Refractive Index, Viscosity, and Solubility at 30 °C, and Density at 25 °C for the System Fructose + Glucose + Ethanol + Water
ABSTRACT Commercial crystalline fructose is currently prepared by chromatographic separation of aqueous solutions of fructose and glucose followed by crystallization in either aqueous or aqueous−ethanol solutions. It may be possible to use one or more crystallization steps instead of the chromatographic process, thus producing crystalline product more directly. In this study the solubility, refractive index, and viscosity of solutions of fructose + glucose + ethanol + water were measured at 30 °C, and the densities of solutions with solvent concentrations of 40, 60, and 80 mass % ethanol were measured at 25 °C. These properties will be useful for crystallization studies for this system.
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ABSTRACT: New experimental data on the solubilities of d-fructose in the mixed solvents water/ethanol, water/methanol, and ethanol/methanol at 25, 40, and 60 °C are presented. These data were obtained using a standard, simple, and accurate experimental technique. Therefore, the database generated in our laboratory throughout a 4-year project now contains 205 solubility data points for systems with d-glucose, sucrose, and d-fructose in pure water, ethanol, and methanol and their mixtures. All of these data were correlated using the modified UNIQUAC, the entropic free-volume, and the original Flory−Huggins models, and the new parameters are given. The modified UNIQUAC model is the more accurate for the representation of the data. At the same time, predictions obtained with two different UNIFAC methods are compared.09/2001;
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ABSTRACT: The purpose of this investigation was to determine, using a capillary viscosimeter, kinematic viscosity data of aqueous solutions of ethanol and glucose, at several temperatures (from 20 up to 45ºC) and concentrations. Glucose solubility strongly depended on ethanol concentration allowing the kinematic viscosity study (from 5% up to 45% w/w ethanol concentration with variable glucose concentrations as a function of its solubility). Kinematic viscosity modelling with solution concentration and temperature simultaneously, based on previous models for respective binary systems, was successfully carried out. The estimated values by this model give low average deviations (2.62%) from the experimental data. Glucose solubility (at 25ºC) in alcohol solutions and index of refraction (at 20ºC) of ternary solutions were also determined and empirical models are proposed in order to evaluate both physical properties with high (R2 > 0.993 and > 0.991, respectively) accuracy.International Journal of Food Properties 10/2009; 12(4):834-843. · 0.88 Impact Factor
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ABSTRACT: At present, glucosamine is an important substance for its future use in food products to contribute therapeutical characteristics to the product. In the present paper, the viscosimetric behaviour of aqueous solutions of this solute has been carried out. For a deep characterization, the effect of composition and temperature have been analysed. Also the effect of addition of glucose upon the viscosity of the solution has been studied. The viscosimetric behaviour of aqueous solutions of glucosamine and the mixtures with glucose has been modelized with equations for one and two solutes obtaining suitable results.Journal of Food Engineering - J FOOD ENG. 01/2005; 68(3):403-408.