Rheological Properties Of Polysaccharide Research Articles

Rheological properties of polysaccharides from Pholiota nameko with different temperature extraction: Concentration, pH, temperature, and saltion.

Cold and hot water extracted polysaccharides (CW-PNPs and HW-PNPs) were isolated from Pholiota nameko. The rheological properties of PNPs were investigated by steady shear and oscillatory rheological measurements. The PNPs exhibited typical non-Newtonian and shear-thinning behavior, which are affected by PNP concentration, temperature, pH value, salt ion, and concentration. Specifically, the apparent viscosity of the two PNPs solutions at concentration of 1% (w/w) was shown as HW-PNPs>CW-PNPs. The apparent viscosity of PNPs decreases under acidic and alkaline conditions and when the temperature rises; K+ and Na+ cause the apparent viscosity of CW-PNPs to decrease, while Ca2+ and Al3+ are opposite. The addition of four different salt ions all caused the apparent viscosity of the HW-PNPs to decrease. The results of dynamic rheological experiments show that G' and G″ showed slightly frequency dependency with G' exceeding G″ throughout the accessible range of frequency for CW-PNPs and HW-PNPs.

Effect of Calcium on the Rheological Properties of Polysaccharide from Abelmoschus Esculentus (Okra) Pod and its Application of Coating Preservation Technique for Postharvest Annona Squamosa

Effect of Calcium on the Rheological Properties of Polysaccharide from Abelmoschus Esculentus (Okra) Pod and its Application of Coating Preservation Technique for Postharvest Annona Squamosa

Rheological aspects of polysaccharides

The material structure which is formed in the manufacturing process of products with tailored properties governs the viscoelastic behavior of polymeric materials, and consequently determines the functionality of products made of polysaccharides. The mechanical (rheological) properties of these biopolymers reflect their time- and frequency-dependent behavior, and therefore, its determination represents the reliable instrument to study correlation between structure formation and rheological properties of polysaccharides. Three microbial extracellular polysaccharides, i.e., gellan, welan and xanthan, and two water-soluble cellulose derivatives, i.e., carboxymethylcellulose (CMC) and hydroxypropylmethylcellulose (HPMC) were examined by using frequency and creep-recovery tests. The resulted shear dynamic moduli demonstrated differences in viscoelastic behavior of the examined polysaccharides. For gellan samples differences in response at different stages of aging were observed, indicating that aging considerably influences the structure changes of water-based gellan systems.

Polysaccharides from the lignified okra: Physicochemical properties and rheological properties

In this paper, the polysaccharides were extracted and isolated from the lignified okra for the first time. Three fractions AP1, AP2 and AP3 were obtained. Further, the physicochemical and rheological properties of polysaccharides were investigated. Components analysis indicated that AP1, AP2 and AP3 were consisted of glucose, xylose, mannose, arabinose, rhamnose and galactose with different molar ratios. The molecular weights of three components were 6.69 × 105 Da, 2.50 × 105 Da and 1.79 × 105 Da, respectively. AP3 had the largest content of uronic acid (46.63%), while AP1 had the lowest content (29.99%). Three-stage mass loss patterns were observed in the curves of thermal gravimetric. AP1, AP2 and AP3 were relatively stable and had good thermal stability under 200 °C. Rheological analysis indicated that three fractions exhibited pseudoplasticity fluid behaviors. AP3 exhibited stronger shear-thinning property and a more stable flow behavior than the others. AP2 and AP3 showed strong elastic gel-like behavior (G' > G″), while AP1 performed the sol-gel transition at high concentration. The rheological properties were closely related to the chemical composition. These results provided a valuable data basis for the utilization of the lignified okra.

Effects of deproteinization on rheological properties of polysaccharides from Rosa acicularis ‘Lu He’ and Rosa acicularis Lindl fruits

Polysaccharides from the fruits of Rosa acicularis are one of the main functional components with superior biological activities and physicochemical properties. Rosa acicularis 'Lu He' is a new variety derived from the wild type Rosa acicularis Lindl. A comparative study was performed on the chemical composition and rheological properties of polysaccharides of rosehip from Rosa acicularis 'Lu He' (RLHP) and Rosa acicularis Lindl (RLDP) before and after deproteinization. The polysaccharide extracts, regardless of deproteinization, were acidic heteropolysaccharides composed of 48.3–51.6% carbohydrate and 29.2–43.2% uronic acid on dry weight basis and small amounts of protein (1.8–6.2%) and polyphenol (2.1–6.3%). Steady shear and frequency scanning measurements were used to evaluate the changes in concentration, temperature, pH and salts on the apparent viscosity and dynamic viscoelasticity of polysaccharide of rosehip solutions. The results showed that the apparent viscosity of RLHP was higher than that of RLDP at the same concentrations (2–6%), while apparent viscosity of RLHP and RLDP increased by 7.2% and 20.5% after deproteinization, respectively. Solutions of polysaccharide of rosehip exhibited shear-thinning behaviors, and higher concentrations caused more significant pseudoplastic effects. The solution properties changed from pseudoplasticity to plasticity when the initial apparent viscosity was below 7.5 mPa s. Thixotropy of polysaccharides of rosehips was stronger after protein removal; moreover, the polysaccharides before deproteinization (RLHP-1, RLDP-1) exhibited better gel properties than the deproteinized polysaccharides (RLHP-2, RLDP-2). This rheological property information will help proper product design to ensure the stability of food products enhanced with polysaccharides from rosehips.

The assembly and antitumor activity of lycium barbarum polysaccharide-platinum-based conjugates

In this work, the new polysaccharide-platinum conjugates of 5-aminosalicylic acid modified lycium barbarum polysaccharide linking platinum compounds were designed in order to construct an anticancer metal drug delivery system. The multiple analysis methods were used to describe the chemical structure and physical properties of the polysaccharide-metal conjugates. The results showed that 5-aminosalicylic acid successfully acted as linker which was covalently bound between polysaccharide and platinum compound. The morphology and rheological properties of polysaccharide have been changed by the formation of conjugates, which exhibited certain inhibition specificity to A549 (human lung cancer cell line). The agarose gel electrophoresis and fluorescence microscopy results demonstrated that such conjugates promoted the unwinding of DNA and could significantly damage the nucleus of A549 cells. Cell cycle analyzing the Pt complex of conjugates could cause intracellular DNA damage and induced G2 phase arrest. So, polysaccharide-platinum conjugates might find a range of applications, for example in metal anticancer drug delivery.

Optimization of Ultrasonic/Microwave Assisted Extraction (UMAE) and Rheological Properties of Polysaccharides from Auricularia polytricha

Polysaccharides from Auricularia polytricha (APPS) were extracted using Ultrasonic/Microwave Assisted Extraction (UMAE) technology. UMAE conditions of APPS were optimized with Response Surface Methodology (RSM). Rheological properties of APPS were investigated. The results suggested that the optimal UMAE conditions for APPS were ratio of water to raw material 22 (mL/g), extraction time 15.3 min and microwave power 59W. APPS solution exhibited Newtonian flow behavior at low concentration, formed entanglement network at lower concentration and established weak gel structures with solid-like properties at higher concentration. The viscosity of APPS solutions decreased when temperature increased. The viscosity, storage (G') and loss (G") modulus of APPS solution increased when sucrose concentration increased. Heating time and freeze-thaw changes had no significant effect on rheological properties of APPS. The results suggested that UMAE was a suitable and efficient method for APPS extraction and APPS had potential as a novel food additive hydrocolloid in food industry.

The influence of extraction pH on the chemical compositions, macromolecular characteristics, and rheological properties of polysaccharide: The case of okra polysaccharide

Extraction pH plays an essential role in influencing the characteristics and functions of polysaccharides. However, the systematic study on the influence under a broad range and diverse gradient of pH is limited. In this study, polysaccharides from okra pods (Abelmoschus esculentus L.) were prepared using six extraction solutions with pH of 2.0, 4.0, 5.7, 8.0, 10.0, and 12.0. Physicochemical properties of the okra polysaccharides were then investigated. The respective results of the yield, protein content, total carbohydrate content, and degree of esterification of the polysaccharide samples were in the range of 7.68–20.15%, 1.38–3.79%, 67.86–88.77%, and 56.42–73.85% depending on the extraction pH. All polysaccharide samples, with a RG-I pectic structure subunit, were mainly composed of galactose, galacturonic acid, rhamnose, glucose, and arabinose. The molar ratio of the monosaccharides varied depending on the extraction pH and the side chain length of the RG-I backbone for acidic-extracted polysaccharides was larger than that for alkaline-extracted polysaccharides. In addition, the molecular weight increased with increasing extraction pH under acidic extraction conditions, whereas decreased when the pH rose to the alkaline range. Furthermore, rheological measurements revealed that all polysaccharide samples behaved as pseudoplastic fluids over a range of shear rates (0.1–100 s−1) and exhibited different viscosity and viscoelastic behaviors due to the variation in chemical compositions and macromolecular characteristics. The results indicate that the preparation of polysaccharides with specific characteristics and functions could be controlled by adjusting extraction pH.

Rheological behaviors of microbial polysaccharides with different substituents in aqueous solutions: Effects of concentration, temperature, inorganic salt and surfactant

Rheological behaviors of microbial polysaccharides with different substituents in aqueous solutions have been systematically investigated. Both the saccharide side chains and acetyl substituents improve the gelation of welan gum (WG), diutan gum (DG) and gellan gum (GG) in pure water at 25 °C. For the polysaccharides with saccharide side chains (WG and DG), the relationship between the apparent viscosity and concentration conforms to the linear equation, while that of the polysaccharide with acetyl (GG) is exponential. More importantly, the roles of substituents on the stability of the molecular conformation of polysaccharides are significantly depended on the surrounding environment. Disaccharide side chains promote the stability of helical conformation and gel aggregates of GG at high temperature (85 °C) or in the presence of inorganic salts with the ionic strength of 2.0 mol L−1. The stability of gel structure containing acetyl (GG) shows higher temperature/salt sensitivity. Additionally, deacylated gellan gum (GG(d)) solutions transform into hydrogels in the presence of dodecyltrimethylammonium bromide (DTAB). This study will help to obtain a better understanding on the rheological properties of polysaccharides with respect to the conformation and applications.

Effects of Ultrasound Treatment on Extraction and Rheological Properties of Polysaccharides from Auricularia Cornea var. Li.

Auricularia cornea var. Li. is an edible fungi and polysaccharides in Auricularia cornea var. Li. may have bioactive activities. Polysaccharides from Auricularia cornea var. Li. (ACP) was extracted using ultrasound-assisted extraction (UAE) method and compared with hot water extraction (HWE) for extraction yield, extraction rate, purity of polysaccharides, microstructure of residues after extraction, preliminary structure and rheological properties of polysaccharides. Optimum conditions for UAE (particle size of 150–200 mesh, water to raw material ratio of 70:1, extraction temperature at 70 °C for 40 min, ultrasonic amplitude of 40%) and HWE (particle size of 150–200 mesh, water to raw material ratio of 60:1, extraction temperature at 90 °C for 3.0 h) were obtained via single-factor experiment. Under optimum conditions, extraction yield of polysaccharides by UAE was 30.99 ± 1.93% which showed no significant difference with that by HWE (30.35 ± 1.67%) (P > 0.05). Extraction rate (29.29 ± 1.41%) and purity (88.62 ± 2.80%) of polysaccharides by UAE were higher than those by HWE (extraction rate of 24.95 ± 2.78% and purity of 75.33 ± 6.15%) (P < 0.05). Scanning Electron Microscopy (SEM) images of residues by UAE showed more broken cells than those by HWE. Fourier Transform Infrared (FTIR) spectra showed that the dialyzed ACP extracted by HWE and UAE (DACP-HWE and DACP-UAE) had similar characteristic absorption peaks of polysaccharides. Both DACP-HWE and DACP-UAE solutions showed typical shear thinning and temperature-independent behaviors (25–90 °C) and UAE resulted in polysaccharides with remarkably lower viscosity in comparison with HWE. DACP-UAE solutions exhibited more liquid-like state while DACP-HWE solutions solid-like system. Data indicated that ultrasound treatment may be a useful means for extraction of polysaccharides from Auricularia cornea var. Li.

Chemical and rheological properties of polysaccharides from litchi pulp

Litchi polysaccharide (LP) was extracted from litchi pulp. Its chemical composition, microstructure, zeta potential, flow and viscoelastic behavior were investigated. LP contained uronic acid (41.18%), neutral sugar (42.23%), and protein (2.72%). The monosaccharide composition was mostly arabinose, galactose, and a small amount of mannose, rhamnose and glucose. Scanning electron microscopy (SEM) showed LP was porous network structure. LP concentration had no effect on its zeta potential value while salts reduced them. LP showed shear-thinning behavior during the tested shear rate range. The power-law model was used to evaluate the flow behavior of LP; both its flow behavior index and consistency index changed with different concentrations. The viscosity of LP increased under acidic conditions (pH2–4), but was stable with heat treatment. The LP dispersion displayed as a liquid viscoelastic behavior in 1% and 2% concentrations and behaved as an elastic gel at 3% concentration as well as the addition of NaCl and CaCl2.

Effects of extraction methods on the rheological properties of polysaccharides from onion (Allium cepa L.)

In this work we described the rheological properties of polysaccharides (HBSS, CHSS, DASS, CASS) sequentially extracted from onion (Allium cepa L.). Four onion polysaccharides (ACLPs) solutions resulted into significant differences on their rheological properties. ACLPs solutions showed non-Newtonian shear-thinning behavior over the range of 0.5–2.5%. At concentration of 1%, the apparent viscosity of CHSS was observed to be the highest. The apparent viscosity of ACLPs solutions decreased with the acidic pH (4.0) or alkaline pH (10.0) which was further declined at higher temperature (90 °C). After the addition of various salts, ACLPs had apparent differences on apparent viscosity. The G′ (storage modulus) and G″ (loss modulus) of ACLP solutions were increased with increasing oscillation frequency. Moreover, the crossover value of oscillation frequency gradually decreased with increasing concentration of ACLPs. Our results exhibited that among the ACLPs, CHSS can be used as supplements in the food industry as thickening agent, gelling agent and stabilizer.

A systematical rheological study of polysaccharide from Sophora alopecuroides L. seeds

The rheological properties of polysaccharide (SAP) from Sophora alopecuroides L. seeds were systematically investigated by fitting different models. The steady flow testing indicated that SAP exhibited shear-thinning behaviors, which were enhanced with increasing concentration and decreasing temperature. This was demonstrated quantitatively by Williamson and Arrhenius models. According to the generalized Morris equation, SAP exhibited random coil conformation with the potential to form weak gel-like network. On the other hand, multiple results of dynamic tests confirmed the viscoelastic properties of SAP, showing oscillatory behaviors between a dilute solution and an elastic gel. Furthermore, SAP solutions were thermorheologically stable without remarkable energetic interactions or structural heterogeneity, since their rheological patterns were successfully applied to Time-temperature superposition (TTS) principle, modified Cole-Cole analysis and Cox-Merz rule.

Effects of Extraction Methods on In Vitro Biological Capacities and Rheological Properties of Polysaccharides from Red Pepper Stems.

The purposes of this study were to produce polysaccharides from red pepper stems using different extraction methods and evaluate their chemical composition, in vitro biological capacities, and rheological properties. Two polysaccharides were extracted from red pepper stems using an autoclave and alkali treatments, and the extracts were named PAU and PAL, respectively. The contents of total phenolics and flavonoids were significantly higher in PAU than those in PAL. PAU exhibited greater scavenging activities on 2,2-diphenyl-1-picrylhydrazyl radicals, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals, superoxide radicals, and nitrite compared to PAL, suggesting that PAU served as better antioxidants. Similarly, in vitro inhibitory abilities against carbohydrate hydrolyzing enzymes of PAU were higher than those of PAL. Steady shear rheological analysis demonstrated that PAU showed higher psuedoplastic shear-thinning behavior compared to PAL. Based on the results from dynamic shear rheological properties, it was found that both samples had predominantly viscous behavior rather than elastic behavior.

Rheological properties of polysaccharides from Dioscorea opposita Thunb.

This study investigated the chemical components and rheological properties of polysaccharides from Dioscorea opposita Thunb. Graded alcohol precipitation was used to extract Dioscorea opposita polysaccharide samples (S1, S2, S3 and S4). The monosaccharides, amino acid content and molecular weight of each sample were measured and compared. The rheological properties of the polysaccharide samples at different concentrations, temperatures and pH values were studied. The rheological properties of S1, S2 and S3 exhibited pseudoplastic properties and "gel-like" behaviour. The viscosity of S1 was improved with rising temperatures, especially temperatures higher than 80°C, which may be caused by the starch gelatinisation. The acidic and basic environments may break the structures of S3 and S4. However, the extreme conditions improved the viscosity of S1. This work was a basic investigation of the Dioscorea opposita polysaccharides, contributing to the function of yam products and applications of natural thickeners in the food industry.

Chemical and rheological properties of polysaccharides from fruit body of Auricularia auricular-judae

Polysaccharide was extracted from Auricularia auricular-judae with hot water (AP). AP consisted mostly of carbohydrates (72%) and proteins (8%). The monosaccharide compositions mostly are Glucose (62%), Mannose (33%) and a small amount of Galactose (5%). The extracellular polysaccharide dispersions showed shear-thinning (pseudoplastic) behavior and its pseudoplasticity was more pronounced for 2% polysaccharide dispersion. The Power-law model was used to evaluate the viscosity curves of AP and both its viscosity and consistency indices changed as the concentration increased. The viscosity of polysaccharides dispersion decreased with the addition of salt and also at extreme pH values. AP dispersion behaved as a weak gel in the concentration of 0.5% and 1% and as a true gel at higher concentration (e.g, 2%). The addition of 1 M CaCl2 to AP and changing dispersion pH to acid or alkali decrease its gel strength. AP exhibited excellent thermal stability as assessed by rheology and DSC, suggesting the material could be used in food system which requires heat tolerance.

Galactans: an overview of their most important sourcing and applications as natural polysaccharides

Since last decades, lot of biological and rheological properties of polysaccharides and oligosaccharides were described. Among them, galactans and more especially sulfated galactans from seaweeds have shown interesting and specific properties not only as texturing agents but also as biological active compounds on several organisms. This class of polysaccharides includes classical sulfated galactans extracted from seaweeds and classified as agar and carrageenans. However, some galactans are more complex and their specific structural features have been characterized after their extraction from terrestrial plants, seaweeds but also animals and microoragnisms. This review catalogues the origins, structural characteristics and potentialities of these polysaccharides and their oligosaccharides derivatives.

Rheological properties of polysaccharides produced by a Zoogloea sp.

A newly isolated marine bacterium, identified as Zoogloea sp., produced two different polysaccharides: one was water-soluble and the other was cell-bound. Both had non-Newtonian, pseudoplastic fluid behaviour and the solutions had low activation energies. The solutions of these polysaccharides showed rheological behaviour over a wide range of pH (2–12) and temperature (20–80 °C), and compatibility with NaCl.

Unusual rheology of a branched, water-soluble chitosan derivative

The rheological properties of polysaccharides are exploited for many industrial applications which have created an increasing demand for new inexpensive derivatives with improved performance1. N-Aklylation of the linear polysaccharide chitosan with various aldehydo-, keto- or lactone sugars affords branched-chain, water-soluble derivatives of high molecular weight for which the extent of branching as well as the branch conformation, length and type can readily be modified by appropriate choice of reagents and reaction conditions2. The products exhibit a correspondingly broad spectrum of rheological properties. We report here on some unusual non-newtonian features of one of these derivatives, 1-deoxylactit-1-yl chitosan, which displays low-shear newtonian behaviour, a medium-shear viscosity increase (dilatancy), and a high-shear viscosity drop (pseudoplasticity). In conditions of steady shear the shear stress-time function varies in the different shear rate regimes. A 2% solution of this derivative exhibits unique oscillatory behaviour under steady shear at the transition point between the dilatant and pseudoplastic regimes.