Experimental Determination Methods And Model Fitting Of Solubility For Isomalt And Trehalose

With the development of the healthy diet culture, as a new food additives, functional sweeteners which points out the new direction of the sustainable development of food industry, have got the favor of people. If its solubility could be studied and predicted comprehensively, important basic data would be provided for the industrialization of functional sweeteners and its application in food industry and so on.The experimental materials for this work were isomalt and trehalose, their solubiliy in water+ethanol solvent system at different temperatures were determined. The solubility of isomalt in water+ethanol solvent system was measured with the mole fraction of water ranging from 0.00 to 1.00 at (288.15,298.15,308.15, and 318.15) K by using gravimetric method. The data were fitted using the simplified Jouyban-Acree model, and compared with the data previously measured by our group using the laser method. The advantages and disadvantages of the two methods were analyzed.The solubility of trehalose in water+ethanol solvent system was measured with the mole fraction of water ranging from 0.000 to 1.000 at temperatures from (288.15 to 318.15) K using the gravimetric method. There was a minimum point on each solubility curve at mole fraction of water ranging from 0.040 to 0.050. The Differential Scanning Calorimetry (DSC) measurement results showed that anhydrous trehalose (a white flocculent precipitate) appeared in the suspension at water content lower than the minimum point. While higher than that point, the crystals in the slurry were still hydrous polymorph which is granular-like. This demonstrated that the minimum point corresponds to the critical point of polymorphic transition. The solubility data at water content lower and higher than the critical points were nonlinear surface fitted separately using the combination version of the Jouyban-Acree and van’t Hoff models which is a three-dimensional model. The average relative deviation (ARD) values for trehalose solubility at water content lower and higher than the critical point were 25.71% and 11.62%, respectively, which shows the thermodynamic model fitted the data well especially for the latter.