The Structural Signs of Sweetness in Artificial Sweeteners: A Rotational Study of Sorbitol and Dulcitol.

A gas-phase study on the artificial sweeteners sorbitol and dulcitol has been carried out for the first time by using a combination of chirped-pulse Fourier-transform microwave (CP-FTMW) spectroscopy and laser ablation (LA). The isolation conditions provided by the supersonic expansion reveal the intrinsic conformational structures of these sweeteners. The three and five observed conformers for sorbitol and dulcitol, respectively, are stabilized by networks of cooperative intramolecular hydrogen bonds between vicinal hydroxyl groups in clockwise or counterclockwise arrangements. Suitable places in the structure of seven out of eight conformers identified for both polyalcohols meet the requirements of the glucophore proposed by Shallenberger and Acree's molecular theory of sweet taste. Present results provide the first linkage between sweetness and structure in sugar alcohols.