Polysaccharide Solutions Research Articles

Characterization of ulvan polysaccharide extracted from Ulva pertusa and its effect on thermal, rheological, and gelling properties of rice flour

Three ulvan fractions (UPs 1–3) were extracted from Ulva pertusa via hot-water extraction. UP1 exhibited a molecular weight of 729,151 Da, while UPs 2 and 3 ranged from 19,952 to 750,384 Da. These fractions differed in monosaccharide, uronic acid, and sulfate levels. Zeta potentials for polysaccharide solutions (0.2–0.6 % w/v) ranged from −34.4 to −25.1, all demonstrating shear-thinning behavior. Incorporating UPs 1–3 solutions (0.2–0.6 % w/v) with rice flour increased gelatinization temperatures and modified pasting properties, increasing peak time, peak viscosity, and trough viscosity while reducing breakdown, final, and setback viscosities. Ulvan polysaccharide improved the viscous behavior of rice flour paste, indicated by increased loss modulus and tan δ (p > 0.05). Furthermore, ulvan polysaccharide improved the microstructure and texture of rice flour gel, with UP1 (0.6 % w/v) forming denser matrices and better texture. Molecular docking analysis suggested that hydrogen bonding is the primary interaction between rice glutelin and ulvan components.

Structural and functional properties of polysaccharides extracted from three Dioscorea species

Dioscorea has a history spanning over 2000 years for both medicinal and edible purposes in China. It contains rich polysaccharides, which are frequently utilized as thickening and stabilizing agents in the food industry. However, there has been relatively little focus on polysaccharides from common Dioscorea species besides D. opposita, such as D. alata and D. esculenta. In this study, non-starch crude polysaccharides were isolated from D. opposita (BD), D. alata (WC), and D. esculenta (GZ). Their structures, physicochemical compositions, and functional properties were characterized and compared. The results indicated three polysaccharides all exhibited characteristic peaks of polysaccharides and possessed triple-helix structures. The Glc (36.78–83.90 %), Man (6.71–26.68 %), and GalA (8.54–10.22 %) were identified as the primary monosaccharide components. In terms of functionality, three polysaccharide solutions demonstrated non-Newtonian flow characteristics and displayed commendable thermal stability. It is worth noting that the antioxidant and emulsifying properties of polysaccharides isolated from D. opposita (BD) and D. alata (WC) were superior to those of D. esculenta (GZ), making them more suitable for use as antioxidants and stabilizers. By comparing polysaccharides derived from different Dioscorea species, this study provides valuable insights into the food, cosmetic, and pharmaceutical industries based on the unique properties of these different polysaccharides.

Structure and Dynamics of Water in Polysaccharide (Alginate) Solutions and Gels Explained by the Core-Shell Model.

In both biological and engineered systems, polysaccharides offer a means of establishing structural stiffness without altering the availability of water. Notable examples include the extracellular matrix of prokaryotes and eukaryotes, artificial skin grafts, drug delivery materials, and gels for water harvesting. Proper design and modeling of these systems require detailed understanding of the behavior of water confined in pores narrower than about 1 nm. We use molecular dynamics simulations to investigate the properties of water in solutions and gels of the polysaccharide alginate as a function of the water content and polymer cross-linking. We find that a detailed understanding of the nanoscale dynamics of water in alginate solutions and gels requires consideration of the discrete nature of water. However, we also find that the trends in tortuosity, permeability, dielectric constant, and shear viscosity can be adequately represented using the "core-shell" conceptual model that considers the confined fluid as a continuum.

Synthesis and characterization of polysaccharide-cryogel and its application to the electrochemical detection of DNA

The main goal of our study is to demonstrate the applicability of the PPy-cryogel-modified electrodes for electrochemical detection of DNA. First, a polysaccharide-based cryogel was synthesized. This cryogel was then used as a template for chemical polypyrrole synthesis. This prepared polysaccharide-based conductive cryogel was used for electrochemical biosensing on DNA. Carrageenan (CG) and sodium alginate (SA) polysaccharides, which stand out as biocompatible materials, were used in cryogel synthesis. Electron transfer was accelerated by polypyrrole (PPy) synthesized in cryogel networks. A 2B pencil graphite electrode with a diameter of 2.00 mm was used as a working electrode. The prepared polysaccharide solution was dropped onto a working electrode as a support material to improve the immobilization capacity of biomolecules and frozen to complete the cryogelation step. PPy synthesis was performed on the electrodes whose cryogelation process was completed. In addition, the structures of cryogels synthesized on the electrode surface were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Surface characterization of the modified electrodes was performed by energy-dispersive X-ray spectroscopy (EDX) analysis. Electrochemical determination of fish sperm DNA (fsDNA) was performed using a PPy-cryogel-modified electrode. The use of a porous 3D cryogel intermediate material enhanced the signal by providing a large surface area for the synthesis of PPy and increasing the biomolecule immobilization capacity. The detection limit was 0.98 µg mL−1 in the fsDNA concentration range 2.5–20 µg mL−1. The sensitivity of the DNA biosensor was estimated to 14.8 µA mM−1 cm−2. The stability of the biosensor under certain storage conditions was examined and observed to remain 66.95% up to 45 days.Graphical

ИССЛЕДОВАНИЕ ВЗАИМОДЕЙСТВИЙ БИОПОЛИМЕРОВ БЕЛОК – ПОЛИСАХАРИД, ВЫДЕЛЕННЫХ ИЗ СЕМЯН ЛЬНА

The aim of the study is to investigate the interaction of proteins and polysaccharides obtained from flax seeds. Objectives: to study the phase behavior during the interaction of protein concentrate solutions and flax seed polysaccharides; to investigate the interaction of flax seed proteins and polysaccharides at different pH. The objects of the study were flax seed processing products: protein concentrate, polysaccharide extract and their mixtures. Polysaccharides were isolated from flax seeds by extraction, followed by concentration of the extract using a rotary evaporator and drying in a spray dryer. The protein product was obtained by alkaline extraction from mucus-free and defatted flax seeds. To obtain a homogeneous 1 % protein solution, the product was homogenized, followed by holding the solution at 50 °C and constant stirring for 2 hours. To study protein-polysaccharide interactions, protein and polysaccharide solutions were mixed in the ratios of 9:1, 7:3, 1:1, 3:7, 1:9, respectively. Physicochemical parameters were determined using standard analysis methods. The protein content in the products was determined according to GOST 10846-91, and the humidity was determined according to GOST 10856-96. The pH value was measured using an I-160MI laboratory ion meter. Spectrophotometric analysis methods were performed on a PE-5400 spectrophotometer. As in the bovine serum albumin solution, residues of tryptophan, tyrosine, and phenylalanine were found in the spectrum of flax protein in the UV range. When measuring the optical density of solutions of protein, polysaccharides and their mixtures, the behavior of the system was determined by the content of the predominant component. In acidic environments, mixed systems form two-phase systems regardless of the ratio of components. At equal concentrations of the initial solutions (0.3 %), the mixed systems remained monodisperse and stable at neutral pH and a component ratio of 1:1.

Synergistic effects of selenium and zinc on Bletilla striata (Thunb.) Reichb. F. growth and polysaccharide antioxidation.

Selenium (Se) is a beneficial trace element for plants, while zinc (Zn) is a vital micronutrient. Bletilla striata (Thunb.) Reichb. F. is widely recognized as a medicinal herb. In this study, Se and Zn were introduced to determine the medicinal properties of B. striata. The plant's biomass, polysaccharides, Se and Zn contents, and the antioxidant properties of polysaccharide solutions were all examined. A notable increase in polysaccharide synthesis in B. striata tubers was observed following the application of 0.2 kg ha-1 of Se, and 1.0 kg ha-1 of Zn, either individually or in combination. Se and Zn content in polysaccharides were 3.33 to 3.77 mg kg-1 and 82.82 to 121.78 mg kg-1, at 1.0 kg ha-1 Se and 10.0 kg ha-1 Zn treatments, respectively. These values were 2.1-3.1 times and 1.8-2.8 times higher than those observed in control samples. Polysaccharide antioxidation has resulted in an increase in antioxidant activity as the concentration of polysaccharide solutions increased. The largest scavenging of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals and the most excellent reducingpower of the polysaccharide solutions were observed when a mixture of Se and Zn was applied at a rate of 1.0 kg ha-1 and 10.0 kg ha-1. The individual application of Se at 1.0 kg ha-1 and Zn at 10.0 kg ha-1 also resulted in significant DPPH radicals scavenging and reduced power. These data suggested that Se-Zn enriched B. striata is a new source of Se and Zn supplementation and an antioxidant resource.

Enhancing frozen fish quality through polysaccharide-ice glazing: Insights from physical properties and preservation effects

Polysaccharide ice-glazing is a widely employed method for preserving frozen fish, with the choice of polysaccharide playing a crucial role in preservation effectiveness. This research investigates the impact of various polysaccharides, including neutral polysaccharides like konjac glucomannan (KGM) and pullulan (PUL), as well as ionic polysaccharides such as gellan gum (GG), κ-carrageenan (KC), carboxymethyl cellulose (CMC), and xanthan gum (XG), on the physical properties of ice. Additionally, we assess the influence of polysaccharide ice-glazing on the quality of frozen snakehead (Channa argus) fish fillets. Our study shows that the physical properties of polysaccharide-infused ice are affected by both polysaccharide type and concentration. Increasing the polysaccharide concentration led to a reduction in water activity within the supercooled polysaccharide solution. Additionally, the characteristics of ice formed by the polysaccharide solution, including ice crystal size, compressive strength, sublimation rate, and oxygen permeability, consistently decreased. In our comparative analysis, at equivalent polysaccharide concentrations, the PUL solution exhibited the lowest water activity. Notably, PUL-ice demonstrated superior performance, displaying the smallest ice crystal size, highest compressive strength, lowest ice sublimation rate, and the most effective oxygen permeability barrier. Following this in decreasing order of performance were the GG, KC, CMC, XG, and KGM samples. Moreover, when applied to glazing snakehead fish fillets, pullulan ice-glazing outperformed KGM ice-glazing in preserving fish quality, confirming the direct influence of polysaccharide-induced ice properties on fillet preservation outcomes. This study provides essential insights to guide informed decisions in the field of polysaccharide ice-glazing applications, aimed at enhancing the quality of frozen fish.

Molecular mechanisms of Codonopsis pilosula in inhibiting hepatocellular carcinoma growth and metastasis

BackgroundLiver cancer, one of the most common types of cancer worldwide, accounts for millions of cases annually. With its multi-target and wide-ranging therapeutic effects, traditional Chinese medicine has emerged as a potential approach for treating various tumors. Codonopsis pilosula, a traditional herb, is known for its anti-inflammatory and antioxidant properties. In this study, we investigated the potential molecular mechanisms of Codonopsis pilosula in regulating the inhibition of CDK1 and the modulation of PDK1/β-catenin, which are involved in hepatocellular carcinoma growth and metastasis. Study Design/MethodsFirstly, we screened the active chemical constituents of Codonopsis pilosula and identified their respective target proteins using the Herb database. Then, we applied the GeneCards database and transcriptome sequencing analysis to screen for critical genes associated with the occurrence and development of liver cancer. The intersection of the target proteins and disease-related genes was used to determine the potential targets of Codonopsis pilosula in hepatocellular carcinoma. Protein-protein interaction analysis and GO/KEGG analysis were subsequently performed to uncover the pathways through which Codonopsis pilosula acts on liver cancer. The Huh-7 cell line, exhibiting the highest sensitivity to Codonopsis pilosula polysaccharide solution (CPP) intervention, was chosen for subsequent studies. Cell viability was evaluated using the CCK-8 assay, colony formation assay was conducted to determine cell proliferation capacity, flow cytometry was used to analyze cell cycle, TUNEL staining was performed to assess cell apoptosis, scratch assay was carried out to evaluate cell migration ability, the expression of EMT-related proteins was detected and analyzed, and cell sphere formation assay was conducted to investigate cell stemness. Finally, a liver cancer animal model was established, and different doses of CPP were administered via gavage the next day. The expression levels of CDK1, PDK1, and β-catenin in mouse liver tissues were detected and analyzed, immunohistochemistry staining was performed to assess the expression of tumor cell proliferation-related proteins Ki67 and PCNA in mouse xenografts, and TUNEL staining was carried out to evaluate cell apoptosis in mouse liver tissues. After intervention with CDK1 expression, the expression levels of CDK1, PDK1, and β-catenin proteins and mRNA in each group of cells were detected using Western blot and RT-qPCR. ResultsThrough network pharmacology analysis, transcriptome sequencing, and bioinformatics analysis, 35 target genes through which Codonopsis pilosula acts on liver cancer were identified. Among them, CDK1, with the highest degree in the PPI network, was considered an essential target protein for Codonopsis pilosula in treating liver cancer. In vitro cell experiments revealed that CPP could inhibit the expression of CDK1/PDK1/β-catenin signaling axis factors, suppress cell proliferation, decrease cell migration ability, influence the EMT process, and reduce cell stemness by inhibiting CDK1 and affecting the PDK1/β-catenin signaling axis. Similarly, in vivo experiments demonstrated that CPP could regulate the CDK1/PDK1/β-catenin signaling axis, inhibit tumor growth, and induce cell apoptosis. ConclusionCodonopsis pilosula may inhibit hepatocellular carcinoma growth by suppressing CDK1 and affecting the PDK1/β-catenin signaling axis, limiting cell EMT and reducing cell stemness. These findings provide insights into the potential therapeutic role of Codonopsis pilosula in liver cancer.

Synthesis and characterization of polysaccharide- and protein-based edible films and application as packaging materials for fresh fish fillets

The rising packaging industry together with global demand for sustainable production has increased the interest in developing biodegradable packaging materials. The aim of the study was to develop edible films based on pectin, gelatin, and hydroxypropyl methylcellulose and evaluate their applicability as biodegradable packaging materials for gilthead seabream fillets. Mechanical properties, water barriers, wettability of the films through contact angle measurement, optical, and UV–Vis barrier properties were evaluated for food packaging applications. The effective blend of polysaccharide and protein film-forming solutions was confirmed by the produced films with excellent optical properties, acceptable mechanical properties and adequate barriers to water vapor. The contact angle for pectin based and gelatin based films were higher than 90° indicating the hydrophobic films, while HPMC based films had contact angle lower than 90°. The produced films were tested as alternative and environmentally friendly packaging materials for gilthead seabream fillets during refrigerated storage. All tested packaging conditions resulted in similar shelf-life in packed gilthead seabream fillets (i.e. 7–8 days at 2 °C). The results showed that the developed films may reduce the use of conventional petroleum-based food packaging materials without affecting the shelf-life of fish.

Neutron Scattering Analysis of Cryptococcus neoformans Polysaccharide Reveals Solution Rigidity and Repeating Fractal-like Structural Patterns.

Cryptococcus neoformans is a fungal pathogen that can cause life-threatening brain infections in immunocompromised individuals. Unlike other fungal pathogens, it possesses a protective polysaccharide capsule that is crucial for its virulence. During infections, Cryptococcus cells release copious amounts of extracellular polysaccharides (exo-PS) that interfere with host immune responses. Both exo-PS and capsular-PS play pivotal roles in Cryptococcus infections and serve as essential targets for disease diagnosis and vaccine development strategies. However, understanding their structure is complicated by their polydispersity, complexity, sensitivity to sample isolation and processing, and scarcity of methods capable of isolating and analyzing them while preserving their native structure. In this study, we employ small-angle neutron scattering (SANS) and ultra-small-angle neutron scattering (USANS) for the first time to investigate both fungal cell suspensions and extracellular polysaccharides in solution. Our data suggests that exo-PS in solution exhibits collapsed chain-like behavior and demonstrates mass fractal properties that indicate a relatively condensed pore structure in aqueous environments. This observation is also supported by scanning electron microscopy (SEM). The local structure of the polysaccharide is characterized as a rigid rod, with a length scale corresponding to 3-4 repeating units. This research not only unveils insights into exo-PS and capsular-PS structures but also demonstrates the potential of USANS for studying changes in cell dimensions and the promise of contrast variation in future neutron scattering studies.

Sodium Carboxymethylcellulose Rheological Behavior in a Water Mixture for Pharmaceutical and Biomedical Applications

Sodium carboxymethylcellulose Na-CMC is derived from cellulose fibers. Knowledge of the behavior of Na-CMC as a charged polysaccharide in solution is important, because most of its biomedical industrial applications utilize its solutions. The main objective of our research described here was to determine the rheological and viscometric properties of polysaccharide solutions of Na-CMC in water (W), as a function of the cutting speed and the polymer concentration. The evolution of reduced dynamic viscosities and the effect of the Gibbs energy of Na-CMC in W were characterized as a function of the temperature (15 °C to 45 °C), and concentration (1 to 10) g/l. We identified three main concentration regimes, corresponding to a dilute regime, a critical regime, and the semi-dilute regime. The thermodynamic parameters of the viscosity also supported the obtained results. Our results show that Na-CMC/W is a promising solvent mixture for use in pharmaceutical and antibacterial applications.

STUDY OF DOUGH FERMENTATION PROCESS WITH FLAX SEEDS

Flax seeds are a valuable raw material for the production of functional bakery products. The article investigates the fermentation processes in wheat dough supplemented with whole and crushed flax seeds in dry and soaked states. For a holistic understanding of the fermentation process, the regularities of the kinetics and dynamics of gas formation in the experimental samples were analyzed. It was found that during fermentation in samples with whole flax seeds in dry and soaked states, the amount of carbon dioxide released slightly increases compared to the control. In the samples with crushed dry and soaked flax seeds, the total amount of carbon dioxide released is higher than in the control sample by 16.5% and 19.0%, respectively. In the sample with crushed flax seeds, the nature of the dynamics of carbon dioxide release differs from the control sample, namely, a one-stage fermentation is observed. At the same time, the peak of carbon dioxide release was observed almost 30 minutes later than in the control sample. This may be due to the fact that soaking flaxseed products produces viscous solutions of polysaccharides, which envelop the yeast cells during dough kneading and slow down the supply of nutrients to them. Based on the analysis of the dynamics of carbon dioxide emission, it is recommended to reduce the duration of dough fermentation for the sample with whole flax seeds to 90 minutes, and for the samples with crushed seeds and soaked flax products to 60 minutes, so that the most intense carbon dioxide emission in these experimental samples occurs during the period of proofing of dough pieces. It was found that the introduction of whole and crushed flax seeds in soaked form slows down the rise of the dough due to the thickening of the dough system with water-soluble and insoluble flax dietary fiber, reducing fermentation and the formation of sugars in the dough system.

Self-Healing of Pluronic® F127 Hydrogels in the Presence of Various Polysaccharides.

Thermoresponsive Pluronic® F127 (PL) gels in water were investigated through rheological tests in different shear conditions. The gel strength was tuned with the addition of 1% polysaccharide solution. In the presence of xanthan gum (XG), the viscoelastic behavior of PL-based hydrogels was improved in aqueous environment, but the rheological behavior was less changed with the addition of XG in PBS solutions, whereas in the presence of 0.1 M NaCl, the viscoelastic parameters decreased. PL micellar networks exhibited a self-healing ability, recovering their initial structure after applying cycles of high strain. The rheological characteristics of the PL hydrogel changed with the addition of 1% polysaccharides (xanthan gum, alginate, κ-carrageenan, gellan, or chitosan). PL/polysaccharide systems form temperature-responsive hydrogels with shear thinning behavior, yield stress, and self-healing ability, being considered a versatile platform for injectable biomaterials or bioinks. Thus, in the presence of xanthan gum in aqueous medium, the gel strength was improved after applying a high strain (the values of elastic modulus increased). The other investigated natural polymers induced specific self-healing behaviors. Good performances were observed with the addition of gellan gum, alginate, and κ-carrageenan, but for high values of strain, the ability to recover the initial structure decreased. A modest self-healing behavior was observed in the presence of chitosan and xanthan gum dissolved in NaCl solution.

Eco-friendly unfired clay materials modified by natural polysaccharides

This study is devoted to the evaluation of the effect of natural polysaccharide (starch, alginate, and chitosan) solutions on the properties of clay composite. The authors describe the technology for obtaining gelated biopolymers (using hot and cold-water treatment and, acid treatment), as well as some characteristics of the obtained solutions, such as viscosity and pH. Some characteristics, such as bulk density, shrinkage, compressive strength, hygroscopic behavior, and water erosion resistance, are determined for the clay composites modified with biopolymer solutions. With increasing the concentration of biopolymer in solution, the bulk density and shrinkage values of the clay composite materials decrease. Also, the application of starch (2.5–10%) and alginate (2.5–7.5%) solutions has a positive effect on the compressive strength of the clay composite, with an increasing about 18–42%. Moreover, the addition of biopolymer solutions leads to an increase in the moisture adsorption degree of clay composites up to 34.2%. Finally, some biopolymers affect the structure and change the water erosion behaviour of clay composite.

Preparation and analysis of polysaccharide from Solanum tuberdsm

The crude Solanum tuberdsm polysaccharides (STP) were extracted with hot water. In the process of extraction, proteins, pigments, small molecules and salts in the mixture were removed by Sevage reagent, diatomite and distilled water dialysis, respectively. In addition, the process conditions of protein removal by response surface methodology (RSM) were optimized, and the optimum process conditions of Sevage method were established as follows: ultrasound power 350 W, ultrasound time 20 min, deproteinization twice, volume ratio of polysaccharide solution to Sevage reagent 1:1 (mL/mL). Under these conditions, the protein removal rate was 93.14%.

Effect on the Viscometric Properties of Sodium Carboxymethylcellulose in a Dimethylacetamide and Acetone Mixture

The main objective of our research described here was to determine the viscometric properties of polysaccharide solutions of sodium carboxymethyl cellulose (CMC) in dimethylacetamide (DMA)/acetone (A) mixtures. The evolution of the dynamic and intrinsic viscosities and the effect of the intrinsic Gibbs energy of CMC in DMA/A (44 ml/6 ml) were characterized as a function of the temperature (293.15 to 318.15) K, and concentration (1 to 10) g/l. We identified four main concentration regimes, corresponding to an absorption regime, a dilute regime, a critical regime, and the semi-dilute regime. The thermodynamic parameters of the viscosity also supported the obtained results. Exploiting our results, CMC/DMA/A is a promising solvent mixture for use in pharmaceutical and antibacterial applications.

Structural and mechanical analysis on mannuronate-rich alginate gels and xerogels beads based on Calcium, Copper and Zinc as crosslinkers

Beads based on a mannuronate(M)-rich alginate (86 % M units) were prepared by adding the polysaccharide solution to a crosslinking bath containing different concentrations (0.5, 2 and 10 wt%) of XCl2 where X = Ca, Cu or Zn. Primarily focus was on Zn, due to its antioxidant, anti-inflammatory and anti-microbial capabilities. The beads were characterized by Field-Emission Scanning Electron Microscopy (FESEM), Fourier-Transform Infra-Red spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Small-Angle X-ray Scattering (SAXS) and compression tests. The crosslinking agent significantly influenced the properties of the resulting beads. Specifically, Ca-based beads exhibited a smoother surface, while Cu- and Zn-based beads appeared rougher. Interestingly, Zn-based beads displayed a core-shell structure. Young moduli ranged from 3500 and 7000 MPa, with the highest values observed for Zn-beads. SAXS investigation at 0.5 wt% XCl2 suggested increase in the densely packed domains amount in the order: Ca < Cu < Zn. Extended X-ray Absorption Fine Structure (EXAFS) showed that the coordination number was 4.3 ± 0.4 for Cu, and 4.0 ± 0.2 and 1.1 ± 0.1 for Zn in 0.5 wt% XCl2 alginate xerogels, in agreement with reported Density Functional Calculations on Cu2+– and Zn2+–MM complexes. The results from FT-IR, compositional analysis and EXAFS collectively suggested a bridging coordination for these systems.

DECOMPOSITION OF PHOSPHORUS-CONTAINING COMPOUNDS IN AQUEOUS AND POLYSACCHARIDE SOLUTIONS OF ORGANIC ACIDS

The purpose was to study the patterns of dissolution (solubilization) of phosphorus-containing minerals in aqueous and polysaccharide solutions of organic acids in order to model the mechanism of mineral destruction by soil bacteria synthesizing organic acids and exopolysaccharides. Methods. Model, laboratory-analytical, microbiological, statistical. Results. The destructive effect of organic acids on minerals is manifested both in aqueous and polysaccharide solutions. The introduction of bacterial polysaccharide into an aqueous solution of acids increases the decomposition of phosphorus-containing minerals by 1.34̶ 4.96 times. The influence of the chemical structure of acid molecules on the intensity of mineral decomposition is mainly manifested in the presence of bacterial polysaccharide, while in an aqueous solution the effectiveness of acid action depends on the nature of the mineral being destroyed. To the maximum degree, polysaccharide increases the destruction of minerals in a solution of citric acid: molten magnesium phosphate ̶ 2.55 times, thermophosphate ̶ 2.11 times, phosphate flour ̶ 4.96 times. Decomposition of phosphorus compounds in solutions of ascorbic and oxalic acids enhances bacterial polysaccharide to a lesser extent than in citric acid solution. Modeling the destruction of phosphorus-containing minerals under non-sterile conditions (soil conditions) made it possible to establish that organic acids under non-sterile conditions are subject to consumption by soil microbiota, especially ascorbic and citric acids, and to a lesser extent - succinic. Aqueous solutions of organic acids after 18 hours of incubation in non-sterile conditions lose their leaching activity by 1.06 ̶12.1 times. The introduction of a polysaccharide into aqueous solutions of acids makes it possible to avoid their rapid consumption by microorganisms, because of which the efficiency of mineral leaching under non-sterile conditions decreasшes by only 5–20% compared to sterile ones. Conclusions. The introduction of a bacterial polysaccharide into a solution of organic acids enables the latter to be transferred to a sorbed state, as a result of which their susceptibility to consumption by microorganisms is sharply reduced. Thus, polysaccharide-forming bacteria not only destroy minerals more intensively than microorganisms synthesizing only low-molecular-weight metabolites, but also synthesize a more stable and long-term functioning leaching complex in the soil.

Influence of Ultrasound on the Properties of Polysaccharide Complexes and Materials Based on Them

Freeze-drying is often used as a final stage to produce three-dimensional porous matrices for medicine. Because a pure solvent crystallizes first during freezing, it acts as a pore-forming agent. The size of the solvent crystals primarily depends on the cooling rate and the composition of the material to be frozen. Ultrasonic treatment also affects the size of crystals and can be used to control the structure of a porous matrix. This article describes the effect of ultrasound (40 kHz, 50 W) applied at the preliminary freezing stage of polysaccharide solutions (alginate, chitosan, alginate–chitosan and alginate–gelatin) on the finished matrix properties. The most attention was paid to the effect of ultrasound on the size and shape of crystals formed during freezing, which leads to a change in the porous structure of the matrices after solvent sublimation. As a result of changes in the microstructure, a number of differences in the vibrational spectra of the molecules and the values of pore volume, sorption capacity, permeability and degradation of matrices were identified. Such changes in the structure of materials, as well as the emerging directionality of pores, together can affect the process of cell cultivation in these polysaccharide matrices, which can be useful in solving problems of tissue engineering.

Time-dependent thixotropy of dysphagia management-oriented polysaccharide solutions

During dysphagia management, the required foods are often thixotropic yield fluids (YSFs) in which polysaccharide gums are used as thickeners or gelling agents. Thixotropy is a prevalent hysteresis phenomenon in YSFs, so it always occurs as an apparently time-dependent stress or modulus response. The yielding behavior of the food bolus is inseparable from the mastication and swallowing process, among which time-dependent thixotropy is integral. Nevertheless, standardizing and generalizing the thixotropy levels has always been a challenge in the manufacturing application of YSFs. Moreover, the existing thixotropic approaches cannot guarantee the accuracy and comparability of the measurement process due to technicalities. Along these lines, in this work, the thixotropic stress-shear rate hysteresis loops were investigated based on the utilization of dysphagia management-oriented model polysaccharide solutions that exhibited different time-dependent thixotropy levels. More specifically, xanthan gum (XG), carboxymethylated curdlan (CMCD), and konjac glucomannan (KGM) solutions were selected to mimic dysphagia diet construction, whereas the relationship between their technically mechanical properties and structural changes was analyzed. Compared with the KGM solutions, both XG and CMCD solutions presented significant thixotropy levels with different timescale responses and concentration dependence. The recorded discrepancy in their loop area and shape were attributed to their different intermolecular association and networks.