning, which can be either a positive or negative attribute, depending on the application.
Generally, polyols have a negative heat of solution, so energy is being absorbed, resulting in a cooling sensation. Erythritol has a heat of solution of -42, compared to sucrose with a -4. When replacing sugar in chocolates, too much erythritol can make milk chocolate taste like mint chocolate.
Solubility in water is a key attribute that affects performance in baked goods, confectionery, beverages and variegates. Polyols have a wide range of solubility. Sorbitol is very soluble and is often used as a humectant. In contrast, mannitol is not very soluble.
Molecular weight of polyols affects viscosity in confections; freeze point depression in ice creams; and starch gelatinization point in baked goods. When replacing sucrose with a molecular weight of 342, good choices would be maltitol or isomalt, which both have a similar molecular weight.
Relative sweetness is important, especially as companies are tending to minimize use of high-potency sweeteners. Note that xylitol has the same sweetness as sucrose, while lactitol is only 40% as sweet.
Polyols are part of the family of low-digestible carbohydrates (LDC) that also includes polysaccharides, resistant starches and rare sugars. Rare or low digestible sugars include allulose, tagatose and isomaltulose. All LDCs have some degree of impact on the digestive tract. Some have an effect on osmotic laxation, while others impact fermentation by microflora in the GI. Individuals have different responses to LDCs and can adapt to increased levels of LDC in the diet.
A current trend is to focus on sugar reduction, rather than total sugar replacement. The goal should be to deliver a good eating experience.
“On Trend Ingredients: Polyols Properties, Labeling & Emerging Areas of Interest,” Peter Jamieson, MSc, Principal and Food Scientist, Atlas Point Technical Services