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Title: Study of volumetric properties of binary aqueous solutions of selected natural and artificial sweeteners at various temperatures
Authors: Rashad, Muhammad
Keywords: Chemistry
Issue Date: 2015
Publisher: Government College University, Faisalabad
Abstract: This work presents investigations of the density, sound velocity, volumetric and acoustical behavior of binary aqueous solutions of some sweeteners namely acesulfame potassium, sodium cyclamate, sodium saccharin; D-mannitol, maltose, and poly sucralose at 293.15–318.15 K. The entire work was done at atmospheric pressure. The objective of study was to support building a suitable relationship among densities, sound velocities, sweeteners’ concentration and structural characteristics to explore sweetness response and molecular interactions in aqueous solution. Densities () and sound velocities (μ) have been measured as a function of concentration for aqueous solutions at 293.15–318.15 K and atmospheric pressure using electronic vibrating U tube density and sound velocity meter (DSA 5000M). Solutions of acesulfame- K, cyclamate- Na and saccharin- Na were treated as electrolytes, while D- mannitol, maltose and poly sucralose were considered as non-electrolytes. The results obtained were used to compute their apparent and partial Molal volumes; isentropic apparent and partial Molal isentropic compressibilities and compressibility hydration numbers have been calculated and reported. The apparent Molal volume, (ΦV) of electrolytes indicates negative deviations from Debye-Huckel limiting law. The values obtained for, ΦV, at given temperatures and concentrations may be used as an indicative for the strength and intensity of the ion/solute–ion/solute and ion/solute-solvent interactions. The partial Molal volume (ΦV°) indicates hydrophilic interactions dominating in aqueous solutions of studied sweeteners. Furthermore, apparent specific volumes (ASV) of the ions/solutes were calculated and it was found that these values of the investigated solutes lie between the reported values for sweet substances (0.51 – 0.71 cm3g-1) except for poly sucralose which might behaves differently due to its long chain structure. The partial Molal expansibility (ΦE°), Hepler’s constant (∂2V0/∂T2) and thermal expansion coefficient (a°) have been estimated and correlated to the effect of temperature on solution behavior. The isentropic apparent Molal compressibility (ΦK(s)) and compressibility hydration number (nH) conferred pre-dominance of ion/solute-solvent interactions, whereas partial Molal expansibility and related standards predicted structure making or breaking behavior of studied sweeteners. The Hepler’s constant values for sodium cyclamate and maltose x were negative which associated with the water structure breaking behavior of these sweeteners. The thermodynamic parameters like Apparent Molal volume (ΦV), partial Molal volume (ΦV°), apparent specific volume (ASV), partial Molal expansibility (ΦE°), isentropic apparent Molal compressibility (ΦK(s)) and related constants provided clear distinctions and variable hydration behavior and sweetness response from class to class, structural variability and molecular masses. So, as a whole this study provided new insights in elucidation of mechanistic differences between sweeteners and their mode of interactions.
Gov't Doc #: 16720
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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