Effect of protic ionic liquid on the volumetric properties and taste behaviour of sucrose

The volumetric properties and taste behaviour of sucrose in aqueous solutions of a protic ionic liquid (3-hydroxypropylammonium acetate) have been studied at temperatures, T=(293.15-318.15)K and at atmospheric pressure. Apparent molar volumes, V2,ϕ, apparent specific volumes, ASV, apparent molar isentropic compressibilities, Ks,2,ϕ, and apparent specific isentropic compressibilities, ASIC, were calculated from measured density, ρ and speed of sound, u data. Partial molar volumes, V2(°), and partial molar isentropic compressibilities, Ks,2(°) at infinite dilution, transfer parameters (ΔtV2(°) and ΔtKs,2(°)), expansion coefficients, [(∂V2(°)/∂T)P and (∂(2)V2(°)/∂T(2))P], interaction coefficients, (YAB and YABB) and hydration numbers, Nw, were also evaluated and discussed in terms of solute-cosolute interactions. Further, the effect of protic ionic liquid on the taste behaviour of sucrose has been discussed from ASV and ASIC parameters, as these parameters, which are sensitive to solvation behaviour of solute, are divided into four basic taste qualities occupying certain ranges.

Calorimetric and theoretical study of the interaction between some saccharides and sodium halide in water

Dilution enthalpies and mixing enthalpies of sodium halide and some saccharides (glucose, galactose, xylose, arabinose, fructose, and sucrose) in aqueous solution were determined by calorimetric measurements at 298.15 K. The values were used to determine enthalpic pair interaction parameters. Combined with Gibbs energy pair parameters, entropic pair interaction parameters were also obtained. Theoretical calculations at the B3LYP/6-311++G(d,p) level were carried out to provide the information of structures and thermodynamic functions. The information reveals the thermodynamic essence of the interactions between sodium halide and saccharides in aqueous solutions. The experimental results and theoretical calculations show that the sign of enthalpic pair interaction parameter 2υh(ES) is determined by the direct interaction between saccharides and ions, whereas the difference in value of 2υh(ES) for different saccharides or electrolytes depends on the partial dehydration of saccharides or anions in aqueous solution. The difference in value of entropic pair interaction parameters depends partly on the different dominant interactions in the process of partial dehydration of saccharides or ions. An enthalpy-entropy compensation relationship was observed for the sodium bromide-aldopyranose-water systems. Remarkably, it can be conjectured that the hydration entropy of glucose is lower than for other monosaccharides. Perhaps it is one of the reasons why glucose plays an important role in living organisms rather than other monosaccharides.