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Equilibrium data were obtained for aqueous two-phase systems composed of ionic liquid (IL) and two inorganic salts (dibasic potassium phosphate, K2HPO4, and tripotassium phosphate, K3PO4) at 298.15 K. The evaluated ionic liquids were 1-butyl-3-methylimidazolium methanesulfonate ([C4mim][CH3SO3]), 1-butyl-3-methylimidazolium chloride ([C4mim][Cl]), and 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]). Equilibrium curves of salt and ionic liquid were determined. Additionally, each curve was fitted into three mathematical models. The aqueous two-phase system composed of the IL [C2mim][Cl] required a lower mass fraction of IL and salt to form the systems than the other two systems studied in this work containing [C4mim][Cl] and [C4mim][CH3SO3]. Furthermore, the type of inorganic salts studied did not affect the equilibrium curves for the same ionic liquid.

A green and sustainable method has been developed to extract anthocyanins from broken black rice (BBR) using aqueous solutions of poly(ethylene glycol) (PEG). The effects of time, PEG concentration, temperature, BBR mass, and PEG molar mass were investigated using multivariate experimental designs. Time and temperature were not significant in the studied range and PEG 1500 was the most suitable. Under the optimized conditions, the anthocyanin concentration was 130.7 mg 100 g−1. The stability of the extract was higher at 25 °C and pH 5.0, with a reduction in absorbance (λmax = 455 nm) of only 7.14% after 60 days. The extract was applied in a colorless soap, and the color remained stable for 60 days (greater reduction in absorbance of 15.5% at 40 °C, λmax = 497 nm), indicating its potential for direct application in products of industrial interest. The method was also effective to extract anthocyanins from the husk and bran of black rice, with concentrations of 148.1 and 883.2 mg 100 g−1, respectively. In comparison with conventional methods for extracting anthocyanins, the proposed new technique offers the advantages of efficiency, simplicity and low cost, with the difference in extract concentration being obtained with methanol acidified with HCl of only 11%.

The present study includes measurements of the phase composition, density, and refractive index of aqueous two-phase systems of poly(ethylene oxide) 1500 (PEO1500) + sodium thiosulfate + H2O at (28...

The phase compositions in liquid−liquid equilibria of aqueous two-phase systems (ATPS) composed of the poly(ethylene oxide)− poly(propylene oxide)−poly(ethylene oxide) (PEO−PPO−PEO) triblock copoly...

The partitioning of the whey protein lactoferrin, which is an iron transporter glycoprotein, in an aqueous two-phase system composed of poly(ethylene glycol) (PEG) and sodium citrate was evaluated. Equilibrium data at 25 °C were determined for each system studied using PEG with a molar mass of 1000 and 4000 g·mol1 at pH values of 5.5, 6.5, and 7.5. An increase in the molar mass of the polymer promoted the expansion of the two-phase region and caused the migration of the lactoferrin to the salt-rich bottom phase. An increase in pH also led to the expansion of the biphasic region. However, changing the pH over the tested range slightly affected protein partitioning. Lactoferrin recovery percentages greater than 94% were observed for all of the systems evaluated. The results indicated that lactoferrin can be successfully partitioned in an aqueous two-phase system formed of 14% (w/w) PEG and 10% (w/w) sodium citrate at pH 5.5 and 25 °C. The protein was concentrated 1000-fold in the salt-rich bottom phase in this system., Brazilian agencies FAPESB,CNPq, and FAPEMIG for their financial support

Phospholipases comprise a group of enzymes with applications in the thermal stability and emulsifying capacity of food formulations. In this work aqueous two-phase systems (ATPS) were used to extract phospholipase A 2 (PLA 2 ) from raw porcine pancreas and snake venom at 25 °C. PLA 2 was partitioned into ATPS composed of inorganic salts, water and polyethylene glycol. We determined the partition coefficient, recovery factor, purification factor, enzyme activity and emulsifying activity for the enzyme extracted with the different ATPS tested. The highest partition coefficient ( K p = 81.7) and the highest theoretical recovery percentage of PLA 2 in the top and bottom phases of the systems were obtained from the pancreas extract. The highest recovery percentage in the top phase was obtained in a system with PEG1500/Na 2 SO 4 /H 2 O. Pearson correlation analysis between the ATPS descriptor parameters and the recovery and partitioning parameters of PLA 2 showed significant, albeit small, correlation between molar mass and PEG phase volume. Furthermore, Principal Component Analysis showed that the best system for PLA 2 purification was with ATPS PEG1500/Na 2 SO 4 /H 2 O. In addition to preserving enzyme activity, the ATPS provided a high partition coefficient of PLA 2 (81.67%) and can be considered a viable technique for pre-purification of PLA 2 .

The study of protein interactions has generated great interest in the food industry. Therefore, research on new supramolecular structures shows promise. Supramolecular structures of the whey proteins {\alpha}-lactalbumin and glycomacropeptide were produced under varying heat treatments (25 to 75 {\deg}C) and acidic conditions (pH 3.5 to 6.5). Isothermal titration calorimetry experiments showed protein interactions and demonstrated that this is an enthalpically driven process. Supramolecular protein structures in aqueous solutions were characterized by circular dichroism and intrinsic fluorescence spectroscopy. Additional photon correlation spectroscopy experiments showed that the size distribution of the structures ranged from 4 to 3545 nm among the different conditions. At higher temperatures, lower pH increased particle size. The foamability of the supramolecular protein structures was evaluated. Analysis of variance and analysis of regression for foaming properties indicated that the two-factor interactions between pH and temperature exhibited a significant effect on the volume and stability of the foam., Comment: 9 pages, 5 figures

We investigated the extraction behavior of Cu(II) in the aqueous two-phase system (ATPS) formed by (L35+MgSO(4)+H(2)O) or (L35+(NH(4))(2)SO(4)+H(2)O) in the presence of the extracting agent 1-(2-pyridylazo)-2-naphthol (PAN). At pH=3 and a PAN concentration of 0.285 mmol kg(-1), both ATPS lead to the effective separation of Cu(II) from other metallic ions (Zn(II), Co(II), Ni(II) and Fe(III)). High separation factors range between 1000 and 10,000 were obtained for the extraction of Cu(II) and concomitant metallic ions. This ATPS was used for the extraction of Cu(II) from a leached ore concentrate with a extraction percentage of 90.4 ± 1.1%; other metals were mainly located in the bottom phase.

The separation of Cd and Ni from Ni–Cd batteries using an aqueous two-phase system (ATPS) composed of copolymer L35, Li 2 SO 4 and water is investigated. The extraction behavior of these metals from the bottom phase (BP) to the upper phase (UP) of the ATPS is affected by the amount of added extractant (potassium iodide), tie-line length (TLL), mass ratio between the phases of the ATPS, leaching and dilution factor of the battery samples. Maximum extraction of Cd (99.2 ± 3.1)% and Ni (10.6 ± 0.4)% is obtained when the batteries are leached with HCl, under the following conditions: 62.53% (w/w) TLL, concentration of KI equal to 50.00 mmol kg −1 , mass ratio of the phases equal to 0.5 and a dilution factor of battery samples of 35. This novel methodology is efficient to separate the metals in question, with the advantage of being environmentally safe, since water is the main constituent of the ATPS, which is prepared with recyclable and biodegradable compounds.