What Exactly Are Polyols (Sugar Alcohols)?
Polyols are a class of organic compounds containing multiple hydroxyl ($−OH$) groups. While they are technically alcohols from a chemical standpoint, they do not contain ethanol and are distinct from alcoholic beverages. The term can refer to different substances depending on the context; in food science, it specifically designates "sugar alcohols" used as low-calorie sweeteners. For commercial use, polyols are manufactured by hydrogenating common sugars or starches.
Polyols as Bulk Sweeteners
Polyols are considered bulk sweeteners because, unlike high-intensity sweeteners, they are used in similar volumes to sugar. This bulking property provides texture and body to food products, which is crucial for recreating the mouthfeel of sugar-sweetened items. Their mild sweetness is often complemented by high-intensity sweeteners to achieve the desired level of sweetness.
The Benefits of Using Polyols
Polyols offer several advantages over traditional sugar, making them popular in many food and pharmaceutical products.
- Low Calorie Content: Since polyols are incompletely absorbed by the body, they contribute fewer calories per gram than sugar, with specific values varying by type.
- Dental Health: Polyols are non-cariogenic, meaning they are not readily fermented by oral bacteria into enamel-damaging acids. Xylitol, in particular, is noted for its dental benefits and is often found in sugar-free gum.
- Lower Glycemic Impact: Because they are absorbed more slowly, polyols cause a smaller, more gradual rise in blood glucose levels, making them suitable for diabetics and those managing blood sugar.
- Functional Properties: Beyond sweetness, polyols can provide moisture retention (humectancy), inhibit browning reactions, and offer a pleasant cooling sensation.
Polyol Sweetness and Calories Comparison
| Polyol | Relative Sweetness (vs. Sucrose = 100%) | Calories per Gram |
|---|---|---|
| Erythritol | 60–80% | 0–0.2 kcal/g |
| Sorbitol | 50–70% | 2.6 kcal/g |
| Xylitol | 100% | 2.4 kcal/g |
| Maltitol | 50–90% | 3 kcal/g |
| Isomalt | 45–65% | 2 kcal/g |
| Sucrose | 100% | 4 kcal/g |
Potential Drawbacks and Considerations
While polyols are beneficial for many, they are not without potential downsides, especially when consumed in large amounts. The incomplete absorption that contributes to their low-calorie profile can also lead to gastrointestinal issues.
- Digestive Discomfort: Excessive polyol intake can cause bloating, gas, and diarrhea, particularly in individuals with irritable bowel syndrome (IBS). This effect is dose-dependent and varies by individual sensitivity.
- FODMAPs: Polyols are a component of the Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP) group, which can trigger symptoms in sensitive individuals.
- Cooling Effect: Some polyols, like xylitol and erythritol, produce a cooling sensation in the mouth. While pleasant in mints and gums, this effect can be undesirable in baked goods or other products.
Common Polyols Found in Food
- Xylitol: Found in sugar-free gum, candy, and toothpaste due to its dental health benefits and sweetness comparable to sucrose.
- Erythritol: A very low-calorie polyol often used in keto and sugar-free products, known for its mild taste and strong cooling effect.
- Sorbitol: Naturally occurring in fruits like apples and pears, sorbitol is a humectant and texturizer used in candies, baked goods, and other confections.
- Maltitol: Often used as a sugar substitute in chocolates and baked goods because its sweetness and properties closely mimic sugar.
The Role of Polyols in Food Formulation
Food manufacturers leverage the diverse properties of polyols to achieve specific results beyond simple sweetness. They are used as bulking agents, texturizers, and moisture-control agents. For example, in ice cream and frozen desserts, polyols lower the freezing point, improving texture and scoopability. The choice of a specific polyol depends on the desired end-product characteristics, such as viscosity, heat stability, and browning. When formulated correctly, polyols allow for the creation of tasty, sugar-free, or reduced-sugar alternatives that satisfy consumer demand for healthier options. For more detailed information on their industrial applications, the Calorie Control Council provides a comprehensive overview of polyol usage in food.
Conclusion
To definitively answer "Is polyol a sweetener?" in the dietary context: yes, polyols are a category of carbohydrates widely used as bulk sweeteners, but they are not sugars. Known as sugar alcohols, they offer a host of benefits including lower calories, reduced glycemic impact, and dental health protection. However, moderation is key, as excessive consumption can lead to gastrointestinal distress. Their varied functional properties make them invaluable to the food industry for creating appealing sugar-free and reduced-sugar products, but their specific characteristics, such as a cooling effect, must be carefully managed depending on the application.
