Molecular Theory of Sweet Taste

Abstract

THE molecular feature common to the many different sweet tasting compounds has been sought for many years¹. For the sugars, it was proposed^2–5 that the sweet unit is the glycol group, and that intensity of sweetness varied inversely with the degree to which glycol OH groups appear to be intramolecularly hydrogen bonded. It is now apparent that vicinal OH groups in the glycol unit need to be approximately gauche, or in a staggered conformation. Vicinal OH groups which are in the anti conformation apparently are too far apart to cause sweet taste. Glycol OH groups which are eclipsed probably participate in an intramolecular hydrogen bond which competitively inhibits interaction of glycol with the receptor site. These steric features of sweet and non-sweet sugar glycol units are shown in perspective in Fig. 1. Glycol conformational parameters, and the gross conformation of pyranose and furanose rings, have been used to explain the varying sweetness of the sugars^2–5.