Neutral Sugars Research Articles

Physicochemical and rheological characterization of pectin-rich polysaccharides from Gardenia jasminoides J. Ellis flower.

Gardenia (Gardenia jasminoides J. Ellis) is regarded as an edible medicine plant in China. Here, gardenia flower polysaccharide fraction (GFPF) was extracted by water at 90°C and its chemical composition, rheological properties, and antioxidant activities of GFPF were investigated. The GFPF extraction yield was 18.04 ± 1.81% (W/W) and mainly comprised neutral sugars (46.83 ± 3.14%), uronic acid (35.21 ± 0.17%), protein (1.63 ± 0.34%), and total phenol (9.49 ± 0.08 mgGAE/g). Galacturonic acid (41.05 ± 0.59%) was the main monosaccharide, and galactose, glucose, arabinose, rhamnose, xylose, mannose, and glucuronic acid were also detected in GFPF. Its degree of esterification was 32.76 ± 1.52%. FT‐IR spectra analysis showed a similar absorption pattern between GFPF and pectin from apple. The results suggested that GFPF was low methoxy pectin. Thermogravimetric analysis and zeta potential analysis indicated that the pectin was stable under high temperature and alkaline condition. Steady rheology showed that the GFPF dispersion was a shear thinned pseudoplastic fluid with high apparent viscosities at concentration above 2%. The degree of pseudoplasticity of the solutions increased with the concentrations increased and the temperatures decreased. DPPH and ABTS free radical scavenging assay indicated that GFPF had relatively high antioxidant activity. The results showed that gardenia flower was rich in pectin polysaccharides with low methoxy pectin. It had high apparent viscosities at concentration above 2% and had good antioxidant activity. The data suggested that GFPF can be a new resource of low methoxy pectin with potential application as thicker or gelling agents in food industry.

Modulating the hydration properties of pea hull fibre by its composition as affected by mechanical processing and various extraction procedures

From a technological point of view, the application of dietary fibre in foods is mostly related to their water-binding properties. Hydration properties are affected by several factors, of which the particle size and composition are the most relevant. In the present study, pea hulls were used as an example of a fibre source with a complex cellulosic rich cell wall structure containing low-methoxylated pectin. The goal of this work is to study the impact that the extraction of soluble compounds by several treatments exerts on the morphology, chemical composition and hydration properties of samples with a specific and narrow particle size distribution (i.e. ‘fine’ and ‘coarse’). Evaluated treatments were: incubation in water, in ethanol, in hot acidic conditions and with a chelating agent. The processed fibres were characterized in terms of gross composition, sodium content, neutral sugar profile, microstructure and water- binding properties. Incubating pea hulls with ethanol or water resulted in an increased total dietary fibre content and similar hydration properties. Pectin acidic extraction loosened the rigid cell wall matrix, increased the amount of soluble of the remaining fibre and enhanced water-binding properties. Chelating assisted pectin extraction presented the highest water-binding properties due to the formation of pectic-related sodium carboxylate structures that favoured the water uptake. Fine fibres contained a higher amount of soluble dietary fibre than the respective coarse ones. The present study highlights that the hydration properties of PHF can be markedly improved using pectin targeted chemical extraction procedures.

Growth Region Impacts Cell Wall Properties and Hard-to-Cook Phenotype of Canned Navy Beans (Phaseolus vulgaris)

Cellular mechanisms underpinning the hard-to-cook phenomenon are poorly understood. Navy beans (Phaseolus vulgaris) from the same cultivar but grown in different regions of North America showed different canning characteristics. Up to 46.4% more force was required to disrupt hard beans (HB) grown in Ontario compared with soft beans (SB) grown in Manitoba. HB absorbed 12.5% and 14.7% less water during blanching and canning, respectively. Microscopic assessment revealed that canning led to swelling of middle lamella and cell walls, but preservation of cell adhesion in both types of beans. Immunofluorescence microscopy showed reduced labelling of methyl-esterified homogalacturonan (HG) and more non-methyl-esterified HG and arabinan epitopes in HB. Compositional analysis indicated that the polysaccharides from HB were less water soluble and enriched in neutral sugars, including 46.5% more arabinose and 51.8% more galactose than in SB. ELISA analysis of polymers in the canning medium supported the increased solubility of cell wall polymers in SB. In the same cultivar, growth region affects cell wall properties with consequences for processing, eating and nutritional quality.

Thermal degradation of citrus pectin in low-moisture environment – Investigation of backbone depolymerisation

Thermal degradation of modified pectin samples with varying molecular structure during storage was recently studied at 60 °C and 80% relative humidity (rh) for 28 days. Demethoxylation and depolymerisation were identified as main degradation reactions. The present paper aims on improving the understanding of the different depolymerisation reactions and their interplay with demethoxylation during storage. Therefore, thermal degradaton of acidic and alkaline demethoxylated pectins was studied at a further reduced rh of 40%. The alterations were examined in detail via molecular parameters and were reflected by differential scanning calorimetry and attenuated total reflectance Fourier-transformation infrared spectroscopy. The impact of thermal degradation on pectin particle structure was studied via particle surface area and microscopy.At low relative humidity (rh) demethoxylation and depolymerisation were reduced, and the formation of brown reaction products, resulting from further decomposition of intermediate uronides and neutral sugars, was restricted. By comparing thermal degradation at different humidity, eliminative decarboxylation was identified as the main depolymerisation reaction.Reduction of rh affected also the alteration of pectin material properties, particle surface reduction was less pronounced. Molecular alterations were stronger in case of acidic demethoxylated samples, and alterations of material properties were higher in case of alkaline demethoxylated samples.

Development of a continuous-flow system for microwave-assisted extraction of pectin-derived oligosaccharides from food waste

This paper addresses the current lack of a scalable process for the extraction of “hairy” pectins to upcycle biomasses, by describing the design methodology, building and testing of a continuous microwave-assisted process for potato waste pectin extraction. Hairy pectins have been shown to present prebiotic activity. Conventional pectin extraction methods are not suitable to produce them, as they lead to degradation of hairy regions, in part due to long heating times. Microwave heating is considered an alternative due to its selective and rapid heating. The 2 kW single mode system developed in this study achieved good temperature control of ±2.5 °C, and a stable target temperature in ≈1 min processing time at a feed flow rate of 250 mL min−1. Pectin yields of 40–45% (indicated by the galacturonic acid content) were achieved, with a feed residence time of only 0.81 s followed by 20 min cooling-down under stirring. These yields were 59.75% higher on average than control experiments in batch conditions or under continuous heating. This indicates that a short heating time is sufficient to allow pectin hydrolysis, after which the rate limiting diffusion step can proceed during cool-down, minimising pectin degradation caused by prolonged exposure to high temperatures. The presence of hairy pectin regions in the extract was confirmed by neutral sugar analysis. The high starch content in potato necessitated a de-starching procedure. A sieving procedure was implemented, which removed more starch than enzymatic de-starching, resulting in a higher purity pectin extract and the ability to collect starch as a separate value stream. This work proves the suitability of microwaves to be used as a fast heating method to extract pectin from biomass, avoiding degradation, using a scalable continuous mode of operation.

Pectins from food waste: Characterization and functional properties of a pectin extracted from broccoli stalk

Currently about 60–75% of world broccoli production is wasted during harvesting. The aim of the present study was to extract and characterise the pectin present in broccoli stalks and to evaluate its functional properties. The stalks were initially treated with boiling ethanol to remove compounds such as pigments and free sugars and then the pectin (FB) was extracted with 0.1 M nitric acid for 30min. The pectic fraction FB (18% yield) was found to contain 75% galacturonic acid with a degree of methyl-esterification of 56%, and an acetyl content of 1.1%. Rhamnose and galactose were the main neutral sugars present. NMR analyses showed that FB was composed of homogalacturonan and rhamnogalacturonan I substituted with β-1,4-D-galactan. The molar mass of FB was 72.2 × 103 g/mol and the viscosity of a 5% (w/w) solution in 0.1M NaCl at pH 4 showed shear thinning behaviour with a low shear Newtonian plateau of ~100 Pa s at 25 °C. At the same concentration FB showed a weak gel like behaviour. FB (0.5–4%, w/w) was also able to stabilize medium chain triglyceride oil in water emulsions. The results suggest that broccoli stalk could be used as an alternative source of commercial pectins.

Utilization of the co-product of jaboticaba (Myrciaria jaboticaba Berg.) for pectin extraction

Pectin is a polysaccharide that can be applied to various food industry products to modify the viscosity of food. The objective of this work was to optimize the extraction of pectin of jabuticaba peel by modificating the yield, galacturonic acid content (AUA), esterification content (DE), pectin content (P), and neutral sugars (N). The experiment was performed using the technique of factorial planning of complete experiments and surface response analysis. The extraction can be reported through factorial planning with coefficients of determination (R²) of 0.92, 0.91, 0.89, 0.88 and 0.90 for the yield extraction, AUA, DE, P, and N, respectively. The content of AUA ranged from 22.82 to 65.35%, the DE varied from 26.72 to 77.50%, the percentage of P found in the extraction 25.50 to 66.12%. The best performance was verified utilizing the following parameters: extraction time less than 75 min, temperature of 70°C, and citric acid concentration of 0.75 mol.L-1.

Root-knot nematodes modulate cell walls during root-knot formation in Arabidopsis roots.

Phytoparasitic nematodes parasitize many species of rooting plants to take up nutrients, thus causing severe growth defects in the host plants. During infection, root-knot nematodes induce the formation of a characteristic hyperplastic structure called a root-knot or gall on the roots of host plants. Although many previous studies addressed this abnormal morphogenesis, the underlying mechanisms remain uncharacterized. To analyze the plant-microorganism interaction at the molecular level, we established an in vitro infection assay system using the nematode Meloidogyne incognita and the model plant Arabidopsis thaliana. Time-course mRNA-seq analyses indicated the increased levels of procambium-associated genes in the galls, suggesting that vascular stem cells play important roles in the gall formation. Conversely, genes involved in the formation of secondary cell walls were decreased in galls. A neutral sugar analysis indicated that the level of xylan, which is one of the major secondary cell wall components, was dramatically reduced in the galls. These observations were consistent with the hypothesis of a decrease in the number of highly differentiated cells and an increase in the density of undifferentiated cells lead to gall formation. Our findings suggest that phytoparasitic nematodes modulate the developmental mechanisms of the host to modify various aspects of plant physiological processes and establish a feeding site.

Comparative study on antidiabetic function of six legume crude polysaccharides

The antidiabetic function of polysaccharides prepared from six legumes: soybean, white kidney bean, red kidney bean, small black soybean, field bean, lentil were studied. Six legume polysaccharides' antidiabetic function in high-fat diet and streptozotocin-induced type II diabetic mice were compared. Their effects on body weight, fasting blood glucose (FBG), glycosylated serum protein (GSP), serum insulin levels (HOMA-IR), blood lipids (including total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), and high-density lipoprotein cholesterol (HDL-c)) were tested. Results showed that red kidney bean polysaccharides (RK) could alleviate the symptoms of emaciation, decreased the levels of FBG, GSP, TC, LDL-c and obviously reduced the concentration of TG and HOMA-IR (p < 0.05). RK exhibited greater antidiabetic potential in type II diabetic mice, compared with other legume polysaccharides. The chemical composition of six legume polysaccharides were determined. Composition analysis indicated that the six legume polysaccharides were obviously different in moisture, ash, neutral sugar, uronic acid, total phenolic content, total flavonoid content, amino acid composition and monosaccharide composition. Results indicated that the antidiabetic activities of RK might due to its higher content and specific structure of polysaccharide.

Effect of chitosan coatings on the evolution of sodium carbonate-soluble pectin during sweet cherry softening under non-isothermal conditions

The inhibiting effect of chitosan coating (2%) on the softening and sodium carbonate-soluble pectin (SSP) evolution of sweet cherries during non-isothermal storage was investigated. Chitosan coating significantly extend the softening (6.4% greater than the control group), maintained the SSP content (6.6% greater than the control group), and reduced the degradation of SSP by inhibiting the expression of the paPME1–5 genes, which regulating pectin methylesterase activity of sweet cherries under temperature variation. In addition, the results of methylation and monosaccharide composition indicated that the chitosan coating reduced demethylation of SSP and the loss of RG-I main and side chain neutral sugars. Atomic force microscopy images revealed that the coated sweet cherries contained more linked, branched, and long SSP chains and maintained the width of the pectin backbone (>140 nm). These results indicated that a chitosan coating is feasible to preserve postharvest fruit under non-isothermal conditions.

Effect of ionic liquid pretreatment on the physicochemical properties of hemicellulose from bamboo

Ionic liquid (IL) pretreatment of lignocellulosic biomass has been the focus of attention due to its numerous advantages compared with conventional methods. The change in the physicochemical properties of the three main components of this biomass during IL pretreatment is the key factor for their further utilization and conversion. In this study, hemicellulose extracted from bamboo was dissolved in three ILs with different imidazolium cations and the same anion of acetate, including 1-ethyl-3-methylimidazolium acetate (EmimAc), 1-butyl-3-methylimidazolium acetate (BmimAc), and 1-allyl-3-methylimidazolium acetate (AmimAc). The solubility of hemicellulose in the ILs was measured as a function of temperature from 120 °C to 150 °C. Hemicelluloses regenerated from the saturated IL solutions were characterized by using Fourier transform infrared spectroscopy, gel permeation chromatography, gas chromatography–mass spectrometry, 13C–1H heteronuclear single-quantum correlation nuclear magnetic resonance, and thermogravimetry. The solubility of hemicellulose in the three ILs was greatly affected by temperature, and the solubility increased with increasing temperature. The highest solubilities per 100 g of IL were 15.56, 15.09, and 6.73 g in BmimAc, EmimAc, and AmimAc, respectively. Hemicelluloses regenerated from saturated IL solutions showed similar physicochemical features with that of the original hemicellulose before being pretreated with ILs. These features included molecular weight, relative neutral sugar composition, structural feature, and thermal stability. Hence, hemicellulose was litter degraded during IL solving. In addition, the recovered EmimAc was analyzed after dissolving hemicellulose to a saturated state at 150 °C by using 13C and 1H NMR. The recovered IL contained minimal amounts of ethanol and other impurities.

Neutral monosaccharides and their relationship to metal contamination in mangrove sediments

Mangrove sediments act as an important natural sink and a secondary source for trace metals. The main objective of this study was to investigate metal contamination and its relationship to mangrove-derived carbohydrates in mangrove sediments. Sixteen metals (Be, V, Cr, Co, Ni, Cu, Zn, Ga, As, Sr, Cd, Sn, Sb, Ba, Tl, and Pb）were analyzed in the surface sediments from four sites at different latitudes on the southeast coastline of China. The sedimentary organic matter was characterized by Rock-Eval pyrolysis, and the neutral sugars were examined by gas chromatograph mass spectrometry. Our results from the enrichment factors indicated that the mangrove sediments were no enriched by Ga, Sr, and Ba, minor enriched by Be, V, Cr, Co, Ni, Cu, Zn, As, Sn, Sb, Tl, and Pb, and moderate enriched by Cd. Litterfall was a major source of organic matter in the mangrove sediments, and the neutral sugars were mainly derived from this litterfall. Significant correlations were detected between the total organic carbon, pyrolytic parameters, neutral sugars, and enrichment factors of V, Cr, Co, Ni, Zn, and Cd, suggesting the input of neutral carbohydrates played an important role in enhancing the metal accumulation in the mangrove sediments. The mangrove litterfall itself was a major source of metals for the sediments, and the mangrove-derived organic matter enhanced the sediment’s metal accumulation.

Effects of bovine serum albumin on the ethanol precipitation of sugar beet pulp pectins

Bovine serum albumin (BSA) was used as an auxiliary to improve the ethanol precipitation yield of sugar beet pulp pectin (SBPP). The adjunction of BSA reduced the zeta potential of SBPP solution to a certain extent, which indicated that they were related to each other by electrostatic interaction. The hydration radius (Rh) of SBPP molecules decreased with the addition of BSA, reflecting the decrease of hydration degree of SBPP molecules. The effect of BSA on the ethanol precipitation yield of SBPP at different ethanol concentrations and different pH values was studied. The results showed that the presence of BSA could significantly reduce the dependence of SBPP on ethanol during the precipitation process. The effect of BSA on the precipitation behavior of SBPP was also regulated by system pH. The results of pectin structural analysis showed that there was no significant difference between SBPPs precipitated along with BSA and the original pectin samples in terms of galacturonic acid (GalA), neutral sugar (NS) and degree of methylation (DM). The high-performance size-exclusion chromatography (HPSEC) analysis showed that BSA could precipitate together with SBPP, but did not contribute to the precipitation of small-sized pectic fractions in SBPP solution. SBPP-BSA co-precipitation products were used to stabilize oil-in-water emulsions, and the storage stability of the resulting emulsions was significantly higher than that of the SBPP-stabilized emulsions. This method provided a new idea for reducing the consumption of ethanol in pectin precipitation. Meanwhile, the pectin-protein complex product obtained by co-precipitation had a good performance at stabilizing emulsions.

High Flocculation of Coal Washing Wastewater Using a Novel Bioflocculant from Isaria cicadae GZU6722.

Chanhua (Isaria cicadae) was known as a rare entomogenous fungus with various pharmacological activities since a long time ago in China, which has attracted considerable attention. However, less knowledge was maintained about its products as potential bioflocculants. In this work, a bioflocculant IC-1 produced by Isaria cicadae GZU6722, consisted mainly of protein (4%) and polysaccharides including neutral sugars (52.75%) and galacturonic acid (38.14%), was characterized. It presented high efficiency in flocculating coal washing wastewater, and the flocculating efficiency could reach 91.81% by addition of 24 mg l–1 IC-1 compared to the addition of 60 mg l–1 APAM (anionic polyacrylamide) under the same treatment conditions. The highest flocculating efficiency reached 95.8% in the presence of 2% CaCl2. Compared to APAM, the flocculating efficiency of coal washing wastewater by IC-1 varied little with the increasing dosage. Although the flocs in the APAM-assisted sediment were larger than that in the IC-1-assisted sediment after 1 min of sedimentation, few flocs were still found in the supernatant of both treated samples after 10 min of sedimentation. More interestingly, it was observed under the microscope that the flocs in the IC-1-assisted sediments were more compact than that in the APAM-assisted sediments, suggesting that polymer bridging might take place after IC-1 was added into the coal washing wastewater. The evaluation of costs indicated that the use of IC-1 to treat the coal-washing wastewater may be an economical and feasible way to avoid the extra cost for post-treatment of conventional flocculants.

The effect of pectic polysaccharides from grape skins on salivary protein – procyanidin interactions

In this study, water and chelator-soluble pectic polysaccharide fractions were obtained from white grape skins, aiming to study their impact on the interaction between low polymerized grape seed procyanidins and salivary proteins. Water and chelator-soluble polysaccharide fractions were composed by uronic acids and neutral sugars, mainly arabinose and galactose, with water polysaccharide fraction showing a higher amount of branched pectic polysaccharides. Both polysaccharide fractions were able to mitigate salivary protein-procyanidin interactions, by a competition mechanism, resulting in a decrease of the amount of precipitated protein. Water polysaccharide fraction was the most effective in inhibiting salivary protein precipitation, especially for acidic proline-rich proteins, due to the higher affinity to interact with procyanidins (KA = 22222 M−1 and KA = 365 M-1 for water and chelator polysaccharides, respectively). The interaction between polysaccharides and procyanidins showed to be mainly governed by hydrophobic effect.

2-Phenoxyethanol: A novel reagent for improved sensitivity of carbohydrate quantification

Anthrone is a routinely used reagent for estimating carbohydrates (Polysaccharides) in research, development and pharmaceutical applications. In presence of sulphuric acid, the polysaccharide gets hydrolyzed to monosaccharides in the form of hydroxymethyl furfural or furfural. The furfural then reacts with anthrone to form a green color complex with a maximum absorbance at 625 nm. Though anthrone reacts well with polysaccharides containing hexoses (such as glucose and galactose) and rhamnose, it is less reactive with uronic acids (such as glucuronic acid and galacturonic acid) and hexosamines (such as fucosamine, glucosamine, galactosamine, mannosamine, pneumosamine). Here, we report a novel reagent, 2-Phenoxyethanol, which reacts with furfural or hydroxymethyl furfural resulting in higher absorptivity. This method is rapid, sensitive, simple and direct, and can be used for quantitative determination of any type of carbohydrate that contains neutral sugars and uronic acids. For these saccharides, the sensitivity of the assay using 2-Phenoxyethanol (2-PE) is twice over anthrone method. Uronic acids show improved sensitivity using 2-PE over Phenol and it is more than twice with glucuronic acid. 2-PE reagent method has greater application for quantification of carbohydrates when present in low concentration in vaccines/biologicals.

Physicochemical characterization and bile acid-binding capacity of water-extract polysaccharides fractionated by stepwise ethanol precipitation from Caulerpa lentillifera

Herein, water-extracted Caulerpa lentillifera polysaccharides were structurally characterized and their bile acid-binding capacities were investigated. WCLP-25, WCLP-40, WCLP-55, WCLP-70, and WCLP-85 were obtained by graded ethanol precipitation with ethanol concentrations of 25%, 40%, 55%, 70%, and 85%. The total carbohydrate, protein, uronic acid and sulfate contents as well as the monosaccharide composition, molecular weight, and rheological properties were determined. Their infrared spectra, thermogravimetric curves, and scanning electron microscopy (SEM) images were acquired. The hypolipidaemic effects of the WCLPs were assessed with in vitro simulated bile acid-binding capacity experiments. The WCLPs are high-molecular-weight sulfated heteropolysaccharides, and the ethanol concentration significantly influenced the physicochemical properties of the extract. The bile acid-binding capacities of WCLP-55 and WCLP-70 were significantly higher than those of the other tested WCLP samples, which may be due to their higher neutral sugar, uronic acid and sulfate contents or due to their higher viscosities and a larger sheet structure based on SEM. This study will broaden the sources of raw materials for functional foods and provide a reference for the scientific use of C. lentillifera.

3D biofilms: in search of the polysaccharides holding together lichen symbioses.

ABSTRACTStable, long-term interactions between fungi and algae or cyanobacteria, collectively known as lichens, have repeatedly evolved complex architectures with little resemblance to their component parts. Lacking any central scaffold, the shapes they assume are casts of secreted polymers that cement cells into place, determine the angle of phototropic exposure and regulate water relations. A growing body of evidence suggests that many lichen extracellular polymer matrices harbor unicellular, non-photosynthesizing organisms (UNPOs) not traditionally recognized as lichen symbionts. Understanding organismal input and uptake in this layer is key to interpreting the role UNPOs play in lichen biology. Here, we review both polysaccharide composition determined from whole, pulverized lichens and UNPOs reported from lichens to date. Most reported polysaccharides are thought to be structural cell wall components. The composition of the extracellular matrix is not definitively known. Several lines of evidence suggest some acidic polysaccharides have evaded detection in routine analysis of neutral sugars and may be involved in the extracellular matrix. UNPOs reported from lichens include diverse bacteria and yeasts for which secreted polysaccharides play important biological roles. We conclude by proposing testable hypotheses on the role that symbiont give-and-take in this layer could play in determining or modifying lichen symbiotic outcomes.

NOM mitigates the phytotoxicity of AgNPs by regulating rice physiology, root cell wall components and root morphology

Natural organic matter (NOM) affects the environmental behaviors of AgNPs, which may change their phytotoxicity to plants. However, more evidence can be provided to illustrate how NOM influences AgNPs-induced phytotoxicity. In this study, using rice (Oryza sativa) as a model, the effects of NOM, Suwannee River humic acid (SRHA) and fulvic acid (FA), on the dissolution and phytotoxicity of AgNPs were investigated. Silver ions decreased in both AgNPs and AgNO3 solution in the presence of NOM, and the effect of SRHA was stronger than FA. Image-XRF (iXRF) results showed that Ag mainly remained in the root rather than the shoot of rice seedling exposed to AgNPs. NOM mitigated the negative effects of AgNPs and AgNO3 on rice with lower germination inhibition rate, less chlorophyll reduction, more relative biomass and less O2•− content. Moreover, NOM improved root cell viability according to FDA fluorescent dye as well as maintained the normal root morphology. Interestingly, the neutral sugars content from pectin, hemicellulose 1, hemicellulose 2 and cellulose of root cell wall in AgNPs and AgNO3 treatments differed from the control, while it was close to the regular content in AgNPs/AgNO3+SRHA/FA groups, which implied that NOM regulated the changes. Besides, SRHA led to less germination and less relative biomass than FA due to different chemical characters. Thus, NOM needs to be considered when studying the phytotoxicity of AgNPs.

The activation of NF-κB and MAPKs signaling pathways of RAW264.7 murine macrophages and natural killer cells by fucoidan from Nizamuddinia zanardinii

Polysaccharides from Nizamuddinia zanardinii were extracted using water at elevated temperature and fractionated by a DEAE Sepharose FF column yielding four fractions (F1-F4). Crude and fractions were composed of neutral sugars (50.8–57.4%), proteins (10.8–18.1%), sulfates (7.5–17.3%) and uronic acids (3.5–7.7%). Various levels of galactose (13.4–44.4%), fucose (34.1–40.1%), mannose (14.1–33.2%) and xylose (7.4–15.2%) formed the building blocks of the polysaccharide structures. The weight average molecular weights (Mw) of polysaccharides varied between 40.3 and 1254.4 × 103 g/mol. F3 polysaccharide was the most active fraction stimulating RAW264.7 murine macrophage cells to secrete NO, TNF-α, IL-1β and IL-6, and activating NK cells to release TNF-α, INF-γ, granzyme-B, perforin, NKG2D and FasL through NF-κB and MAPKs signaling pathways. Highly-branched F3 polysaccharide mainly consisted of (1 → 2)-Fucp, (1 → 2,3)-Manp, (1 → 3)-Galp, (1 → 2)-Manp, (1 → 3)-Manp, (1 → 2,3,4)-Manp and (1 → 2,3,6)-Manp residues with great amount of (→1)-Fucp and (→1)-Xylp. Sulfates substituted at C-2 of fucose and galactose residues. Overall, fucoidan from N. zanardinii showed immense potency in boosting immune system through macrophages and NK cells activations and therefore suitable for further exploration in immune-mediated biomedical applications.