Rotational Spectroscopy As a Tool to Characterize Sweet Taste: the Study of Dulcin

According to old theories of sweetness, the perception of sweet substances is closely linked to the arrangement of atoms within them. To assess the validity of these theories, we conducted an analysis of the structure of the artificial sweetener dulcin for the first time, utilizing microwave spectroscopy and a laser ablation source. These techniques have enabled the identification of two conformers, which are stabilized by an intramolecular hydrogen bond between the amino group and the phenyl ring. The observed conformations were examined in light of the Shallenberger-Acree-Kier molecular theory of sweet taste, and they align with the hypothesized criteria. Furthermore, the study illustrates how conformational relaxation can alter the equilibrium conformational distribution, resulting in the absence of certain conformers in the conformational landscape. We provide experimental evidences that support the old theories of sweetness using dulcine as the archetypal molecule by means of Laser Ablation Chirped Pulse Fourier Transform Microwave Spectroscopy (LA-CP-FTMW) technique. Eluciding the structure of dulcin, we can decipher if it meets the structural requirements that a sweet molecule need to have according to the postulated theories. image