On the transport and dynamics of disaccharides: H-bonding effect in sucrose and sucralose

Sucrose and sucralose are ubiquitous in foods and, as a consequence, they play a relevant role in our diet, with a significant impact on health. Due to their chemical similarities, these disaccharides are also relevant by fundamental issues, including the dynamic and structure in aqueous solutions. Despite their relevance for food industry, information about the effect of salts on the diffusion of both sucralose and sucrose is scarce. Moreover, studies aiming to explain how the substitution of hydrogens (in sucrose) by chlorines (in sucralose) affects the dynamics and the hydration of these compounds are missing in the literature. By using diffusion measurements and molecular dynamic (MD) simulations, we contribute to a better understanding of the H-bonds between the disaccharides and water molecules and, thus, of their solubility differences and sweetness perception. The effect of sodium chloride, and therefore of the ionic strength, on the dynamics and diffusion of both disaccharides was also evaluated.The limiting diffusion coefficient of sucralose is higher than that found for sucrose, thus indicating a lower hydration shell of the former, as well as a less affinity towards water molecules. In the presence of NaCl, the coupled diffusion shows that the interaction between the electrolyte and sucrose is stronger, highlighting the role of hydroxyl groups on the interaction with sodium ion, as it is confirmed by MD simulations.