Molecule of the Month

May 2007: Sorbitol

Sorbitol was discovered in 1872 by a French chemist named Joseph Boussingault. He isolated the molecule from the juice of mountain-ash berries. In 1937, sorbitol became available commercially from Atlas Powder Company (now known as SPI Polyols, Inc.). It is manufactured from glucose by adding hydrogen using a catalyst, such as nickel. The glucose is obtained from corn starch.

Sorbitol is used as a sweetener in “sugar-free” chewing gum, hard candy, mints, and baked goods. It is roughly 60% as sweet as cane sugar. Sorbitol’s advantages are that it is safe for diabetics and that it does not promote tooth decay. However, it is not “low calorie”, since each gram of sorbitol provides 4 Calories, the same as cane sugar.

Sorbitol and its isomer mannitol are used in the manufacture of pharmaceuticals. Both molecules have the formula C₆H₁₄O₆; the only difference is the spatial orientation of the hydroxyl group on the second carbon. As a result of this difference, sorbitol has an affinity for moisture, while mannitol is stable to moisture. Sorbitol’s affinity for water makes it useful as a humectant (an ingredient that promotes moisture retention).

Megan Brown