The fragile character and structure-breaker role of alpha,alpha-trehalose: viscosity and Raman scattering findings

Results of viscosity and Raman scattering measurements on trehalose aqueous solutions are presented. They provide evidence that the trehalose-water system shows a very fragile character, i.e. a great structural sensitivity to temperature and concentration changes. In addition, to get some insight into the effects of trehalose on the hydrogen-bond network of water, we investigate the intramolecular O-H stretching mode, which is particularly sensitive to environmental modifications. For the O-H stretching region analysis, a decomposition of the isotropic spectra into an `open' and a `closed' contribution has been employed. The procedure suggests that trehalose promotes a destructuring effect on the tetrahedral H-bond network of pure water, imposing on adjacent water molecules positions and orientations incompatible with the crystallization process.