Erythritol is a sugar alcohol, also known as a polyol, that is used as a sugar substitute. It occurs naturally in some fruits, such as pears and watermelons, but most commercial erythritol is produced by fermenting glucose derived from cornstarch or wheat starch. Erythritol has gained popularity as a low-calorie sweetener due to its unique properties and health benefits.

Here are some key points about erythritol:

1. Sweetness and Taste: Erythritol has a sweet taste similar to sugar but with only about 70% of the sweetness. It does not have the aftertaste associated with many other sugar substitutes, such as stevia or artificial sweeteners like aspartame or saccharin.

2. Low Calorie: Erythritol is virtually calorie-free. Although it is a carbohydrate, it has a minimal impact on blood sugar levels and does not provide significant calories to the body. It is often used in sugar-free and reduced-calorie products as a way to provide sweetness without the added calories.

3. Natural and Tooth-Friendly: Erythritol is considered a natural sweetener since it occurs naturally in some foods. It is also non-cariogenic, which means it does not promote tooth decay. Unlike sugar, erythritol cannot be fermented by bacteria in the mouth, thus reducing the risk of dental cavities.

4. Digestibility and Digestive Tolerance: Erythritol is absorbed into the bloodstream and excreted unchanged in the urine, without being metabolized. It is not fully digested by the small intestine, leading to fewer side effects commonly associated with other sugar alcohols, such as bloating and digestive discomfort. Most people can tolerate erythritol well, even in high amounts.

5. Applications: Erythritol is used as a sugar substitute in a variety of food and beverage products. It is found in sugar-free chewing gums, candies, desserts, beverages, and baked goods. It can be used as a direct replacement for sugar in recipes, although it may not provide the same structure and texture as sugar due to its different properties.

6. Safety: Erythritol is generally recognized as safe (GRAS) by regulatory authorities, including the U.S. Food and Drug Administration (FDA) and the Joint Expert Committee on Food Additives (JECFA). It does not have a measurable impact on blood sugar levels and is considered safe for consumption by people with diabetes.

However, as with any food ingredient, individual sensitivities or allergies can occur. It's always a good idea to consult with a healthcare professional or read product labels if you have concerns or specific dietary requirements.