Water Ternary Solutions Research Articles

Process optimization for dehydration of shelled peas by osmosis and three‐stage convective drying for enhanced quality

Peas are highly seasonal and perishable in nature, thereby requiring suitable preservation methods to be available throughout the year. Osmotic drying is one of the suitable methods for preserving perishable and semi-perishable produce. Osmotic drying of green peas was carried out in ternary solutions of water, sodium chloride (NaCl), and sucrose having different solution concentrations and osmotic temperatures. Three-stage drying of osmotically pretreated green peas was carried out in convective tray dryer at air temperatures of 70°C (for first 3 hr), 60°C (for next 2 hr), and 50°C (till final moisture content of below 10% wb). The samples were analyzed for moisture content, color change, sphericity, hardness, and rehydration ratio (RR). The osmotic drying process was optimized using response surface methodology (RSM). The optimized process conditions for maximum sphericity, hardness, and RR and for minimum moisture content and color change were determined as sodium chloride solution (10% w/w) and osmotic temperature of 34.41°C. Practical applications Osmotic drying of foods is advantageous when used in combination with other drying techniques as it reduces total drying time, inhibits enzymatic browning, and also reduces energy costs. This study would help to understand the effect of osmotic solution concentration and osmotic temperature on quality of osmo-convective dried peas. Optimization of process parameters would provide the best combination of osmotic solution concentration and osmotic temperature for achieving better product quality in terms of moisture content, color, hardness, rehydration ratio, and sphericity. The high-quality product hence obtained using optimized process parameters will find utilization not only in soup mixes, ready-to-eat snack foods but also as fresh-like peas upon rehydration during off-seasons.

Development of <i>α</i>-Amino Acid Detection with Peroxyoxalate Chemiluminescence by Using Water-Acetonitrile-Ethyl Acetate Mixed Solution

Peroxyoxalate chemiluminescence was, for the first time, examined by using ternary mixed solutions of water-hydrophilic/hydrophobic organic solvent. Eosin Y as a model fluorescence compound was dissolved with the ternary solutions of water (1.0 mM carbonate buffer, pH 9.0)-acetonitrile-ethyl acetate, water-rich of 15:3:2 volume ratio and organic solvent-rich of 3:8:4 volume ratio, to which bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide chemiluminescence reagent were added. The chemiluminescence observed with the ternary solutions, especially the organic solvent-rich solution, showed a larger signal than that observed with the water only solution or water-acetonitrile mixed solution. Chemiluminescence in the presence of twenty types of α-amino acid was similarly examined by using the ternary organic solvent-rich solution. The chemiluminescence of three α-amino acids with fluorescence properties was enhanced with the ternary solution. The data reported here may contribute to development of a new, sensitive peroxyoxalate chemiluminescence detection system.

Phase behaviour and non-monotonic film drying kinetics of aluminium chlorohydrate–glycerol–water ternary solutions

We study the drying and film formation of a model ternary system comprising an inorganic salt (aluminium chlorohydrate, ACH), a humectant (glycerol) and water. Employing viscometric, X-ray diffraction, calorimetric, dynamic vapour sorption, spectroscopic, gravimetric and adhesion measurements, we examine the roles of humectant concentration, temperature and relative humidity (RH) in the phase behaviour and kinetics of film formation. Equilibrium film compositions are found to be non-monotonic with glycerol content. Around 15:4 ACH:glycerol mass ratio, films exhibit enhanced, albeit slower, desiccation, with water content lower than that of binary ACH–water solutions. At higher glycerol content, drying is faster, yet the resulting films have higher water content and remain tackier. Water adsorption/desorption is shown to be fully reversible, and share a similar non-monotonic kinetic dependence on glycerol composition. These findings are rationalised in terms of the competitive binding of water and glycerol to ACH, the overall miscibility and glass formation within the ternary system. Our study is relevant to a range of salt formulations, employed in a variety of commercial applications, including lyoprotectants and personal care products.

Volumetric and acoustic studies of l-tyrosine+l-glutamic acid+water at different temperatures

Abstract The speeds of sound and densities of different concentrations of l -tyrosine + l -glutamic acid + water ternary solutions, l -tyrosine + water and l -glutamic acid + water binary solutions at T = (298.15, 308.15, 318.15) K have been measured. Using the densities and the speeds of sound, the apparent molar volumes, the apparent molar isentropic compressibilities, the limiting apparent molar volume, the limiting apparent molar compressibility, the constants ( S V , S , S V , K , S K , S and S K , E ) and the hydration number have been calculated. These parameters have been used to analyze the possible interionic interactions, such as ion–ion, solute–solvent, solvent–solvent, ion–solvent, and solute-co-solute interactions, and are discussed in terms of hydrophobic–hydrophobic, and hydrophilic–hydrophobic group interactions as well as, structure-making and structure-breaking effects in l -tyrosine + l -glutamic acid + water.

Densities and Viscosities of Erythritol, Xylitol, and Mannitol in l-ascorbic Acid Aqueous Solutions at T = (293.15 to 323.15) K

The densities and viscosities of ternary solutions (erythritol/xylitol/mannitol + l-ascorbic acid + water) and binary solutions (erythritol/xylitol/mannitol + water), were measured under atmospheric pressure and the temperature range of (293.15 to 323.15) K. The apparent molar volumes (Vφ), the limiting partial molar volumes (Vφ0) and the limiting partial molar volumes of transfer (ΔtrVφ0) were calculated through densities, respectively. Guimarães equation and extended Jones-Dole equation were applied to correlate the densities and viscosities of erythritol/xylitol/mannitol in l-ascorbic acid aqueous solutions, respectively. The free energy of activation per mole of solvent (Δμ10≠) and solute (Δμ20≠) were obtained through the viscosity B-coefficients. These significant parameters are helpful to understand the interactions in sugar alcohols + l-ascorbic acid + water ternary solutions.

Density and viscosity of sorbitol/maltitol in l-ascorbic acid aqueous solutions at T = (293.15 to 323.15) K

Densities, ρ, and viscosities, η, of ternary solutions (sorbitol/maltitol+l-ascorbic acid+water) and binary solutions (sorbitol/maltitol+water) were measured at T=(293.15 to 323.15)K under atmospheric pressure. Guimarães equation and extended Jones–Dole equation were applied to correlate the densities and viscosities of the solutions, respectively. The apparent molar volume (Vφ), limiting partial molar volume (Vφ0) and limiting partial molar volume of transfer (ΔtrVφ0) were calculated by densities. The free energy of activation per mole of solvent (Δμ10≠) and free energy of activation per mole of solute (Δμ20≠) were calculated through the obtained viscosity B-coefficients, respectively. These significant parameters are helpful to understand the interactions in sugar alcohols+l-ascorbic acid+water ternary solutions and also to study the substance conversion and transfer in living liquid system.

Calculation of the Density and Activity of Water in ATPS Systems for Separation of Biomolecules

In this study, the perturbed hard sphere chain equation of state is utilized to calculate the activity of water in binary and ternary solutions of polyethylene glycol (PEG), salt and water. The liquid density of the binary and ternary solutions is also predicted. To estimate the water activity in PEG–water binary systems, a linear correlation is obtained for the binary interaction parameter between water and PEG. Then, using this correlation and without introducing any additional binary parameters, the water activities are predicted in ternary solutions of water, salt and PEG with different molecular weights (MW). Our results show that the mean absolute average relative deviation (AARD %) of water activity for binary PEG–water solutions in 298 K is 0.73 %. In addition, the water activity in ternary solutions of water and two PEGs with different MW is predicted within 0.31 % AARD %. Furthermore, the AARD % for prediction of water activities in binary PEG–water solutions over the temperature range 308–338 K is 0.41 %. Also, the water activities of aqueous two-phase systems are predicted with AARD % = 0.64 %. In this regard, no adjustable parameters were correlated between salt and PEG. Finally, liquid densities were predicted in binary solutions of water–PEG and ternary solutions of water–PEG–salt.

Chemical treatment of commercial reverse osmosis membranes for use in FO

Commercially available reverse osmosis (RO) membranes – SW30HR, BW30, and AG – were chemically treated for use in forward osmosis (FO). Nitric acid, phosphoric acid, sulfuric acid, ethanol, and ethanol–acid–water ternary solutions were employed for the treatment. All three membranes, after treatment by nitric acid, ethanol, and ethanol–acid–water solutions, demonstrated significant flux enhancement (as much as 40 times higher) compared to their untreated counterparts. The SW30HR membrane treated by ethanol showed the lowest reverse salt flux among the treated membranes. Extensive changes to the barrier layer of the SW30HR membrane after ethanol treatment were observed using ATR-FTIR, XPS, and contact angle measurements. It appears that the PVA coating of the SW30HR membrane was either partially or totally removed. The reduction/removal of the PVA layer in conjunction with higher wettability of the substrate induced by ethanol treatment appears responsible for the improved flux.

Polyion–counterion interactions in sodium carboxymethylcellulose–ethylene glycol–water ternary solutions

Polyion–counterion interactions in sodium carboxymethylcellulose–ethylene glycol–water ternary system have been investigated with special reference to their variations with the polyelectrolyte concentration, the medium relative permittivity and the temperature using electrical conductance measurements. The experimental data have been analyzed on the basis of a model for semidilute polyelectrolyte conductivity which takes into account the scaling arguments proposed by Dobrynin et al. Concentration-dependent moderate counterion condensation (24–33%) was observed. Counterion condensation is found to be spontaneous which depends upon the EG-content of the medium and the temperature. A major proportion of the current is transported by the carboxymethylcellulose polyions. The results further demonstrated that the monomer units experience more frictional resistance in solution as the EG-content increases or as the temperature decreases.

Structure-making tendency of ionic liquids in the aqueous d-glucose solutions

Densities (d) of d-glucose+ionic liquid {1-pentyl-3-methylimidazolium bromide ([PnMIm]Br) and 1-hexyl-3-methylimidazolium bromide ([HMIm]Br)}+water ternary solutions were measured at T=288.15, 298.15, 308.15 and 318.15K as a function of d-glucose molality in 0.2, 0.3, 0.4 and 0.5molkg−1 of ionic liquids. The measured density values were used to calculate the standard partial molar volume (Vϕ0), partial molar expansivity (Eϕ0), hydration number (nH) and volumetric interaction coefficients (VSIL and VSILIL) at different temperatures. These parameters have been discussed in terms of solute–solvent interactions and structure making/breaking abilities of d-glucose and ionic liquids. It is also attempted to understand the effects of cation size of ionic liquid and temperature on the volumetric properties. The results show that the longer alkyl chain of ionic liquid has the stronger interactions with d-glucose and this type of interactions is further increased at high temperatures.

Trehalose Bioprotective Effects in Lysozyme Aqueous Solution Studied by Brillouin Scattering and Calorimetric Measurements

The bioprotective effect of trehalose in lysozyme aqueous solutions has been investigated by Brillouin scattering and modulated-temperature differential scanning calorimetry (MDSC). MDSC experiments show that the isothermal kinetics of thermally irreversible denaturation can be described by the Arrhenius equation. By the addition of trehalose, the irreversible denaturation of lysozyme is suppressed, and its activation energy is half that of the denaturation without trehalose. The sound velocity of lysozyme–trehalose–water ternary solutions obviously depends on the trehalose concentration. With increasing trehalose concentration, the sound velocity becomes higher because the hydration of trehalose reduces the hydrogen bonds between water molecules. Moreover, hydration around lysozyme molecules increases the sound velocity further. Trehalose molecules tend to aggregate with lysozyme molecules at high trehalose concentrations. The bioprotective effect of trehalose probably originates from the mechanical suppression of conformational fluctuations of lysozyme molecules.

Critical Crossover Phenomena in Ternary Solutions of Water+3-methylpyridine+Sodium Bromide

采用折射率法在较宽温度范围内研究了溴化钠、3-甲基吡啶和水的临界质量分数分别为0．240、0．192和0．568体系的临界性质，发现在近临界点临界指数为0．365，与Fisher重整化值一致．有效临界指数随着温度逐渐远离临界点，从0．365下降到0．20左右，但当排除了“正规项”的影响后，展现出向平均场理论值0．5单调跨接的行为．

Effect of co-solvent complex on preferential adsorption phenomenon in polyvinyl alcohol ternary solutions

In this work, the effect of co-solvent complex on preferential adsorption phenomenon in polyvinyl alcohol (PVA)/N-methyl-2-pyrrolidone (NMP)/water ternary solutions was studied. It should be noticed that in this system one NMP molecule could bind with two water molecules to form NMP(water)2 ter-solvency complex. The formation of the NMP(water)2 complex is found to significantly affect the preferential adsorption phenomenon. At the NMP volume fraction of φ1<0.73 in co-solvent mixture, the PVA chains preferentially adsorb the water molecule. Owing to the poorer affinity of water compared with that of NMP to PVA, contracted PVA coils are formed at this condition. At φ1>0.73, the PVA chains preferentially adsorb the NMP molecule, which is a better solvent for PVA, inducing an A2 value that rapidly increases. The PVA coil exhibits a much-extended conformation. Moreover, the theoretical values of preferential adsorption coefficient, αa, obtained from two Read formalisms are in poor agreement with the experimental results. This is due, considerably, to the effect of the NMP(water)2 complex formation in this co-solvent system.