Electrokinetic potential is an important property of colloidal particles and, regarding the fact that it is a well defined and easily measurable property, it is considered to be a permanent characteristic of a particular colloidal system. In fact, it is a measure of electrokinetic charge that surrounds the colloidal particle in a solution and is in direct proportion with the mobility of particles in an electric field. Gouy-Chapman-Stern-Graham's model of electric double layer was adopted and it was proven experimentally that the addition of Cu++ ions to sugar beet pectin caused a reduction in the negative electrokinetic potential proportional to the increase of Cu++ concentration. Higher Cu++ concentrations increased the proportion of cation specific adsorption (Cu++ and H+) with regard to electrostatic Coulombic forces. Consequently, there is a shift in the shear plane between the fixed and diffuse layers directed towards the diffuse layer, i.e. towards its compression and decrease in the electrokinetic potential or even charge inversion of pectin macromolecules
The paper describes a study of osmotic dehydration of red cabbage in sugar beet molasses of different concentrations (40, 60 and 80%) at 50°C and under atmospheric pressure. The best results were obtained at the sugar beet molasses of 80% as an osmotic medium. The most important kinetic parameters of the process were determined: water loss, solid uptake, weight reduction, normalized solid content and normalized moisture content. The kinetic parameters were determined after 1, 3 and 5 hours. Mass transfer coefficients were calculated using Hawkes and Flink's model and the results indicate that the diffusion of water and solids was the most intensive during the first three hours of dehydration
The applicability of Peleg equation was examined for the description of mass transfer during osmotic dehydration (OD) of apple in sugar beet molasses. Mass transfer was investigated in terms of water loss (WL) and solid gain (SG), during OD in 40-80% sugar beet molasses solutions, at 45, 55 and 65ºC. High regression coefficients obtained for Peleg constants (R2>0.975) indicate good fit to the experimental data. The Peleg rate constant varied from 0.144 to 0.785 (g/g i.s.w.) and from 2.006 to 4.436 (g/g i.s.w.) for WL and SG, respectively. The Peleg capacity constant varied from 1.142 to 1.553 (h g/g i.s.w.) and from 8.254 to 11.930 (h g/g i.s.w.) for WL and SG, respectively. The equilibrium WL∞ and SG∞ were estimated using the Peleg model. In addition, the activation energy (Ea) for WL and SG was determined from the relationship between the Peleg rate constant and Arrhenius equation
The osmotic dehydration process of carrot in sugar beet molasses solutions (40, 60 and 80%), at three temperatures (45, 55 and 65°C) and atmospheric pressure, was studied. The main aim was to investigate the effects of immersion time, working temperature and molasses concentration on mass transfer kinetics during osmotic dehydration. The most important kinetic parameters were determined after 20, 40, 60, 90, 120, 180, 240 and 300 min of dehydration. Diffusion of water and solute was the most intensive during the first hour of the process and the maximal effect was observed during the first 3 hours of immersion. During the next two hours of dehydration, the process stagnated, which implied that the dehydration time can be limited to 3 hours
In sugar industry there is a problem of the presence of undesirable macromolecules compounds such as pectin in sugar beet juice. The affinity of calcium ions commonly used in the sugar industry for the removal of pectin from the sugar beet juice is relatively small. Coagulation and precipitation of pectin can be performed by process of discharging that is chemically induced. Compounds with di- and trivalent cations such as pure CuSO4, Al2(SO4)3 or their mixtures can be applied for clarification of pectin colloidal systems. According to data from the order of pectin selectivity to divalent metal ions, Cu2+ ions are the first order of ion binding. Also, aluminum sulfate is commonly used in the waste water treatment. Two model solutions of pectin whose concentration corresponds to the concentration of these macromolecules in sugar beet juice (0.1% w/w) are investigated. Using a method of measuring zeta potential, it was proven for both investigated pectin that fewer quantities of Cu2+ ions compared to the values of Al3+ ions are needed to reach zero zeta potential. In all the investigated coagulants and their mixtures, zeta potential has changed the sign. In experiments with mixtures has been shown that pure salts showed better coagulation properties. The reduced strength of binding of cations in the case of most of the applied mixture of Cu2+ and Al3+ ions, can be explained by the mutual competition of these ions for the adsorption site (COO- groups) on the surface of macromolecules. Mixture with approximately equal shares of ions Cu2+ and Al3+ had the most unfavorable coagulation ability (ion antagonism). Mechanism of discharge as well as the model of double electric layer surrounding pectin macromolecules in the presence of mixtures of Cu2+ and Al3+ ions are suggested. However, due to possible undesirable effects of CuSO4 on food processing, Al2(SO4)3 is proposed instead of traditional coagulant CaO, not only because of lower consumptions of coagulants but owing to protection of the environment
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.