Pure and Applied Chemistry

Abstract: The mechanistic understanding of sweet taste chemoreception has been advanced by the microscopic and macroscopic studies of sweetener­water interactions. This approach has led to the concept of water mobility as a key to interpreting sweetness. The apparent specific volume of a solution is a determinant of its taste quality, as sweetness is known to be confined to the range 0.51­0.71 cm³ g^-1. Thus, the "ideal" quality of the sugars is presumed to be due to their occupancy of the center of this range (i.e., 0.618 cm³ g^-1). Most sweeteners elicit off-tastes and flavors and exhibit different apparent specific volumes. This leads to the conclusion that taste quality is broadly determined by the packing characteristics of sweet molecules among water molecules and the compactness of their hydration shells, expressed as their apparent specific isentropic compressibilities. The role of water can, therefore, be applied in modern attempts to optimize sweet taste quality, and different food salts can be explored as useful taste modifiers. Salts interact more strongly with water structure than do any other taste solutes, and it emerges that the ionic charge density is an important criterion. Such studies show how sweetener formulations are likely to improve within the next decade.