Structure-driven sugar-water interactions in aqueous solutions; insights from ATR-FTIR spectroscopy

Carbohydrates play essential roles in biological, atmospheric, and food-related systems, where their hydration characteristics regulate stability, reactivity, and macroscopic behavior. In this work, ATR-FTIR difference spectroscopy combined with spectral deconvolution was employed to elucidate how arabinose, galactose, and fructose modulate the hydrogen-bond network of water. Analysis of the integrated peak areas shows that sugar addition perturbs the ordered water structure and redistributes the populations of different hydrogen-bonded environments within the OH-stretch region, with fructose inducing the highest effect, followed by galactose and arabinose. As solute concentration increases, the progressive depletion of available water molecules enhances sugar-sugar interactions, further shaping the overall hydrogen-bonding landscape in bulk water. Moreover, fructose forms stronger hydrogen bonds with water relative to arabinose and galactose. These findings indicate that the hydration behavior of carbohydrates is governed predominantly by the number and spatial arrangement of hydroxyl groups rather than by the carbohydrate backbone, while the present approach enables a comparative and concentration-resolved analysis of hydrogen-bond environments across different sugars, providing molecular-level insights relevant to aqueous solution structure, biophysical hydration, and liquid-phase carbohydrate chemistry.