Apparent molar volumes and tastes of molecules with more than one sapophore

Abstract

The taste qualities of molecules known to generate more than one type of taste (multisapophoric molecules) or known to contain more than one sapophore (potentially multisapophoric molecules) have been examined by physical methods in an attempt to explain their dominant taste response. The physical parameters examined were intrinsic viscosity, Huggins constant, apparent molar volume and apparent specific volume. The apparent specific volume was found to discriminate between the four basic tastes (salt < ˜0.33, sour ˜0.33 to ˜0.52, sweet ˜0.52 to ˜0.71 and bitter ˜0.71 to ˜0.93) when applied to 48 unisapophoric molecules. The corresponding values for 18 multisapophoric molecules lie close to the appropriate primary taste interface. The apparently anomalous behaviour of six other molecules is discussed. It is suggested that in order to elicit a particular basic taste a molecule must contain the appropriate sapophore and interact with water so as to achieve a critical specific volume. These results are consistent with the idea that specific receptors for the four taste modalities reside at different layers of the taste epithelium.