Structure, sweetness and solution properties of small carbohydrate molecules

Abstract

The sweetness of small carbohydrate molecules in relation to their structure has been under investigation for several years. Tentative glucophores can now be assigned to some structures and the sweetness effect is thought to originate in a hydrogen bond between stimulus molecule and sweet receptor. A recent study of solution properties of small carbohydrates in relation to sweetness aims to examine the hydrogen bonding between water molecules and sweet solutes as a preliminary stage of taste chemoreception. Hydrated sugar molecules are presumed to accede to receptors before binding with the receptors is able to occur. Apparent molar and apparent specific volumes give indications of the effective size of sapid solute and its compatibility with water structure. Axial and equatorial hydroxy groups differ in their effects according to their location in the hexopyranose structure. Analogous structures exhibit analogous apparent molar volumes; these effects may be related to the differences of sweetness intensity between some sugar structures and the bitterness of others. Although there is yet no simple relationship between sweetness intensity and apparent molar volume (^ϕV), it is possible that (^ϕV) does govern the taste dominance of one molecular species in binary mixtures. Moreover, apparent specific volumes of a range of sapid solutes seem to correlate with taste quality.