DSC study of sucrose melting

An early endothermic peak at ∼150 °C was observed for crystalline sucrose by differential scanning calorimetry. The enthalpy at this temperature was found to vary with recrystallised sucrose from different sources. The addition of mineral salts to recrystallisation solutions decreased the enthalpy of the peak at around 150 °C, whereas the absence of salts increased it. The presence of organic solvents and polysaccharides in solution had a minor effect compared to the inorganic impurities. The peak was also depleted by increasing the amount of stirring and temperature at which recrystallisation was performed.

Typical DSC thermogram for recrystallised sucrose showing T1, ΔH1 and T2, ΔH2.Figure optionsDownload as PowerPoint slide