Polysaccharide Solutions Research Articles

Activation of Soluble Polysaccharides with 1-Cyano-4-Dimethylaminopyridine Tetrafluoroborate (CDAP) for Use in Protein-Polysaccharide Conjugate Vaccines and Immunological Reagents. III Optimization of CDAP Activation.

CDAP (1-cyano-4-dimethylaminopyridine tetrafluoroborate) is employed in the synthesis of conjugate vaccines as a cyanylating reagent. In the published method, which used pH 9 activation at 20 °C (Vaccine, 14:190, 1996), the rapid reaction made the process difficult to control. Here, we describe optimizing CDAP activation using dextran as a model polysaccharide. CDAP stability and reactivity were determined as a function of time, pH and temperature. While the rate of dextran activation was slower at lower pH and temperature, it was balanced by the increased stability of CDAP, which left more reagent available for reaction. Whereas maximal activation took less than 2.5 min at pH 9 and 20 °C, it took 10–15 min at 0 °C. At pH 7 and 0 °C, the optimal time increased to >3 h to achieve a high level of activation. Many buffers interfered with CDAP activation, but DMAP could be used to preadjust the pH of polysaccharide solutions so that the pH only needed to be maintained. We found that the stability of the activated dextran was relatively independent of pH over the range of pH 1–9, with the level of activation decreased by 40–60% over 2 h. The use of low temperature and a less basic pH, with an optimum reaction time, requires less CDAP, improving activation levels while making the process more reliable and easier to scale up.

ЕФЕКТИВНІСТЬ ПОПЕРЕДНЬОГО ОБРОБЛЕННЯ ЯГІД СУНИЦІ РОЗЧИНОМ ХІТОЗАНУ ЗА ХОЛОДИЛЬНОГО ЗБЕРІГАННЯ В МОДИФІКОВАНОМУ ГАЗОВОМУ СЕРЕДОВИЩІ

Strawberries (Fragaria ananassa) belong to short-term berries. Many technologies are used to extend its shelf life. One of the current technologies is the use of pretreatment of berries with polysaccharide solutions before refrigerated storage. This treatment makes it possible to reduce weight loss and improve the overall quality of berries by forming a protective barrier film on their surface. The purpose of this study was to investigate the effectiveness of chitosan strawberries pre-treatment while storing it in a refrigerated chamber using a modified gas atmosphere. To achieve the purpose, strawberries were treated with 0,05 %; 0,2 %; 0,5 % aqueous solutions of low molecular weight chitosan were stored in a refrigerator at t 0 + 2 °C using polyethylene bags of 30 microns thickness. Unprocessed berries were used as a control. All experimental studies were performed in triplicate. According to the research results it was found that the weight loss of treated berries was 1,48 – 5,11 % and in the control 11,35 %. The mass fraction of sugars at the end of storage in the treated berries was (2,2–2,6 %), which is 0,2–0,6 times higher than in the control.. The content of ethyl alcohol is fixed in all samples. In the control variant, it was 0,87 %, and in the samples the treatment was from 0,57 – 0,8 % According to the results of the tasting evaluation, the best performance was in the sample with a concentration of 0,5 % Pretreatment of strawberry berries with aqueous solutions of low molecular weight chitosan has a positive effect on the quality of strawberry berries and can be used as an effective tool in the storage of berries

Viscosity of Aqueous Polysaccharide Solutions and Selected Homogeneous Binary Mixtures

The viscosity (η) of dextran (Dex), methyl cellulose (MC), hydroxypropylmethyl cellulose (HPMC), κ-carrageenan (KC), alginate (Alg), and carboxymethyl cellulose (CMC) was measured as a function of the shear rate (γ̇) over a broad range of concentrations both in salt-free water and in 0.1 M NaCl. The concentration (C) dependence of the Newtonian viscosity (η0) was found to be universal for neutral polysaccharides and anionic polysaccharides in 0.1 M NaCl when C was multiplied with the intrinsic viscosity. The dependence was compared with theoretical predictions assuming dominant hydrodynamic or dominant topological interactions. The effect of electrostatic interactions was observed for anionic polysaccharides in salt-free water but not at higher concentrations. Master curves of the shear thinning behavior at different concentrations were obtained when η/η0 was plotted versus τ. γ̇, with τ being a concentration-dependent time that characterizes the onset of shear thinning. Binary mixtures of two neutral polysaccharides (MC and HPMC), two anionic polysaccharides (Alg and CMC), and a neutral (Dex) and anionic polysaccharide (KC) were investigated as a function of the composition and the total polysaccharide concentration. The behavior of the first two mixtures was similar to that of a single polysaccharide with an intermediate intrinsic viscosity. Significant synergy was observed for the third type of mixtures in salt-free water demonstrating the important effect of electrostatic interactions between charged polysaccharides at low concentrations even in concentrated solutions of neutral polysaccharides.

Characteristics of fish gelatin-anionic polysaccharide complexes and their applications in yoghurt: Rheology and tribology

In this study, the rheological and tribological properties of complex solutions comprising of fish gelatin (FG)-Arabic gum (AG), FG-xanthan gum (XG), and FG-κ-carrageenan (κC), respectively, were measured, as well as the effects of the complex on the physical properties of yoghurt. Results showed that with increased XG and κC concentrations, the viscosity of FG-XG and FG-κC complex solutions both increased. It was also found that the lubrication properties of FG-anionic polysaccharide (AP) solutions decreased with the increased AP contents. The applications of FG-AP complexes (FG:AP = 9:1) improved firmness, water holding capacity and viscosity of yoghurt by the formation of large aggregates, but gels were easily destroyed at high frequency. Moreover, compared with gelatin, FG-AP complexes made yoghurt better lubrication properties during low and medium sliding speed, especially for FG-XG complexes. Thus, FG-AP complexes have the potential to be applied in producing yoghurt with good quality.

Bacterial Cellulose (Komagataeibacter rhaeticus) Biocomposites and Their Cytocompatibility.

A series of novel polysaccharide-based biocomposites was obtained by impregnation of bacterial cellulose produced by Komagataeibacter rhaeticus (BC) with the solutions of negatively charged polysaccharides—hyaluronan (HA), sodium alginate (ALG), or κ-carrageenan (CAR)—and subsequently with positively charged chitosan (CS). The penetration of the polysaccharide solutions into the BC network and their interaction to form a polyelectrolyte complex changed the architecture of the BC network. The structure, morphology, and properties of the biocomposites depended on the type of impregnated anionic polysaccharides, and those polysaccharides in turn determined the nature of the interaction with CS. The porosity and swelling of the composites increased in the order: BC–ALG–CS > BC–HA–CS > BC–CAR–CS. The composites show higher biocompatibility with mesenchymal stem cells than the original BC sample, with the BC–ALG–CS composite showing the best characteristics.

Using biochemical agents to intensify the treatment of highly concentrated drilling wastewater

Introduction. The co-authors have developed a new approach to the treatment of highly concentrated drilling wastewater (DWW). The approach is based on the enzymic degradation of polysaccharides that drilling wastewater contains. The research objective is to perform an experimental evaluation of the ability of this biochemical agent to intensify the process of removal of solid impurities from highly concentrated polysaccharide-containing DWW. Materials and methods. The research was performed using standardized test solutions of polysaccharides (carboxymethyl cellulose (CMC), xanthane gum, guar gum), highly concentrated DWW-containing polysaccharides. The reliability of results is ensured by certified methods of analysis, included into the Federal Register of Measurement Procedures and performed by an accredited laboratory, as well as multiple series of experiments. Results. The ability of the biochemical agents (brewing waste (BW) and an enzymatic agent (EP)) to intensify the process of removal of solid impurities from highly concentrated DWW-containing polysaccharides is identified experimentally. The efficiency of biochemical agents used in the process of treatment is determined. The biological degradation of CMC and guar gum solutions is faster than the natural biological degradation that involves BW. Depolymerization time is detected for CMC and guar gum solutions that contain EP. Conclusions. The co-authors have developed a cheaper and more environmentally friendly alternative to existing solutions. It represents a biological method of solid impurities removal from highly concentrated BWW-containing polysaccharides. The use of brewing waste products (BW) as a source of microorganisms, that trigger the polysaccharide hydrolysis, is theoretically substantiated and experimentally proven as a method of treatment of highly concentrated BWW-containing polysaccharides. The expediency of using biochemical agents (BW and EP in isolation) to accelerate the settling rate of solid components of highly concentrated BWW is proven experimentally.

Evaluating the Utility of Permethylated Polysaccharide Solution NMR Data for Characterization of Insoluble Plant Cell Wall Polysaccharides.

Plant cell wall polysaccharide analysis encompasses the utilization of a variety of analytical tools, including gas and liquid chromatography, mass spectrometry (MS), and nuclear magnetic resonance (NMR) spectroscopy. These methods provide complementary data, which enable confident structural proposals of the many complex polysaccharide structures that exist in the complex matrices of plant cell walls. However, cell walls contain fractions of varying solubilities, and a few techniques are available that can analyze all fractions simultaneously. We have discovered that permethylation affords the complete dissolution of both soluble and insoluble polysaccharide fractions of plant cell walls in organic solvents such as chloroform or acetonitrile, which can then be analyzed by a number of analytical techniques including MS and NMR. In this work, NMR structure analysis of 10 permethylated polysaccharide standards was undertaken to generate chemical shift data providing insights into spectral changes that result from permethylation of polysaccharide residues. This information is of especial relevance to the structure analysis of insoluble polysaccharide materials that otherwise are not easily investigated by solution-state NMR methodologies. The preassigned NMR chemical shift data is shown to be vital for NMR structure analysis of minor polysaccharide components of plant cell walls that are particularly difficult to assign by NMR correlation data alone. With the assigned chemical shift data, we analyzed the permethylated samples of destarched, alcohol-insoluble residues of switchgrass and poplar by two-dimensional NMR spectral profiling. Thus, we identified, in addition to the major polysaccharide components, two minor polysaccharides, namely, <5% 3-linked arabinoxylan (switchgrass) and <2% glucomannan (poplar). In particular, the position of the arabinose residue in the arabinoxylan of the switchgrass sample was confidently assigned based on chemical shift values, which are highly sensitive to local chemical environments. Furthermore, the high resolution afforded by the 1H NMR spectra of the permethylated switchgrass and poplar samples allowed facile relative quantitative analysis of their polysaccharide composition, utilizing only a few milligrams of the cell wall material. The concepts herein developed will thus facilitate NMR structure analysis of insoluble plant cell wall polysaccharides, more so of minor cell wall components that are especially challenging to analyze with current methods.

Hyaluronic Acid: The Influence of Molecular Weight on Structural, Physical, Physico-Chemical, and Degradable Properties of Biopolymer.

Hyaluronic acid, as a natural linear polysaccharide, has attracted researchers’ attention from its initial detection and isolation from tissues in 1934 until the present day. Due to biocompatibility and a high biodegradation of hyaluronic acid, it finds wide application in bioengineering and biomedicine: from biorevitalizing skin cosmetics and endoprostheses of joint fluid to polymeric scaffolds and wound dressings. However, the main properties of aqueous polysaccharide solutions with different molecular weights are different. Moreover, the therapeutic effect of hyaluronic acid-based preparations directly depends on the molecular weight of the biopolymer. The present review collects the information about relations between the molecular weight of hyaluronic acid and its original properties. Particular emphasis is placed on the structural, physical and physico-chemical properties of hyaluronic acid in water solutions, as well as their degradability.

Tixotropic Properties of Solutions of Some Polysaccharides

The thixotropic properties of aqueous solutions of the following polysaccharides are studied: chitosan, its water-soluble derivative the sodium salt of chitosan succinamide, and the sodium salt of carboxymethyl cellulose. These polymers have been selected due to their physiological activity and the possibility of using them for biomedical purposes. Studying the effect of the polymer concentration on rheological behavior shows that if a dilute polysaccharide solution is taken for research, then the flow curve does not actually depend on the time of exposure to the shear strain; i.e., the system is thixostable and in equilibrium, in contrast to semidiluted solutions, which clearly demonstrate nonequilibrium and thixotropy. The solutions of the studied polysaccharides behave like thixotropic systems only in the concentration region where supramolecular structures are uniquely formed and the time required for their destruction is comparable with the experiment’s time.

Nonlinear friction dynamics in the cognitive process of food textures: Thickness of polysaccharide solution.

"Thickness" is one of the descriptors of texture in liquid and semisolid foods. In this study, friction in thickener aqueous solutions was evaluated, using a biomimetic friction evaluation system, to show the correlation between friction data and sensory thickness and the recognition mechanism of this sensation during the process of eating. This system can measure friction forces under sinusoidal movement on fractal agar gel, which mimics the morphology and physical properties of the tongue. We found that an increase in the viscosity of the thickener aqueous solution was responsible for both the sensory score of thickness and the asymmetric profile of the friction coefficient in a reciprocating motion. In the case of low viscosity liquids such as water, many of the subjects did not feel thickness, and the friction profile "stable pattern I," that is, a static friction coefficient larger than kinetic friction and a similar profile in the outward and inward processes were observed. However, in the case of solutions containing 3 or 5 wt% of food thickener, the friction profile "unstable pattern I," that is, different friction behaviors in the outward and inward processes, was observed, and many of the subjects experienced strong thickness. In addition, the static friction coefficient at the first cycle was small, and the changes of friction coefficient by the reciprocating motion being repeated was large. These friction phenomena can occur in the mouth and are expected to induce sensory thickness.

INFLUENCE OF THE MODIFICATION TYPE OF CHITOSAN WITH CARBONYL-CONTAINING COMPOUNDS ON THE PROPERTIES OF FORMED FILM MATERIALS

The features of the modification of acid-soluble chitosan by carbonyl-containing compounds in solution and by the method of surface modification of molded materials are investigated. The dependence of the rheological properties of polysaccharide solutions on the structure of the hydrocarbon radical of the modifier is established. The formed films based on iminochitosans, obtained by the interaction of the polymer with aldehydes in a solution of acetic acid, have lower surface, hydrophobic, and strength characteristics compared to chitosan films. The possibility of biodegradation of the obtained materials, as well as the dependence of the mass loss of the samples on the HLB level, which can be used to create wound dressings with programmed degradation, is shown.

Glycerol as a green solvent for enhancing the formulation of dextran methacrylate and gellan-based semi-interpenetrating polymer networks

Recently, glycerol has been exploited in a number of industrial applications, thanks to its high availability, its low cost and, overall, its peculiar properties which fit well with the green chemistry principles. In this work, the ability of glycerol to solubilize high molecular weight polymers and to allow the formation of glycerol-based semi-interpenetrating polymer networks, called “gly-semi-IPNs”, has been investigated. Compared to water, glycerol deeply affects the structural properties of the biopolymers, especially with reference to their chain flexibility. Among the polysaccharides, dextran methacrylate (DexMA) and gellan gum (Ge) were selected. Glycerol solutions of both polysaccharides and their mixtures, as well as a DexMA network (obtained by cross-linking in glycerol and in the presence of a photoinitiator), were rheologically characterized to assess the role of the solvent on the chain conformation and on the mechanical properties of the networks. Interestingly, glycerol was found to deeply influence the mechanical, morphological and optical properties of the formed hydrogels, as well as to improve the cross-linking kinetic of DexMA. Furthermore, glycerol leads to more homogeneous mixtures of the two polysaccharides than those observed in aqueous buffers. As such, novel gly-semi-IPNs, with enhanced formulation and mechanical properties, were prepared and characterized.

Power Laws Dominate Shear and Extensional Rheology Response and Capillarity-Driven Pinching Dynamics of Entangled Hydroxyethyl Cellulose (HEC) Solutions

Quantitative studies of capillarity-driven pinching and extensional rheology of aqueous solutions of polysaccharides like hydroxyethyl cellulose (HEC) are beyond the measurable range of most extens...

Effects of κ-carrageenan on pullulan’s rheological and texture properties as well as pullulan hard capsule performances

κ-Carrageenan (κ-Ca) is often used to facilitate gelling of aqueous solutions of polysaccharides. However, studies on its effects on pullulan’s rheological and texture properties and pullulan (PUL) hard capsule performances have rarely been reported. Herein, effects of κ-Ca on PUL solutions, hydrogels, films and hard capsules were investigated. It was found that the gelling temperature of 15 % (w/w) PUL solutions with 0.07 % KCl increased from 34 ℃ to 42 ℃ as the concentration of κ-Ca increased from 0.6 % to 1.2 %, and the gelling temperature rose from 25 ℃ to 37 ℃ by adding a small amount of KCl (0.07 %) for 15 % PUL solutions with 0.9 % κ-Ca. As the κ-Ca concentration increased, hardness, fracturability and adhesiveness rose for PUL gels and tensile stress increased for PUL films. PUL capsules could be easily prepared by the aid of κ-Ca, and performances of capsules could be adjusted by changing the amount of κ-Ca.

Two-phase flow in microfluidic-chip design of hydrodynamic filtration for cell particle sorting.

As one of the flow-based passive sorting, the hydrodynamic filtration using a microfluidic-chip has shown to effectively separate into different sizes of subpopulations from cell or particle suspensions. Its model framework involving two-phase Newtonian or generalized Newtonian fluid (GNF) was developed, by performing the complete analysis of laminar flow and complicated networks of main and multiple branch channels. To predict rigorously what occurs in flow fields, we estimated pressure drop, velocity profile, and the ratio of the flow fraction at each branch point, in which the analytical model was validated with numerical flow simulations. As a model fluid of the GNF, polysaccharide solution based on Carreau type was examined. The objective parameters aiming practical channel design include the number of the branches and the length of narrow section of each branch for arbitrary conditions. The flow fraction and the number of branches are distinctly affected by the viscosity ratio between feed and side flows. As the side flow becomes more viscous, the flow fraction increases but the number of branches decreases, which enables a compact chip designed with fewer branches being operated under the same throughput. Hence, our rational design analysis indicates the significance of constitutive properties of each stream.

Potential applications of Abelmoschus moschatus polysaccharide as colon release tablets-Rheology and gamma scintigraphic study

In the present scenario of pharmaceutical development, researchers are focusing on the herbal excipients for different delivery systems. This work describes diverse characteristics of novel polysaccharide extracted from the stem of Abelmoschus moschatus (AM). Further, polysaccharide was explored for its potential role as polymer in controlling colon-specific release of metronidazole (MNZ). Cell toxicity study confirmed its safety aspects in biological applications. The aqueous solution of polysaccharide exhibited non-Newtonian pseudoplastic flow property. The consistency coefficient (k) was found to increase with increase in concentration and particle size of AM polysaccharide. Viscosity was found to increase by increasing pH of the aqueous solution of AM. In-vivo gamma scintigraphy study of radiolabeled MNZ tablet in human volunteers confirmed small intestinal transit time of 300–480 min and colon arrival time of 360–480 min. The present study revealed that AM polysaccharide may be a choice of pharmaceutical excipients as an alternative to synthetic polymers.

Shear and extensional rheology of selected polysaccharides

AbstractRheology is used for the elucidation of the flow properties of polysaccharide solutions. For a given polysaccharide, both shear and extensional rheological experiments should be performed for the full characterisation of its flow properties. The provided information will facilitate the efficient exploitation of a polysaccharide in various applications. Although shear rheology is widely used in polysaccharides’ characterisation, there are only limited extensional rheology studies due to lack of reliable techniques in the formation of pure extensional flow. However, recently, several commercial extensional rheometers have been developed and thus, accurate extensional experiments can now be performed. The present work initially presents the principles and concepts of both shear and extensional rheology and then reports rheological findings for solutions of various polysaccharides and their derivatives. Xanthan and various members of the galactomannan, cellulose and alginate families were selected.

Production, extraction and characterization of Chlorella vulgaris soluble polysaccharides and their applications in AgNPs biosynthesis and biostimulation of plant growth

Chlorella vulgaris, like a wide range of other microalgae, are able to grow mixotrophically. This maximizes its growth and production of polysaccharides (PS). The extracted polysaccharides have a complex monosaccharide composition (fructose, maltose, lactose and glucose), sulphate (210.65 ± 10.5 mg g−1 PS), uronic acids (171.97 ± 5.7 mg g−1 PS), total protein content (32.99 ± 2.1 mg g−1 PS), and total carbohydrate (495.44 ± 8.4 mg g−1 PS). Fourier Transform infrared spectroscopy (FT-IR) analysis of the extracted polysaccharides showed the presence of N–H, O–H, C–H, –CH3, >CH2, COO−1, S=O and the C=O functional groups. UV–Visible spectral analysis shows the presence of proteins, nucleic acids and chemical groups (ester, carbonyl, carboxyl and amine). Purified polysaccharides were light green in color and in a form of odorless powder. It was soluble in water but insoluble in other organic solvents. Thermogravimetric analysis demonstrates that Chlorella vulgaris soluble polysaccharide is thermostable until 240°C and degradation occurs in three distinct phases. Differential scanning calorimetry (DSC) analysis showed the characteristic exothermic transition of Chlorella vulgaris soluble polysaccharides with crystallization temperature peaks at 144.1°C, 162.3°C and 227.7°C. The X–ray diffractogram illustrated the semicrystalline nature of these polysaccharides. Silver nanoparticles (AgNPs) had been biosynthesized using a solution of Chlorella vulgaris soluble polysaccharides. The pale green color solution of soluble polysaccharides was turned brown when it was incubated for 24 hours with 100 mM silver nitrate in the dark, it showed peak maximum located at 430 nm. FT-IR analysis for the biosynthesized AgNPs reported the presence of carbonyl, –CH3, >CH2, C–H,–OH and –NH functional groups. Scanning and transmission electron microscopy show that AgNPs have spherical shape with an average particle size of 5.76. Energy-dispersive X-ray (EDX) analysis showed the dominance of silver. The biosynthesized silver nanoparticles were tested for its antimicrobial activity and have positive effects against Bacillus sp., Erwinia sp., Candida sp. Priming seeds of Triticum vulgare and Phaseolus vulgaris with polysaccharides solutions (3 and 5 mg mL−1) resulted in significant enhancement of seedling growth. Increased root length, leaf area, shoot length, photosynthetic pigments, protein content, carbohydrate content, fresh and dry biomass were observed, in addition these growth increments may be attributed to the increase of antioxidant activities.

Antibacterial activity of Osmunda japonica (Thunb) polysaccharides and its effect on tomato quality maintenance during storage

AbstractTomatoes are rich in nutrients, yet they have a short shelf life and are prone to decay due to bacterial invasion. Polysaccharides extracted from Osmunda japonica (Thunb) were briefly characterised. The inhibitory effect of polysaccharides on nine kinds of common spoilage and pathogenic bacteria in tomatoes stored postharvest was studied, and the polysaccharides had broad‐spectrum antibacterial and antifungal activities against many tested strains. The minimum inhibitory concentrations (MICs) and the minimum bactericidal (fungicidal) concentrations (MBCs) were determined, and the lowest MBC against Bacillus cereus was 0.15 g L−1. Various concentrations of an O. japonica (Thunb) polysaccharide (OP) solution were sprayed onto ordinary preservation paper, which then distinctly maintained tomato freshness. OP delayed vitamin C (VC) and titratable acid decreases and increased respiratory intensity in a dose‐dependent manner, reducing malondialdehyde accumulation. The tomatoes could be stored for 30 day at 25 ± 1 °C. OP has potential as a safe, nontoxic natural plant preservative.

Fabrication and Characterization of Polysaccharide Composite Films from Polyion Complex Particles.

Biomaterials made of natural polysaccharides have attracted much attention due to the fact of their excellent properties, such as high biocompatibility and biodegradability, and their specific biological functions based on their chemical structures. This study demonstrates that polysaccharide composite films can be fabricated from polyion complexes (PICs) with their particles used as building components. Dispersion of PIC particles prepared by mixing, centrifugation, and re-dispersion of dilute solutions of cationic and anionic polysaccharides were cast, dried, and formed into films several micrometers thick. These films were homogenous and water insoluble. It was revealed that the component anionic polysaccharides affected the film’s properties such as the swelling behavior and mechanical characteristics. Adhesion of NIH3T3 cells (integrin: high, CD44: lack or weak) and A549 cells (integrin: high, CD44: high) to the composite films were examined. Both NIH3T3 and A549 cells adhered to heparin/chitosan (HEP/CHI) film because HEP has an affinity for integrin through fibronectin. However, A549 cells adhered to chondroitin sulfate (CS)/CHI and hyaluronic acid (HYA)/CHI films, whereas NIH3T3 cells did not, because both CS and HYA have affinity for CD44. These results indicated that the biological functions of anionic polysaccharides were maintained on the surface of the composite films. It was also possible to fabricate films composed of three kinds of polysaccharides: one cationic polysaccharide and two kinds of anionic polysaccharides. These results show that the properties of films composed of three kinds of polysaccharides may be controllable depending on the anionic polysaccharide composition rates.