Thermal Properties and Phase Diagrams of Rare Sugars Isomaltulose and Allulose

Allulose and isomaltulose are rare sugars gaining popularity as alternatives to sucrose. These rare sugars behave differently from sucrose in their thermal properties and phase behaviors, which in turn later affect these same parameters in any product they may be used in. A firm comprehension of the thermal properties and phase behaviors of isomaltulose and allulose is therefore useful in determining the suitability and effectiveness of using these sugars as sucrose replacements in different confectionery applications. Moisture sorption isotherms for each sugar were determined, indicating that allulose has a higher affinity for water at relative humidities lower than that of sucrose and that isomaltulose remains relatively stable across a range of relative humidities. Phase diagrams were created for each sugar, displaying the phase state of each across a range of concentrations and temperatures. Results demonstrated that the physical properties of sucrose, allulose, and isomaltulose are different from one another.