Characterisation, Chain Conformation and Antifatigue Effect of Steamed Ginseng Polysaccharides With Different Molecular Weight

Two polysaccharides were obtained from steamed ginseng via ultrafiltration, and their physical–chemical properties, solution properties and antifatigue activities were studied. WSGP-S3 and WSGP-G3 were acid heteropolysaccharides with the molecular weights of 2.03 × 104 and 4.86 × 104, respectively. They were composed of different molar ratios of the monosaccharides Rha, GlcA, GalA, Glc, Gal, and Ara. The results of size-exclusion chromatography–multiangle laser light scattering analysis, Conge red staining and Circular dichroism spectroscopy revealed that WSGP-S3 exhibited a random conformation of branched clusters in solution. By contrast, WSGP-G3 exhibited an ordered conformation, including helix-like conformations in aqueous solution. Antifatigue activity tests proved that WSGP-S3 markedly prolonged the exhaustive swimming time of fatigued mice; increased liver and muscle glycogen levels and superoxide dismutase, catalase, glutathione peroxidase activities and decreased blood lactic acid, nitrogen and malondialdehyde levels compared with the control treatment. Moreover, it enhanced spleen cell proliferation in fatigued mice. By contrast, WSGP-G3 had no significant effect on fatigued mice. The results showed that WSGP-S3 might have a major contribution to the antifatigue effects of steamed ginseng polysaccharides and could be a potential anti-fatigue polysaccharide.

Synthesis of Silver and Gold Nanoparticles in Sodium Alginate Matrix Enriched with Graphene Oxide and Investigation of Properties of the Obtained Thin Films

Polymer nanocomposites containing nanometals became a subject of interest due to their bactericidal properties. Different polysaccharides have been used as matrices for nanosilver and nanogold synthesis. In this study, we present a novel, environmentally friendly method for the preparation of sodium alginate/nanosilver/graphene oxide (GOX) and sodium alginate/nanogold/graphene oxide GOX nanocomposites and their characteristics. The formation of approximately 10–20 nm ball-shaped Ag and Au nanoparticles was confirmed by UV–vis spectroscopy, scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectra. The incorporation of GOX sheets within the ALG matrix improved the thermal stability of the nanocomposites film, which was measured using the differential scanning calorimetry (DSC). We also estimated the molecular weights of polysaccharide chains of the matrix with the size exclusion chromatography coupled with multiangle laser light scattering and refractometric detectors (HPSEC-MALLS-RI). The composites were more prone to enzymatic hydrolysis. The strongest bacteriostatic activity was observed for the sample containing nanosilver.

Multiscale Structure of Starches Grafted with Hydrophobic Groups: A New Analytical Strategy

Starch, an abundant and low-cost plant-based glucopolymer, has great potential to replace carbon-based polymers in various materials. In order to optimize its functional properties for bioplastics applications chemical groups need to be introduced on the free hydroxyl groups in a controlled manner, so an understanding of the resulting structure-properties relationships is therefore essential. The purpose of this work was to study the multiscale structure of highly-acetylated (degree of substitution, 0.4 < DS ≤ 3) and etherified starches by using an original combination of experimental strategies and methodologies. The molecular structure and substituents repartition were investigated by developing new sample preparation strategies for specific analysis including Asymmetrical Flow Field Flow Fractionation associated with Multiangle Laser Light Scattering, Nuclear Magnetic Resonance (NMR), Raman and Time of Flight Secondary Ion Mass spectroscopies. Molar mass decrease and specific ways of chain breakage due to modification were pointed out and are correlated to the amylose content. The amorphous structuration was revealed by solid-state NMR. This original broad analytical approach allowed for the first time a large characterization of highly-acetylated starches insoluble in aqueous solvents. This strategy, then applied to characterize etherified starches, opens the way to correlate the structure to the properties of such insoluble starch-based materials.

Evaluation of charged molecules content of plant polysaccharides by aqueous size exclusion chromatography

Aqueous size-exclusion chromatography (SEC) equipped with refractive index (RI) and multiangle laser light scattering (MALLS) detectors were applied to evaluation of charged molecules content in a series of polysaccharide derivatives with different average molar mass (MM) values. It was shown that a minor amount of residual charged groups in the polysaccharide chains caused a polyelectrolyte expansion effect and neutral fractions of birch xylans, larch arabinogalactans (AG) and galactoglucomannans (GGM) were separated from neutral molecules in various concentrations of the injected samples

Molecular and Supramolecular Changes in Polybutylene Succinate (PBS) and Polybutylene Succinate Adipate (PBSA) Copolymer during Degradation in Various Environmental Conditions

In this paper, the influence of the various degradation conditions, on the molecular and supramolecular structure of polybutylene succinate (PBS) and polybutylene succinate adipate (PBSA) copolymer during degradation time is described. Experiment was carried out by the use injection molded samples and normalized conditions of biodegradation in soil, composting and artificial weathering. Materials were studied by using size-exclusion chromatography (SEC) coupled with multiangle laser light scattering (MALLS) detection and wide-angle X-ray diffraction (WAXD). Additionally, the physical and mechanical properties of the samples were determined. The performed experiments clearly show difference impact of selected degradation condition on the macroscopic, supramolecular and molecular parameters of studied aliphatic polyesters. The structural changes in PBS and PBSA explain the observed changes in the physical and mechanical properties of the obtained injection molded samples.

Solubility Behaviour of Cellulose Acetate Butyrate in Mixture of Solvents

In order to identify the proper solvent mixture for future processing from solution of cellulose derivatives, the laser light scattering method was used. The multiangle laser light scattering parameters of macromolecular chains in solution (weight-average molecular weigh , radius of gyration Rg and second virial coefficient A2) were correlated with the values of dielectric constant of solvent mixture (2-methoxyethanol + N,N-dimethylformamide). The experimental results revealed that the protic solvent favored the extended conformation of the macromolecules in solution, necessary condition to obtaine nanofibers by electrospinning.

Influence of the homehold composting conditions on the structural changes of polylactide spun-bonded nonwovens during degradation

In this study, the influence of homehold composting conditions on the molecular and supramolecular structure of polylactide (PLA) in the form of spun-bonded nonwovens was investigated. Nonwoven samples were studied using size-exclusion chromatography coupled with multiangle laser light scattering detection, wide-angle X-ray diffraction, differential scanning calorimetry and Fourier transform infrared spectroscopy. In addition, the physical and mechanical properties of the nonwovens before and after composting were determined. The results show the varying degree of influence of the prepared compost mixtures of soil with common horticultural additives, such as chalk, commercially available agents, cow manure and chicken litter, on the molecular and supramolecular structure of PLA and its degradation rate. The obtained experiment explained which popular homehold agent had the strongest affect on the PLA nonwoven dedicated for agriculture use in the first period of season composting (first 6 months).