Erythritol

Like mannitol and sorbitol, erythritol (see here also) is an alditol - a molecule created by reducing the carbonyl group of the corresponding sugar (in this case, erythrose).

Note that erythritol appears to contain chiral carbons, but actually doesn't because it has a plane of symmetry between carbons 2 and 3. It is therefore not optically active.

See also: Derivatives of Monosaccharides