Polyols are compounds with multiple functional hydroxyl groups bound to a carbon atom. They are alcohols, and are primarily used by two industries, food science and chemistry, depending on their composition. These compounds can be naturally or artificially produced, and one source of natural polyols is vegetable oil. Polyols derived this way are known as natural oil polyols (NOP), and are classified as biobased products in the United States. This means that a large part of their structure is composed of natural and renewable parts.
In the food science industry, the most common use of polyols are as sugar replacements. They are known as sugar alcohols, and, although they have the structure of alcohol, they mimic the sweetness of sugar when added to food. Sugar alcohols have a lower calorie count than true sugar, and are often used in sugar-free or diet foods and drinks. These polyols are also less sweet than naturally-occurring sugar, and a potent artificial sweeter is generally added to compounds which contain sugar alcohols.
One product that almost invariably contains sugar alcohols is chewing gum. They are added to gum because they are not broken down by either saliva or chewing action, and therefore do not cause tooth decay. Some of the most common sugar alcohols are maltitol, sorbitol and xylitol. All of these have different ratings of sweetness. Sorbital is 60% as sweet as true glucose, while maltitol rates at 75%, and xylitol matches the sweetness level of natural sugar. In the United States and Canada, products which are labeled as sugar-free must list the amounts of sugar alcohol they contain.
Sugar alcohols are not entirely absorbed by the body, which is part of the reason they have a lesser caloric impact. They are eventually excreted, but it is possible to have a build-up of these polyols in the intestines, which causes them to ferment. This, in turn, can cause pain and bloating. The term sugar alcohol can also be misleading, since, although these compounds do have an alcohol structure, they cannot produce a state of intoxication.
Polymer chemistry is the other area in which polyols are often used. The multiple hydroxyl groups contained in the compound are used for organic reactions — most often as reactants for the purpose of creating polymers. These polymers are then used to create items like shoe soles, Spandex fabrics, mattresses, and foam insulation for refrigerators and freezers. NOPs are also being used to create commercial substances, most notably polyurethane products, such as car seats and headrests.