Saccharides In Aqueous Solutions Research Articles

Фізико-хімічні та біологічні властивості сахаридів та спирту після радіаційної обробки

The results of a complex study of the influence of nuclear radiation on the physical and chemical properties of distilled water, aqueous solutions of saccharides, ethyl alcohol, and their biological activity are presented. Irradiation was carried out on the M-30 microtron electron accelerator (12.5 MeV) and on isotope radiation stands based on 241Am, 137Cs, and 240Pu, which generate mixed nuclear radiation. The temporal evolution of chemical indicators and optical and frequency characteristics of electrical parameters of irradiated water environments are discussed. The selective biological effect of irradiated compounds on test microorganisms from different phylogenetic groups was established.

Interaction of Organogermanium Compounds with Saccharides in Aqueous Solutions: Promotion of Aldose-to-ketose Isomerization and Its Molecular Mechanism.

This review discusses sugar isomerization with organogermanium compounds. Organogermanium compounds markedly increase the aldose-ketose (glucose-fructose or lactose-lactulose) isomerization ratio, double the initial reaction rate, and significantly reduce the base-catalyzed degradation of sugars. 1H-nuclear magnetic resonance analysis reveals that the affinity of organogermanium compounds with a 3-(trihydroxygermyl)propanoic acid (THGP) structure toward ketoses is 20-40 times stronger than that toward aldoses; thus, such organogermanium compounds form complexes more readily with ketoses than with aldoses. Stable ketose complexes, which contain multiple cis-diol structures and high fractions of furanose structures, suppress the reverse ketose-aldose reaction, thereby shifting the equilibrium toward the ketose side. These complexes also protect sugar molecules from alkaline degradation owing to the repulsion between anionic charges. The increased rate of the initial reaction in the alkaline isomerization process results from stabilizing the transition state by forming a complex between THGP and a cis-enediol intermediate. The cyclic pentacoordinate or hexacoordinate THGP structures give rise to a conjugated system of germanium orbitals, which is extended through dπ-pπ interactions, thereby improving the stability of the complex. Based on these results, we have developed a bench-scale lactulose syrup manufacturing plant incorporating a system to separate, recover, and reuse organogermanium poly-trans-[(2-carboxyethyl)germasesquioxane]. This manufacturing plant can be used as a model of an alkaline isomerization accelerator for continuous industrial production.

Polysaccharides from Moroccan Green and Brown Seaweed and Their Derivatives Stimulate Natural Defenses in Olive Tree Leaves

This study aims to assess for the first time the ability of marine polysaccharides and their derivatives to stimulate natural defenses in olive tree leaves. Alginates, ALSM, and ALCM were isolated from the brown algae Sargassum muticum and Cystoseira myriophylloides, respectively. The OASM and OACM fractions were obtained after radical depolymerization of ALSM and ALCM, respectively. Three sulfated polysaccharides, arabinogalactans (AGB and AGP) and fucoidans (FUCCM) were extracted from the green alga Codium decorticatum and the brown seaweed C. myriophylloides, respectively. The extraction yield of different extracts was in the range of 0.82–32% and the average molecular weight (Mw) varied from 3000 Da to 2173 kDa. The M/G ratios of ALSM and ALCM were 0.87 and 1.12, respectively. FUCCM contained 53% of fucose and 12.83% of sulfates. The AGB and AGP fractions were characterized by the presence of a high degree of sulfation and protein (12–23% (w/w)) and were composed mainly of galactose, glucose, and arabinose. The aqueous saccharide solutions were applied to the leaf discs of the olive tree at 0.5 g/L, 1 g/L, and 2 g/L, for 24 h. These molecules triggered defense responses, by showing a differential capacity to induce the activity of the phenylalanine and tyrosine ammonia-lyase (TAL and PAL), polyphenols, and lignin contents in the leaves of the olive tree. Alginates and their derivatives as well as arabinogalactans exhibited an important induction of TAL activity compared to the PAL. The sulfated polysaccharides were more effective compared to the unsulfated polysaccharides (alginates) which were active at a low concentration. The optimum concentration for most of the studied elicitors was 2 g/L. These results suggest the valorization of these molecules derived from marine biomass as inducers of natural defenses of the olive tree to protect against phytopathogens in the context of sustainable development.

Efficiently Computing NMR 1H and 13C Chemical Shifts of Saccharides in Aqueous Environment.

Determining the structure of saccharides in their native environment is crucial to understanding their function and more accurately targeting their utilization. Nuclear magnetic resonance observables such as the nuclear Overhauser effect or spin-spin coupling constants are routinely utilized to study saccharides in their native water environment. However, while highly sensitive to the local environment, chemical shifts are mostly overlooked, despite being commonly measured for compounds identification. Although chemical shifts carry considerable structural information, their direct association with structure is notoriously difficult. This is mostly due to the similarity in the chemical nature of most saccharides causing similar physicochemical environments close to sugar C and H atoms, resulting in comparable chemical shifts. The rise of computational power allows one to compute reliable chemical shifts and use them to determine atomistic details of these sugars in solution. However, any prediction is severely limited by the computational protocol used and its accuracy. In this work, we studied a set of 31 saccharides on which we evaluated various computational protocols to calculate the total number of 375 1H and 327 13C chemical shifts of sugars in an aqueous environment. Our study proposes two cost-effective protocols for simulating 1H and 13C chemical shifts that we recommend for further use. These protocols can help with the interpretation of experimental spectra, but we also show that they are also capable of structure prediction independently. This is possible because of the low mean absolute deviations of calculated shifts from the experiment (0.06 ppm for 1H and 1.09 ppm for 13C). We explore different solvation methods, basis sets, and optimization schemes to reach such accuracy. A correct sampling of the conformation phase space of flexible sugar molecules is also key to obtaining accurately converged theoretical chemical shifts. The linear regression method was applied to convert the calculated isotropic nuclear magnetic shielding constants to simulated chemical shifts comparable with the experiment. The achieved level of accuracy can help in utilizing chemical shifts for elucidating the 3D atomistic structure of saccharides in aqueous solutions. All linear regression parameters obtained on our extensive set of sugars for all the tested protocols can be reutilized in future works.

Study of interactions of the cationic 12–2–12 Gemini surfactant with saccharides in aqueous solution: volumetric, compressibility and viscometric analysis

Abstract In the present study, the interaction behaviour of 12–2–12 Gemini surfactant in aqueous saccharide solutions (lactose and maltodextrin solutions) is investigated using density, sound velocity and viscosity measurements. The density and sound velocity data were used to determine the volume and compressibility parameters. The effects of temperature and concentration/strength of the solutions on the interaction behaviour were analysed by conductivity studies over a wide temperature (293.15–313.15) K and concentration range of the saccharides as well as of the surfactant. It was found that predominantly hydrophobic interactions together with ionic/hydrophilic interactions between 12–2–12 Gemini surfactant and the saccharides maltodextrin and lactose play a role. In addition, the structural changes in the 12–2–12 Gemini solutions induced by lactose and maltodextrin were investigated by viscosity measurements. The results confirm the observations from the volume and compressibility studies. The study of the different hydrophobic/hydrophilic interactions in the Gemini surfactant-sacharide-water mixtures are very helpful to understand the structural behaviour of Gemini surfactants in the view of their biological significance.

Computational quantitation of the aldehyde forms of aldohexoses and disaccharides composed of d-glucose: Predictions of their reactivities in the Maillard reaction

The aldehyde forms of saccharides are the major reactants in the Maillard reaction of sugars with the free amine groups of proteins. The ratios of the aldehyde forms of saccharides in aqueous solutions are crucial to rate determining of the Maillard reaction. The aldehyde ratios of disaccharides and oligosaccharides have been barely analyzed experimentally or computationally. Here, we tested the feasibility of the quantum chemical calculation with various calculation levels and aqueous solution models to predict the aldehyde ratios of disaccharides comprising d-glucose. The aldehyde ratio of the d-glucose calculated employing the CAM-B3LYP/6–311+G(2d,2p) level of theory and the solute electron density (SMD) solvent model closely consisted with the experimental data. Additionally, the aldehyde ratios of disaccharides correlated with the oxime formation tendency investigated with Nα-(aminooxyacetyl)tryptophanylarginine amide. This prediction method could be applied to the quantitation of the aldehyde forms of oligosaccharides, as well as the design of saccharide-based drugs.

Use of Raman and Raman optical activity to extract atomistic details of saccharides in aqueous solution.

Sugars are crucial components in biosystems and industrial applications. In aqueous environments, the natural state of short saccharides or charged glycosaminoglycans is floating and wiggling in solution. Therefore, tools to characterize their structure in a native aqueous environment are crucial but not always available. Here, we show that a combination of Raman/ROA and, on occasions, NMR experiments with Molecular Dynamics (MD) and Quantum Mechanics (QM) is a viable method to gain insights into structural features of sugars in solutions. Combining these methods provides information about accessible ring puckering conformers and their proportions. It also provides information about the conformation of the linkage between the sugar monomers, i.e., glycosidic bonds, allowing for identifying significantly accessible conformers and their relative abundance. For mixtures of sugar moieties, this method enables the deconvolution of the Raman/ROA spectra to find the actual amounts of its molecular constituents, serving as an effective analytical technique. For example, it allows calculating anomeric ratios for reducing sugars and analyzing more complex sugar mixtures to elucidate their real content. Altogether, we show that combining Raman/ROA spectroscopies with simulations is a versatile method applicable to saccharides. It allows for accessing many features with precision comparable to other methods routinely used for this task, making it a viable alternative. Furthermore, we prove that the proposed technique can scale up by studying the complicated raffinose trisaccharide, and therefore, we expect its wide adoption to characterize sugar structural features in solution.

Use of Raman and Raman optical activity to extract atomistic details of saccharides in aqueous solution

Use of Raman and Raman optical activity to extract atomistic details of saccharides in aqueous solution

Surface Properties and Morphology of Boron Carbide Nanopowders Obtained by Lyophilization of Saccharide Precursors.

The powders of boron carbide are usually synthesized by the carbothermal reduction of boron oxide. As an alternative to high-temperature reactions, the development of the carbothermal reduction of organic precursors to produce B4C is receiving considerable interest. The aim of this work was to compare two methods of preparing different saccharide precursors mixed with boric acid with a molar ratio of boron to carbon of 1:9 for the synthesis of B4C. In the first method, aqueous solutions of saccharides and boric acid were dried overnight at 90 °C and pyrolyzed at 850 °C for 1 h under argon flow. In the second method, aqueous solutions of different saccharides and boric acid were freeze-dried and prepared in the same way as in the first method. Precursors from both methods were heat-treated at temperatures of 1300 to 1700 °C. The amount of boron carbide in the powders depends on the saccharides, the temperature of synthesis, and the method of precursor preparation.

Dielectric relaxation and molecular interactions study of saccharides in aqueous solutions

Time domain reflectometry (TDR) technique has been extensively used to study dielectric relaxation and solution properties of carbohydrates. Using TDR techninque, complex permittivity spectra of monosaccharides (d-fructose and d-xylose) and disaccharides (d-maltose monohydrates) were obtained in the frequency range of 10 MHz–50 GHz at various concentrations and temperatures. The static dielectric constant (ε0), dielectric constant at high frequency (ε∞), relaxation time (τ) and relaxation time distribution parameter (β) extracted from the complex permittivity spectra using least squares fit method. The values of static dielectric constant were also verified by LCR meter by dielectric measurement in the frequency range of 20Hz to 2 MHz at 25 °C. The relaxation behavior of aqueous solutions of monosaccharides and disaccharides has been illustrated by using Cole-Davidson model. Activation enthalpy (ΔH), entropy (ΔS) and Kirkwood correlation factor have been determined to study extent of hydrogen bonding. This data might be useful in pharmaceutical, food processing industry and in solubility prediction method in aqueous solution.

Effect of Spacer Length in Pyrene-Modified-Phenylboronic Acid Probe/CyD Complexes on Fluorescence-based Recognition of Monosaccharides in Aqueous Solution.

The chemical sensing of saccharides is of importance for the diagnosis of diabetes. Various enzymatic sensors have been developed, but their heat and pH instability issues need to be resolved. In this regard, the development of artificial saccharide sensors with high stability is attracting attention. We have designed a heat- and pH-stable supramolecular inclusion complex system composed of cyclodextrin (CyD) as a host and a phenylboronic acid (PB) probe possessing pyrene as a fluorescent guest. Several probes possessing alkyl spacers having various lengths between the PB and the pyrene moiety, Cn-APB (n = 1 - 4), were newly synthesized and evaluated with respect to their monosaccharide recognition ability on the basis of the fluorescence response through the cyclic esterification of monosaccharide and PB. These Cn-APB/CyD supramolecular inclusion complexes have exhibited a selective fluorescence response towards fructose in aqueous solution based on the photo-induced electron transfer mechanism. The spacer length of the alkyl group in Cn-APB significantly affects the affinity for saccharides. With respect to the complex between C4-APB and PB-modified CyD (3-PB-γ-CyD), it was found that the supramolecular inclusion complexes had high selectivity for glucose with significant fluorescence enhancement. These results indicate that the lengths of the alkyl spacers in the probe molecules are important to control the recognition of saccharides in aqueous solution.

Quantitative assessment of the interactions between the organogermanium compound and saccharides using an NMR reporter molecule

Poly-trans-[(2-carboxyethyl)germasesquioxane], Ge-132, is a water-soluble organogermanium compound reported to have physiological effects such as immunostimulatory and antiviral effects. The hydrolysate of Ge-132, 3-(trihydroxygermyl)propanoic acid (THGP), can interact with diols; therefore, it likely can interact with diol-containing sugars in sugar chains, glycoproteins, and glycolipids, which have important physiological functions. In this study, we quantitatively assessed the ability of THGP to interact with saccharides using nuclear magnetic resonance (NMR) spectroscopy and THGP derivatives. THGP was complexed by binding its trihydroxy group with saccharides in aqueous solutions via the cis-diol group rather than the trans-diol group. The spectra of THGP and monosaccharides indicated that THGP has a higher affinity for ketose than aldose. Moreover, the complexation ability between THGP and saccharides was influenced by the number of cis-diol groups on the saccharide structure. Thus, interactions of THGP with important biological sugars might be involved in the physiological functions of Ge-132.

New insights into the mechanism of photocatalytic hydrogen evolution from aqueous solutions of saccharides over CdS-based photocatalysts under visible light

A new multiphase photocatalyst – 1%Pt/Cd0.6Zn0.4S/Cd0.1Zn0.9S – was synthesized by a simple hydrothermal treatment of as-prepared Cd0.3Zn0.7S solid solution and thoroughly characterized by different methods. The activity was tested in a sustainable process of hydrogen evolution from aqueous solutions of two saccharides (glucose and xylose) under visible light. The mechanism of the photocatalytic hydrogen evolution from complex organic substrates is still controversial. In this research it was shown that optimizing the experimental conditions (pH, substrate concentration) leads to a significant increase in the photocatalytic activity for both saccharides. A kinetic equation based on a Langmuir model and including the degree of dissociation of the substrate was proposed and verified for the first time. The highest activities during hydrogen evolution for glucose and xylose were achieved in strongly alkaline media. The photocatalyst 1%Pt/CdZnS120 possessed an activity equal to 3.4 mmol H2 h−1 g−1 (glucose, apparent quantum efficiency 8.4%), that exceeds recently reported values.

The sweetness response and thermophysical properties of glucose and fructose in the aqueous solution of some deep eutectic solvents at T= (288.15–318.15) K

Thermophysical properties elucidate the sweetness response, taste quality and hydration characteristics of saccharides in the aqueous solutions and offer significant information for pharmaceutical and food industries. In this current work, the effect of some neoteric green solvents as named deep eutectic solvents (DESs) on the sweetness response, taste quality and hydration behavior of the glucose and fructose solutions have been investigated from apparent specific volumes ASV, apparent specific isentropic compressibility ASIC parameters. The standard partial molar volumes Vφ0, transfer apparent molar volumes ΔtrVφ0, partial molar isentropic compressibilities Kφ0, viscosity B-coefficients and molar refractions RD the aqueous solutions of saccharides in choline chloride (ChCl)-urea, ChCl-ethylene glycol (EG), dimethyl ammonium chloride (DMAC)-ethylene glycol as DESs have been calculated from measured density, speed of sound, viscosity and refractive index data at T= (288.15–318.15) K. The results indicated that glucose in the aqueous solutions of ChCl-urea has the strongest interactions and get stronger with increasing the concentration of DES and temperature. Interaction volume Vint and cavity volume Vcav have been computed from scaled particle theory (SPT).

Apparent molar volume, isentropic compressibilities, viscosity B-coefficients and activation parameters of thiamine hydrochloride in aqueous solutions of saccharides at different temperatures

In this paper, volumetric, ultrasonic and viscometric analysis of thiamine hydrochloride in aqueous and mixed aqueous solutions of saccharides such as (0.1 mol kg−1 D-(-)-fructose, 0.1 mol kg−1 D-(+)-maltose and 0.1 mol kg−1 sucrose) over the temperature range (293.15–318.15) K and pressure, p = 101.3 kPa have been carried out. These have assisted in understanding the solute–solute, solute–solvent and solute–solvent interactions prevailing in the considered system. From the density data, the parameters like the apparent molar volume (Vϕ), limiting apparent molar volume (V0ϕ) and limiting apparent molar volume of transfer (ΔtrV0ϕ) have been computed. From the ultrasonic studies, the apparent molar isentropic compression (Kϕ,s), limiting apparent molar isentropic compression(K0ϕ,s) and limiting apparent molar isentropic compression of transfer (ΔtrK0ϕ,s) have been assessed. The Kϕ,s values are negative and that of ΔtrK0ϕ,s values are positive for thiamine hydrochloride in mixed aqueous 0.1 mol kg−1 systems of fructose/maltose/sucrose. From viscosity data, Falkenhagen A-coefficients and viscosity B-coefficients have been evaluated by employing the Jones-Dole equation. The Hepler’s constant (∂2V0ϕ/∂T2), limiting apparent molar expansibility (E0ϕ), thermal expansion coefficient (α), solvation number (Sn), activation parameters related to viscous flow (Δμ01, Δμ02, TΔS02 and ΔH02) etc. have also been estimated. By examining these results, we procured that the thiamine hydrochloride behaves as a structure breaker in aqueous and mixed aqueous solutions of saccharides.

The effect of saccharides on equilibrium swelling of thermo-responsive gels.

Mechanical and optical properties of thermo-responsive (TR) gels change drastically at their volume phase transition temperature. As the critical temperature is strongly affected by the presence of small amounts of additives in aqueous solutions, TR gels can be employed as sensors for detection and recognition of multiple analytes (from specific ions to hazardous biochemicals to pathogenic proteins) and actuators for biomedical applications. A simplified mean-field model is developed for equilibrium swelling of TR gels in aqueous solutions of additives. Its advantage is that the model involves a relatively small (compared with the conventional approaches) number of material constants and accounts for changes in the thermo-mechanical response at transition from the swollen to collapsed state. The ability of the model to describe experimental swelling diagrams and to predict the influence of additives on the equilibrium degree of swelling and the volume phase transition temperature of TR gels is confirmed by comparison of observations on poly(N-isopropylacrylamide) gel in aqueous solutions of saccharides (glucose, sucrose and galactose) with results of numerical analysis.

Investigation of the solute-solute and solute-solvent interactions in ternary {saccharide + ionic liquid + water} systems

The aim of this work is to investigate the salt effect resulted by addition of ionic liquids to aqueous saccharide solutions. To achieve this goal, systematic studies have been made on ternary {saccharide+ionic liquid+water} system using the available vapor-liquid equilibrium (VLE) data published recently. Vapor pressure depression, osmotic and activity coefficient data for the ionic liquids and saccharides in the binary solutions are used to investigate ionic liquid-water and saccharide–water interactions. For ternary solutions, the calculated activity coefficient of saccharides in presence of ionic liquids, transfer Gibbs energies, pair and triplet interaction parameters and salting constants are used to investigate saccharide-ionic liquid interactions. The variety of ionic liquids based on imidazolium and pyridinium have been considered. To extent the number of systems considered in this work, we have also included vapor-liquid equilibrium studies on the new systems {d-fructose+1-butyl-4-methyl pyridinium bromide+H2O} and {sucrose+1-butyl-4-methyl pyridinium bromide+H2O} from which experimental water activity data are measured. The aforementioned properties were also calculated for these new systems. In this article, the effect of stereochemistry of sugar, cation (imidazolium or pyridinium), chain length and anion of ionic liquids on vapor-liquid equilibrium behavior of these ternary systems and saccharide-ionic liquid interactions have been discussed. Generally, we found that there is a relationship between soluting-in or soluting-out behavior of ionic liquids and their hydration so that soluting-in effect is observed in ionic liquids with longer chain length and with anions having smaller values of osmotic coefficient. Soluting-out effect is observed in ionic liquids with shorter chain length and with anions having larger values of osmotic coefficient. From the VLE results we conclude that soluting-out effect of ionic liquids also depends on the hydration of saccharides and is observed in saccharides with high tendency to interact with water.

Discrimination of Saccharides by a Simple Array.

We report the development of a two-component probe system as fluorescence turn-on assay of simple saccharides. The quenching of an anionic conjugated water-soluble polymer by a cationic quencher has been reported previously. Three different boronic acid functionalized benzyl viologens and three conjugated polymers of the poly(aryleneethynylene) type form nine non-fluorescent complexes. This small library discriminates nine different simple saccharides in aqueous solutions by fluorescence turn-on in a displacement assay. The saccharides can be discriminated and identified with this simple system.

Mid-infrared spectroscopic analysis of saccharides in aqueous solutions with sodium chloride.

The infrared spectral characteristics of three different types of disaccharides (trehalose, maltose, and sucrose) and four different types of monosaccharides (glucose, mannose, galactose, and fructose) in aqueous solutions with sodium chloride (NaCl) were determined. The infrared spectra were obtained using the FT-IR/ATR method and the absorption intensities respected the interaction between the saccharide and water with NaCl were determined. This study also focused on not only the glycosidic linkage position and the constituent monosaccharides, but also the concentration of the saccharides and NaCl and found that they have a significant influence on the infrared spectroscopic characterization of the disaccharides in an aqueous solution with NaCl. The absorption intensities representing the interaction between a saccharide and water with NaCl were spectroscopically determined. Additionally, the applications of MIR spectroscopy to obtain information about saccharide-NaCl interactions in foods and biosystems were suggested.

Viscosities of Some Saccharides in Aqueous Solutions of Phosphate-Based Inorganic Salts

The viscosities η of some monosaccharides, their methyl- and deoxy- derivatives, disaccharides, and trisaccharides have been measured in (0.25, 0.5, 1.0, and 1.25) mol·kg–1 aqueous solutions of potassium phosphate (KH2PO4) and (0.5, 1.0, 1.5, and 2.0) mol·kg–1 aqueous solutions of sodium phosphate (NaH2PO4) and ammonium phosphate (NH4H2PO4) monobasic salts, and potassium phosphate (K3PO4) tribasic salt over the temperature range (288.15 to 318.15) K and at atmospheric pressure, P = 0.1 MPa. The viscosity data have been utilized to calculate the Jones–Dole viscosity B-coefficients and their corresponding coefficients of transfer, ΔtB. The ΔtB values were found to be positive and their magnitudes vary depending on the nature of solutes and cosolutes. The dB/dT coefficients and pair ηAB and triplet ηABB interaction coefficients have also been calculated and discussed in terms of solute–solvent/cosolute interactions. The results have been compared in phosphate-based salts on the basis of the nature of the cat...