Hexitols

Hexitols are alditols with six carbon atoms, a class of sugar alcohols formed by the selective hydrogenation of hexose sugars. Each hexitol contains six carbons and multiple hydroxyl groups, and they are typically crystalline, highly soluble in water, and sweet-tasting. They are used as sugar substitutes and humectants, often providing fewer calories and a lower glycemic impact than sucrose, and are common in sugar-free foods and pharmaceutical formulations.

The best-known hexitols are sorbitol (D-glucitol) and mannitol (D-mannitol). Dulcitol is the common name for galactitol. Other stereoisomers have been described, including iditol and allitol. In total, eight stereoisomers are possible for aldohexitols, arising from the different configurations of the remaining three chiral centers after reduction of the aldehyde group.

Natural occurrence and production: Hexitols occur in small amounts in fruits and vegetables. Industrially, they are produced by catalytic hydrogenation of hexose sugars such as glucose or mannose.

Applications and safety: As sweeteners, hexitols provide sweetness with reduced caloric value and lower dental erosion. Sorbitol and mannitol are used as excipients and, in some cases, as osmotic laxatives; excessive intake can cause gastrointestinal symptoms. They generally have a lower glycemic index than sucrose, but they can affect blood glucose and should be consumed in moderation by individuals with carbohydrate-related disorders. Hexitols are related to other sugar alcohols, such as xylitol, a pentitol.