Single Polysaccharide Research Articles

Fabrication and characterization of non-fat whipped cream analogue: Effects of type and concentration of polysaccharide

In the present study, the non-fat whipped cream analogue was formulated by the combination of soy protein isolate, different polysaccharides and sucrose. Compared with single polysaccharide, the combined polysaccharide showed synergistic effect on formulating the non-fat whipped cream with better properties. The non-fat whipped creams showed high overrun (up to 570 %), excellent drainage stability (no drainage occurred within 120 min) and comparable hardness (up to 1.1 N) than that of control (a commercially dairy whipped cream). Moreover, the non-fat whipped creams were all solid-like (storage modulus > loss modulus) and exhibited outstanding shape retention ability. These properties were greatly affected by the types and ratios of combined polysaccharide. The combination of anionic and neutral polysaccharides was more beneficial for its properties, and the effect depended on the combined ratios. Especially for samples containing gellan gum/guar gum, their appearance only changed slightly after standing for 60 min, and simultaneously showed satisfying sensory acceptability when the combined ratio was 2/3. Therefore, these novel non-fat whipped creams could be popularized as the functional products aiming at specific groups such as diabetes and obesity people in the future.

Glycosyl transferase GT2 genes mediate the biosynthesis of an unusual (1,3;1,4)-β-glucan exopolysaccharide in the bacterium Sarcina ventriculi.

Linear, unbranched (1,3;1,4)-β-glucans (mixed-linkage glucans or MLGs) are commonly found in the cell walls of grasses, but have also been detected in basal land plants, algae, fungi and bacteria. Here we show that two family GT2 glycosyltransferases from the Gram-positive bacterium Sarcina ventriculi are capable of synthesizing MLGs. Immunotransmission electron microscopy demonstrates that MLG is secreted as an exopolysaccharide, where it may play a role in organizing individual cells into packets that are characteristic of Sarcina species. Heterologous expression of these two genes shows that they are capable of producing MLGs in planta, including an MLG that is chemically identical to the MLG secreted from S. ventriculi cells but which has regularly spaced (1,3)-β-linkages in a structure not reported previously for MLGs. The tandemly arranged, paralogous pair of genes are designated SvBmlgs1 and SvBmlgs2. The data indicate that MLG synthases have evolved different enzymic mechanisms for the incorporation of (1,3)-β- and (1,4)-β-glucosyl residues into a single polysaccharide chain. Amino acid variants associated with the evolutionary switch from (1,4)-β-glucan (cellulose) to MLG synthesis have been identified in the active site regions of the enzymes. The presence of MLG synthesis in bacteria could prove valuable for large-scale production of MLG for medical, food and beverage applications.

Effect and characterization of konjac glucomannan on xanthan gum/κ-carrageenan/agar system

A mixed polysaccharide system is an important strategy to improve the performance of a single polysaccharide. Herein, quaternary polysaccharide gels were prepared by konjac glucomannan (KGM), xanthan gum (XG), κ-carrageenan (κ-CA), and agar (AR). The effects of KGM were evaluated by combining water holding capacity (WHC), rheological analysis, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and texture profile analysis (TPA). More KGM gradually increased the springiness of the compounded gels. WHC increased and then decreased with the addition of KGM, performing best at KGM4 (KGM: κ-CA:XG:AR = 2:2:1:2). Rheological analysis showed that the compounded gels exhibited a pseudoplastic characteristic of shear thinning, KGM endowed the gel with a stronger shear thinning behavior and improved the solid-like nature of the gels at high temperatures. The thermal stability of the composite gel was improved by the participation of KGM. FTIR analysis showed that the interactions were mainly related to intermolecular hydrogen bonds and acetyl groups. The microscopic morphology of KGM4 was significantly continuous, smooth, and compact, exhibiting the best practical performance and taking the maximum advantage.

Purification, Structural Characterization, and Antitumor Activity of a Polysaccharide from Perilla Seeds.

A previous study found that a crude Perilla seed polysaccharide (PFSP) fraction exhibited obviously antitumor activity; however, the structural characterization and antitumor properties of this polysaccharide remain unclear. In this study, the PFSP was extracted and purified via combined column chromatography, and the structure of a single polysaccharide fraction was characterized by methylation, IC, GC-MS, NMR, and AFM. The results demonstrated that the efficient antitumor polysaccharide fraction PFSP-2-1 was screened from PFSP with a relative molecular weight of 8.81 × 106 Da. The primary structure of the PFSP main chain was →1)-Araf-(5→, →1,3)-Galp-(6→, →1)-Galp-(6→, →1,3)-Araf-(5→ and →1)-Xylp-(4→, and that of the side chains was →1)-Arap, →1,3)-Galp-(6→, →1)-Araf and →1)-Glcp-(4→, →1)-Galp-(3→ and →1)-Glcp, leading to a three-dimensional helical structure. CCK-8 experiments revealed that PFSP-2-1 significantly inhibited the growth of human hepatocellular carcinoma cells in vitro (p < 0.05), and its inhibitory effect positively correlation with the concentration of PFSP-2-1, and when the concentration of PFSP-2-1 was 1600 µg/mL, it showed the highest inhabitation rate on three hepatocellular carcinoma cells (HepG-2, Hep3b, and SK-Hep-1), for which the survival rates of HepG-2, Hep3b, and SK-Hep-1 were 53.34%, 70.33%, and 71.06%. This study clearly elucidated the structure and antitumor activity of PFSP-2-1, which lays a theoretical foundation for revealing the molecular mechanism of antitumor activity of Perilla seed polysaccharides and provides an important theoretical basis for the development of high-value Perilla.

Ameliorating the stability of native/thermally denatured chicken-derived myofibrillar proteins particles in an aqueous system: The synergistic effect of acidification combined with inulin and inulin/sodium alginate

The effect of acidification through hydrochloric acid combined with inulin (In), and inulin/sodium alginate (In/SA) on the stability of native/thermally denatured myofibrillar proteins (MPs/TMPs) particles in an aqueous system was investigated. At the same pH, MPs-In and TMPs-In particles were smaller and had higher absolute potentials than MPs-In/SA and TMPs-In/SA particles. Additionally, the size of MPs-In particles reached 1 μm, and the solubility increased from 21.73 ± 0.57 % to 76.26 ± 1.27 % when the pH was reduced from 5.0 to 3.0. The absolute potential of TMPs 3-In particles increased from 15.77 ± 0.72 to 28.20 ± 0.30 mV, and the solubility increased from 18.65 ± 0.72 % to 74.53 ± 0.74 %. Confocal laser microscopy revealed that, compared with pH 5.0 or 4.0, MPs-In/TMPs-In particles dispersed more evenly at pH 3.0 compared with pH 5.0 or 4.0. This further confirmed that electrostatic repulsion between particles maximally contributed to particle stability. Furthermore, the α-helix content in TMPs-In particles at pH 3.0 decreased from 41.51 ± 1.09 % (TMPs control) to 16.61 ± 1.87 %. This decrement of an up to 60 % led to decreased intramolecular hydrogen bonds and improved surface hydrophobicity. Therefore, a single polysaccharide (In) combined with MPs/TMPs particles exhibited higher dispersion and stability at pH 3.0. These findings could provide new insights into chicken-derived protein beverage processing.

Key role of three-dimensional reticular interface membranes in the formation of single polysaccharide–stabilized high internal phase emulsions

Although the interfacial activity of polysaccharides is believed to be insufficient for their applications as individual emulsifying stabilizers, four single polysaccharides examined herein, namely sodium carboxymethyl cellulose (Na-CMC), sodium alginate (SA), high-methoxyl pectin (HMP), and low-methoxyl pectin (LMP) are shown to effectively stabilize high internal phase emulsions (HIPEs) at loadings as low as 0.1 wt% under acidic conditions, that is, at pH 0.5–5.2 (Na-CMC), 0.5–4.0 (SA), 1.0–4.2 (HMP), and 1.0–3.0 (LMP). Despite their structural differences, the four studied polysaccharides feature similar HIPE stabilization mechanisms that mainly involve the formation of three-dimensional reticular interface membrane structures with fiber branching chains. Within the pH range suitable for HIPE formation, the polysaccharides mainly exist as nanofiber network structures with a grid width of 50–100 nm but adopt flake-like and other structures at higher pH. Further insights are provided by the relationship between network membrane structures formed at the interface and the fiber network structures formed by polysaccharides in the original aqueous phase. In addition, the inferred emulsification and stabilization mechanisms are shown to be significantly different from those observed for mainstream Pickering HIPE stabilizers. Thus, our work expands the understanding of the interfacial activity function of polysaccharides, provides conceptual thinking reference and design rules for the development of simple, efficient, safe, and cheap polysaccharide-based HIPEs, and supplements and furthers the theory of HIPE stabilization.

Helicity degree of carrageenan conformation determines the polysaccharide and water interactions

The polysaccharide in solution at critical concentration, Cc (g/L), is assimilated to a nano hydrogel (nHG) made of a single polysaccharide chain. Taking as reference the characteristic temperature of 20 ± 2 °C at which kappa-carrageenan (κ-Car) nHG swelling is greater with a Cc = 0.55 ± 0.05 g/L, the temperature of the minimum deswelling in the presence of KCl was found at 30 ± 2 °C for 5 mM with a Cc = 1.15 ± 0.05 g/L but not measurable above 100 °C for 10 mM of which Cc = 1.3 ± 0.05 g/L. Lowering the temperature to 5 °C, contraction of the nHG and further coil-helix transition with self-assembly increases the sample's viscosity, which steadily evolves with time in a logarithmic scale. Accordingly, the relative increment of the viscosity per unit of concentration, Rv (L/g), should increase in agreement with increasing polysaccharide concentration. But the Rv decreases for κ-Car samples above 3.5 ± 0.5 g/L in the presence of 10 mM KCl under steady shear 15 s−1. This reflects a decrease of κ-Car helicity degree knowing that the polysaccharide is rather hydrophilic when its helicity degree is the lowest.

Effect of synergism between sodium alginate and xanthan gum on characteristics of composite film and gloss of areca nut coating

In this study, two polysaccharides of sodium alginate (SA) and xanthan gum (XG) were compounded in proportions of 100:0, 75:25, 50:50, 25:75, 0:100 with 1% total mass concentration and then coated on areca nuts. The effects of their synergistic interactions on the optical appearance of the edible coating were investigated for the first time. Areca nuts coated by 50:50 SA-XG presented the highest gloss (2.69 GU) and maximum spreading coefficient (−33.95 mN/m), indicating the improved wettability of the coating solution on the fruit's surface. The polarized light microscopy exhibited the unique birefringence phenomenon caused by the liquid crystal state, resulting in the better optical properties of the coating. UV–vis transmittance, Fourier transform infrared, and scanning electron microscopy indicated the good compatibility of SA and XG. The SA-XG film was more compactly arranged and had a denser microstructure due to hydrogen bonding. Additionally, the SA-XG combination improved the mechanical properties and water resistance compared to a single polysaccharide films and enhanced the water retention properties for the areca nut coating. Therefore, the SA-XG combination is promising to prepare edible films with improved optical properties for areca nuts.

Insights into the Role of Natural Polysaccharide-Based Hydrogel Wound Dressings in Biomedical Applications.

Acute skin damage caused by burns or cuts occurs frequently in people’s daily lives. Such wounds are difficult to heal normally and have persistent inflammation. Wound dressings not only improve the speed of wound healing, but also protect and cover the wound well. Hydrogels have the characteristics of good flexibility, high water content, and good biocompatibility, and are widely used in biomedicine and other fields. Common hydrogels are mainly natural hydrogels and synthetic hydrogels. Hydrogels cross-linked using different raw materials and different methods have different performance characteristics. Natural hydrogels prepared using polysaccharides are simple to obtain and have good biocompatibility, but are inferior to synthetic hydrogels in terms of mechanical properties and stability, and a single polysaccharide hydrogel cannot meet the component requirements for wound healing. Therefore, functional composite hydrogels with high mechanical properties, high biocompatibility, and high antibacterial properties are the current research hotspots. In this review, several common polysaccharides for hydrogel synthesis and the synthesis methods of polysaccharide hydrogels are introduced, and functional composite hydrogel dressings from recent years are classified. It is hoped that this can provide useful references for relevant research in this field.

Silymarin-Encapsulated Xanthan Gum-Stabilized Selenium Nanocarriers for Enhanced Activity Against Amyloid Fibril Cytotoxicity.

The accumulation of amyloid-beta at the neuronal sites is a major pathological hallmark involved in the etiology of Alzheimer's disease. To reduce the Aβ-induced neuronal cytotoxicity, selenium nanoparticles and silymarin were fabricated in a single polysaccharide matrix for dual antioxidant and Aβ fibril disaggregation activity. These nanoparticles were further stabilized by an exopolysaccharide xanthan gum. The nanoparticles were fabricated to reduce the amyloid-induced cytotoxicity in SH-SY5Y cells. A three-step method employing redox reaction of sodium selenite and ascorbic acid has been adopted for the synthesis of selenium nanoparticles. Consequently, xanthan gum powder was added to impart stability to the nanocarriers. The nanoparticles exhibited a particle size of 119.2 ± 2.8nm, zeta potential of - 35.4 ± 3.8mV, and % EE of 87.7 ± 2.23. HR-TEM with EDX analysis confirmed the presence of spherical nanoparticles. An in vitro drug release study exhibited 89.33 ± 5.4% release of silymarin from nanocarriers and was able to scavenge 90% free radicals of DPPH reagent. The thioflavin T (ThT) fibrillation kinetics study showed that the nanoparticles elicited maximum disaggregation of Aβ fibrils that was depicted by the quenched fluorescence intensity signal. The cell viability results revealed that the highest neuroprotection activity was observed in the cell group treated with SLY-XG-Se against Aβ 1-42-induced toxicity. The nanoparticles were able to internalize in SH-SY5Y cells. Our findings showed that the nanocarrier elicited anti-aggregation efficacy in neuronal cell lines and mitigated the Aβ-induced cytotoxicity, which represents the prospects of neuroprotection involved in the therapeutics of AD.

Scale-up issues during sterile filtration of glycoconjugate vaccines.

Several recent studies have provided important insights into the factors controlling the sterile filtration of glycoconjugate vaccines; however, this work has been limited to small-scale disk filters with very uniform flow distribution. The objective of this study was to examine the scale-up of the sterile filtration step using a glycoconjugate drug substance made from a single polysaccharide serotype. Experimental data were obtained during constant flux filtration through 0.22 μm Durapore® polyvinylidene difluoride (PVDF) membranes, both with small discs and with the Opticap® XL2 pleated cartridge. The transmembrane pressure increased rapidly during the glycoconjugate filtration due to membrane fouling, with the rate of pressure increase being more pronounced in the pleated cartridge. Additional insights into the fouling behavior were obtained using confocal microscopy by in situ labeling of the glycoconjugate captured within the filter media using an Alexa Fluor fluorescent dye. Glycoconjugate deposition occurred only within the first 5-15 μm of the 0.22 μm Durapore® membrane at both scales, with more variability in the deposition pattern observed for the pleated filter due to the non-uniform flow distribution in the Opticap® XL2 cartridge. These results provide important insights into the underlying fouling behavior during sterile filtration of glycoconjugate vaccines as well as a framework for the scale-up of the sterile filter step in glycoconjugate biomanufacturing.

Two colorimetric films based on chitin whiskers and sodium alginate/gelatin incorporated with anthocyanins for monitoring food freshness

Intelligent food packaging materials from natural resources has attracted increasing attention nowadays. In this paper, two fresh colorimetric films were obtained by incorporating natural pigment anthocyanins extract (LRM) as pH-sensitive pigments into two polyelectrolyte complex films composed of chitin whiskers (CW) and sodium alginate (SA)/gelatin (GE), respectively. The analysis results of FTIR, SEM and DSC show that, compared with the single polysaccharide system of SA or GE, the composite film with addition of CW has better water resistance and thermal stability, due to the existence of hydrogen bonds and electrostatic interactions. Meanwhile, the adhesion to LRM is also enhanced. At the same time, through Ritger–Peppas kinetic model analysis, the release process of anthocyanins in the two film systems was analyzed. The CW/SA/LRM system membrane showed good responsiveness to lactic acid and was successfully used in the detection of milk freshness; while the CW/GE/LRM system membrane showed good responsiveness to amine gases and has been successfully used in the detection of pork freshness. The study revealed that the above colorimetric films demonstrate excellent durability and accuracy in food freshness monitoring.

Preparation and properties of triethyl citrate plasticized chitosan‐based membranes for efficient release of curcumin

AbstractIn order to improve the release efficiency and physical properties of single polysaccharide membranes, two types of curcumin (Cur)‐loaded composite membranes have been successfully prepared through chitosan (CS)/carboxymethyl cellulose (CMC), CS/soluble starch (SS) with triethyl citrate (TEC) as a plasticizer. The structure and properties of the membranes were characterized by infrared spectroscopy, scanning electron microscopy, X‐ray diffraction, and thermogravimetry. The results of mechanical tests and drug release experiments show that TEC changes the intermolecular forces in the membrane matrix, makes the membrane more flexible and increases the cumulative release rate of curcumin. The cumulative release rate of Cur in CS/CMC‐Cur and the CS/SS‐Cur membrane can reach 86.5% and 87.3% at 24 h, respectively. Cur release in CS/CMC‐Cur followed the irregular Fickian diffusion behavior, whereas in CS/SS‐Cur followed the non‐Fickian diffusion behavior. The prepared composite membrane performs good thermal stability, tensile resistance and strong inhibitory effect on Escherichia coli.

Subcellular coordination of plant cell wall synthesis.

Organelles of the plant cell cooperate to synthesize and secrete a strong yet flexible polysaccharide-based extracellular matrix: the cell wall. Cell wall composition varies among plant species, across cell types within a plant, within different regions of a single cell wall, and in response to intrinsic or extrinsic signals. This diversity in cell wall makeup is underpinned by common cellular mechanisms for cell wall production. Cellulose synthase complexes function at the plasma membrane and deposit their product into the cell wall. Matrix polysaccharides are synthesized by a multitude of glycosyltransferases in hundreds of mobile Golgi stacks, and an extensive set of vesicle trafficking proteins govern secretion to the cell wall. In this review, we discuss the different subcellular locations at which cell wall synthesis occurs, review the molecular mechanisms that control cell wall biosynthesis, and examine how these are regulated in response to different perturbations to maintain cell wall homeostasis.

Hydrogel Beads of Natural Polymers as a Potential Vehicle for Colon-Targeted Drug Delivery.

Polysaccharides are excellent candidates for drug delivery applications as they are available in abundance from natural sources. Polysaccharides such as starch, cellulose, lignin, chitosan, alginate, and tragacanth gum are used to make hydrogels beads. Hydrogels beads are three-dimensional, cross-linked networks of hydrophilic polymers formed in spherical shape and sized in the range of 0.5-1.0mm of diameter. Beads are formed by various cross-linking methods such as chemical and irradiation methods. Natural polymer-based hydrogels are biocompatible and biodegradable and have inherently low immunogenicity, which makes them suitable for physiological drug delivery approaches. The cross-linked polysaccharide-based hydrogels are environment-sensitive polymers that can potentially be used for the development of "smart" delivery systems, which are capable of control release of the encapsulated drug at a targeted colon site. This topic focuses on various aspects of fabricating and optimizing the cross-linking of polysaccharides, either by a single polysaccharide or mixtures and also natural-synthetic hybrids to produce polymer-based hydrogel vehicles for colon-targeted drug delivery.

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.

Glucose- lowering effect of Trametes orientalis polysaccharides in hyperglycemic and hyperlipidemic mice

To explore the glucose-lowering effect of the polysaccharide fractions of Trametes orientalis. The crude polysaccharides of T. orientalis were chromatographed on DEAE cellulose column using H2O and 0.5 mol/L NaCl solution as the eluent and DEAE-water and DEAE-salt with high polysaccharide contents were collected. The two fractions were separated using Sephadex G-100 gel column to obtain 4 polysaccharide fractions TOPW-1, TOPW-2, TOPS-1, and TOPS-2. The anti-oxidation activity of the polysaccharide fractions was investigated with ABTS method. The fractions TOPW-1 and TOPS-1 with consistent UV detection signals were collected and HPGPC was used to determine their relative molecular mass. The monosaccharide composition in homogeneous TOPW-1 was determined by acid hydrolysis combined with HPLC. The in vitro inhibitory activities of TOPW-1 and TOPS-1 against DPP4, adipocyte glucose intake and lipase activity were tested to preliminarily assess their glucose-lowering effect. In a mouse model of hyperglycemic and hyperlipidemic, the glucose-lowering effect of TOPS-1 (0.1, 0.2, and 0.4 g/kg) and its effect on blood lipid metabolism were investigated in comparison with Xiaoke pills (5 pills/kg) and Danshen tablets (0.5 g/kg). TOPW-1 was a homogeneous polysaccharide composed mainly of D-mannose, D-glucose, D-galactose, and D-fucose, with weak antioxidant and hypoglycemic effects. TOPS-1 was not a single polysaccharide and at the concentration of 500 μg/mL showed an high ABTS clearance rate (90.15%). In the mouse model of hyperglycemia and hyperlipidemia, treatment with TOPS-1 (0.2 g/kg) enhanced the activity of lipase and significantly reduced fasting glucose level and serum contents of total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol without causing death in the mice. The glucose-lowering effects of TOPS-1 was not significant at the low (0.1 g/kg) or high (0.4 g/kg) dose, and a high dose tended to increase the mortality of the mice. T. orientalis polysaccharides have anti-oxidation, glucose-lowering and lipid-lowering effects in mice, and their glucose-lowering effect is probably medicated by reducing oxidative stress and ameliorating lipid metabolism disorder.

Formation of Higher Structural Levels in λ-Carrageenan Induced by the Antimalarial Drug Chloroquine.

The linear polysaccharide λ-carrageenan is the only one among the carrageenans not forming secondary, tertiary, and quaternary structures in the presence of inorganic ions. Chloroquine (CQ) is a well-established antimalaria drug also recently discussed in therapeutics against the COVID-19 pandemic. The interaction of this polysaccharide-ionic drug pair was investigated by combining UV-vis spectrophotometry and atomic force microscopy (AFM) imaging. A decrease of the UV peak assigned to free CQ and the occurrence of isosbestic points indicate the formation of complexes. High-resolution AFM height images revealed an increasing height of the single polysaccharide chains in the random coil state upon addition of CQ, indicating the formation of a secondary structure, followed by higher hierarchical aggregates. The disappearance of higher-ordered structures and the recovery of polysaccharide chains with primary structure were observed by introducing inorganic cations (Na+, K+, Ca2+), replacing the condensed CQ and paving the way to reversible ion-induced drug release.

Polysaccharide Structures in the Outer Mucilage of Arabidopsis Seeds Visualized by AFM.

Evidence is presented that the polysaccharide rhamnogalacturonan I (RGI) can be biosynthesized in remarkably organized branched configurations and surprisingly long versions and can self-assemble into a plethora of structures. AFM imaging has been applied to study the outer mucilage obtained from wild-type (WT) and mutant (bxl1-3 and cesa5-1) Arabidopsis thaliana seeds. For WT mucilage, ordered, multichain structures of the polysaccharide RGI were observed, with a helical twist visible in favorable circumstances. Molecular dynamics (MD) simulations demonstrated the stability of several possible multichain complexes and the possibility of twisted fibril formation. For bxl1-3 seeds, the imaged polymers clearly showed the presence of side chains. These were surprisingly regular and well organized with an average length of ∼100 nm and a spacing of ∼50 nm. The heights of the side chains imaged were suggestive of single polysaccharide chains, while the backbone was on average 4 times this height and showed regular height variations along its length consistent with models of multichain fibrils examined in MD. Finally, in mucilage extracts from cesa5-1 seeds, a minor population of chains in excess of 30 μm long was observed.

Isolation, Purification and Antioxidant Activity of The Polysaccharides from Chinese Truffle Tuber sinense.

The content of polysaccharides in Tuber sinense was investigated by isolation and purification, followed with the further antioxidant studies in total reducing capacity and radical scavenging activities. The crude extract of polysaccharides was purified by dialysis, column chromatography, and High Performance Liquid Chromatography. The main components of monosaccharide (s) and molecular structure of single polysaccharide were studied by using methylation, GC-MS, and NMR analysis. One new water-soluble non-starch polysaccharide (PTS-A with the yield of 0.41%) from T. sinense was purified and identified on structural characteristics for the first time. The characterizations of PTS-A were studied on physicochemical properties, main components of monosaccharide (s) and molecular structure. PTS-A was identified as glucan, only containing D-glucoses with the molecular structure of [→6) α-D-Glcp (1→6) α-D-Glcp (1→]n by methylation analysis and NMR. In the determination of total reducing capacity, their reducing abilities could be listed as vitamin C> PTS-A> crude polysaccharides-3> crude polysaccharides-2> crude polysaccharides-1. All of PTS-A, crude polysaccharides-2 and -3 were relatively good scavenger for 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1- (2,4,6-trinitrophenyl) hydrazyl radicals with the IC50 of 2.81, 4.17 and 3.44 mg/mL, respectively. Thus, the separation and purification of polysaccharides were significant to increase the antioxidant activity in some degree. One new water-soluble 1,6-α-ᴅ-dextran was discovered with the polysaccharide structure identified for the first time. Both PTS-A and crude extracts of polysaccharide performed a potent potential on antioxidant activities. The bioactivities of PTS-A should be generalized to the broader pharmacological effects.