Water Dynamics and Structural Relaxation in Concentrated Sugar Solutions

The collective dynamics of concentrated aqueous solutions of the three well-known homologous disaccharides, namely, maltose, sucrose and trehalose, have been studied in an unexplored frequency region by Brillouin ultraviolet light scattering, as a function of temperature and concentration. In trehalose solutions, for water concentrations close to the sugar hydration number, the structural relaxation time above the freezing point of water proves to be 10 % smaller than in maltose/sucrose solutions, presaging a different reorganisation of the sugar matrix. This effect could help in reducing both desiccation stresses and ice formation in anhydrobiotic organisms. The relevance of this behaviour in bioprotection is briefly discussed.