Computer modelling studies of the water-structuring properties of carbohydrates and the sweetness response

Molecular dynamics calculations have been carried out for a variety of carbohydrates in aqueous solvent to ascertain their water-structuring capabilities. Radial distribution functions have been calculated for oxygen, carbon and hydrogen atoms in a range of different environments. These functions are able to reveal quite different and distinctive behaviour of the solvent around the atom types and in particular can distinguish between hydrophilic and hydrophobic hydration effects. The arrangements of water molecules around the different hydroxide groups in the sweet tasting α-d-mannopyranose and the bitter tasting anomer β-d-mannopyranose have been calculated and the radial distribution functions show significant differences between hydroxyl groups in the same molecule and the equivalent hydroxyl groups in different molecules. Methods are assessed for the summation of hydrogen bonds around the carbohydrate oxygen atoms. The results of the molecular dynamics calculations are consistent with previous experimental and theoretical data about the taste properties of these two molecules.