Water-soluble Polysaccharide Fraction Research Articles

Structure and emulsifying properties of unprecedent glucomannan oligo- and polysaccharides from Amazonia Acrocomia aculeata palm fruit

Acrocomia aculeata fruit pulp contains oil (4.1–82.8 % fresh matter) and carbohydrates (6.6–98.0 % fresh matter). To date, only the oil fraction is valorized because very little is known about the nature of carbohydrates. This study explores new ways of adding value to this pulp by developing simple and efficient extraction processes for its carbohydrate components and characterizing their structure and physicochemical properties over two harvest periods. A water-soluble monosaccharide fraction F1 (solubility limit (SL): 98.5–99.3 g/L) (yield: 21 % dry pulp (DP)), a water-soluble polysaccharide fraction F2 (SL: 93.3–95.3 g/L) (yield: 26 % DP) and two additional water-insoluble polysaccharide fractions F3 and F4 (SL: <8 g/L) (yields: 10 and 19 % DP, respectively) were isolated. NMR structural characterizations of fraction F2 revealed it to be a linear glucomannan with β-(1 → 4) osidic linkages between d-Manp and d-Glcp residues. F2 is unique for its d-Manp/d-Glcp ratio of 3:1 and the position of its acetyl group (13–14 %, C-2 d-Manp). Finally, the polysaccharide showed a molecular weight (Mw) variation ranging from 8.2 × 104 to 1.1 × 103 Da over the two harvest periods, with remarkable emulsifying properties associated with a low Mw of F2 (stability >6 months, 1 % w/v in a water-in-oil emulsion).

Characterization, hypoglycemia and antioxidant activities of polysaccharides from Rhodosorus sp. SCSIO-45730

In this study, three new and highly purified water-soluble polysaccharides fractions (RSP-1, RSP-2 and RSP-3) were isolated from Rhodosorus sp. SCSIO-45730 with varying chemical compositions. All samples were polysaccharides with non-triple helical structure, in which RSP-1 mainly contained 1,4-linked Gal p , 1,3,6-linked Gal p and t-Glc p , while RSP-2 and RSP-3 were 1,4-linked Gal p , 1,4,6-linked Gal p and t-GalA p . The three polysaccharides all exhibited different morphology features, but they presented random coil configurations, which contained lots of pyranoid polysaccharides with α/β glycosidic bonds. RSP-1 possessed stable thermal property and good emulsifying property. The hypoglycemic assays demonstrated that RSP-2 exerted the strongest inhibitory activities on α-amylase (IC 50 =0.56 mg/mL) and α-glucosidase (IC 50 =0.05 mg/mL) with mixed-typed inhibition and competitive inhibition, respectively. Meanwhile, the antioxidant activities revealed that RSP-1 and RSP-3 exhibited marked effects. • Three new acidic polysaccharides were successively isolated and characterized. • RSP-1 possessed stable thermal property and good emulsifying property. • RSP-2 exhibited notable hypoglycemic activity. • RSP-2 inhibited α-amylase and α-glucosidase activities in a mixed and competitive type, respectively. • RSP-1 and RSP-3 showed strong antioxidant activity.

Antioxidant properties of water-soluble polysaccharides prepared by co-culture fermentation of straw and shrimp shell.

Herein, we present a method for producing water-soluble polysaccharides (WSPs) by co-culture fermentation of straw and shrimp shells. The chitin-degrading strain was isolated and genotypically identified as the non-pathogen Photobacterium sp. LYM-1 in this study. Photobacterium sp. LYM-1 and Aureobasidium pullulans 2012 could coexist without antagonism. WSPs concentrations were higher in co-culture fermentations of Photobacterium sp. LYM-1 and A. pullulans 2012 (PsL/AP-WSPs) compared to monocultures (PsL-WSPs and AP-WSPs). FTIR was used to examine the polysaccharide properties of three WSP fractions. The monosaccharide compositions of three WSPs fractions were primarily composed of mannose, ribose, glucosamine, glucose, galactose, and arabinose with varying molecular weights and molar ratios according to HPLC analysis. PsL/AP-WSPs showed better scavenging effects on DPPH, ABTS, and OH free radicals, demonstrating the application potential of PsL/AP-WSPs from straw and shrimp shells. The maximum yield obtained under optimum conditions (fermentation time of 6 days, temperature of 31°C, inoculum concentration of 10% (w/v), and inoculum composition of 2:1) was 5.88 ± 0.40 mg/mL, based on the PsL/AP-WSPs production optimization by orthogonal design. The results suggest that an environmentally friendly approach for WSPs production from agro-food wastes straw and shrimp shells was developed.

Structural compositions and biological activities of cell wall polysaccharides in the rhizome, stem, and leaf of Polygonatum odoratum (Mill.) Druce

Polygonatum odoratum is a perennial rhizomatous medicinal plant and different plant parts have been used in the treatment of various ailments. Herein, we have investigated the structural compositions of rhizome, leaf, and stem cell walls. We found 30–44% of polysaccharides in these wall preparations were cyclohexanediaminetetraacetic acid (CDTA) extractable, the proportion of heteromannans (HMs) in the rhizome is nearly three-fold compared to that of the leave and stem. The pectic polysaccharides of the rhizome are also structurally more diverse, with arabinans and type I and type II arabinogalactans being richest as shown by linkage study of the sodium carbonate (Na2CO3) extract. In addition, the 2-linked Araf was rhizome-specific, suggesting the cell walls in the rhizome had adapted to a more complex structure compared to that of the leaf and stem. Water-soluble polysaccharide fractions were also investigated, high proportion of Man as in 4-linked Manp indicated high proportion of HMs. The 21.4 kDa pectic polysaccharides and HMs derived from rhizome cell walls induced specific immune response in mice macrophage cells producing IL-1α and hematopoietic growth factors GM-CSF and G-CSF in vitro.

Physicochemical, rheological properties and in vitro hypoglycemic activities of polysaccharide fractions from peach gum

In this study, peach gum was sequentially extracted by water at 25 °C, 95 °C and 0.1 M NaOH, obtaining room temperature water-soluble (PG-WE), hot water-soluble (PG-HWE), and alkali-soluble (PG-AE) polysaccharide fractions. These three kinds of polysaccharide fractions exhibited a similar arabinogalactan structure according to FTIR spectrum and monosaccharide composition. However, their molecular weight and chain conformation were different based on high-performance size exclusion chromatography analysis, which resulted in different rheological behavior. PG-WE and PG-HWE presented non-Newtonian behavior, and the apparent viscosity of PG-WE was higher than that of PG-HWE at concentrations of 2.0 % and 3.0 % (w/w). Dynamic sweep tests showed that PG-HWE solutions behaved as viscous fluids, while PG-WE solutions tended to form gel-like structures at concentrations higher than 2 % (w/w). Furthermore, PG-WE showed significant in vitro inhibition against α-glucosidase activity in a dose-dependent manner and reduced the fluorescence of α-glucosidase through dynamic quenching mechanism.

Optimization of ultrasonic-assisted extraction of polysaccharides from Hemerocallis citrina and the antioxidant activity study.

The present study discussed the optimization of the ultrasonic-assisted extraction of polysaccharides from daylily polysaccharides (DPs). The extracted crude polysaccharides were further separated and purified, and the antioxidant activities including 1,1-diphenyl-2-111 picrylhydrazyl (DPPH) radical scavenging, 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging, hydroxyl radical scavenging, and ferric-reducing antioxidant power (FRAP) activities of the obtained fractions were also evaluated. The results showed that the optimal ultrasonic-assisted extraction parameters with DPs yield of 15.25 ± 1.13% were water to powder ratio of 25 ml/g, extraction power of 694 W, extraction temperature of 71°C, extraction time of 38 min, and three times extraction. By DEAE Sepharose Fast Flow column, four water-soluble polysaccharide fractions (DP-1, DP-2, DP-3, and DP-4) were successfully obtained. Monosaccharide component analysis showed that the four obtained fractions were all hetero-polysaccharides that mainly contained rhamnose, arabinose, fructose, galactose, glucose, galacturonic acid, and glucuronic acid in different molar ratios. All the four DP fractions did show obvious antioxidant activities in vitro, and the DP-3 component had relatively high ABTS free radical scavenging activity. Overall, our research showed that DPs could provide cheap raw materials for the development of natural antioxidants in medicines, functional foods, and even cosmetics. PRACTICAL APPLICATION: This article deals with the optimization of the ultrasonic-assisted extraction of polysaccharides from daylily and its antioxidant activities. The results showed that the optimal ultrasonic-assisted extraction yield of DPs was 15.25 ± 1.13%. By DEAE Sepharose Fast Flow column, four water-soluble polysaccharide fractions were successfully obtained, and all the four DP fractions did show obvious antioxidant activities in vitro. Daylily polysaccharides could provide cheap raw materials for the development of natural antioxidants in medicines, functional foods, and even cosmetics.

Beneficial Health Potential of Algerian Polysaccharides Extracted from Plantago ciliata Desf. (Septentrional Sahara) Leaves and Seeds

Today, an ethnobotanical approach makes sense for identifying new active bioactive chemicals from uses of indigenous plants. Two water-soluble enriched polysaccharide fractions (L-PSPN and S-PSPN) were extracted by hot water extraction from the leaves and seeds of Plantago ciliata Desf. (1798), a Mzab indigenous herb currently used in Algeria by traditional healers. Primary investigation was performed for describing the main structural features of these polysaccharides (pectin- and heteroxylan-like compositions) by using colorimetric assays, FTIR spectroscopy, HPAEC/PAD and GC/MS-EI analyses. Some biological activities were also monitored, such as anticomplement, anti-inflammatory (phagocytic ability, NOX2 and MPO inhibitions) and anti-diabetic (α-amylase and α-glucosidase inhibitions). L-PSPC seems able to moderately modulate innate immune system (IC50 around 100 µg/mL) and contribute to wound-healing processes (IC50 close to 217 vs. 443 µg/mL for sodium heparin). S-PSPC shows some potential as an anti-hyperglycemic (IC50 around 4.7 mg/mL) and anti-inflammatory (IC50 ranging from 111 to 203 µg/mL) agent, as well as other (fiber) psyllium-like polysaccharides extracted from Plantago species.

The Structural Characterization of a Novel Water-Soluble Polysaccharide from Edible Mushroom Leucopaxillus giganteus and Its Antitumor Activity on H22 Tumor-Bearing Mice.

In the present study, a novel cold water-soluble polysaccharide fraction (LGP) with the average molecular weight of 1.78×106 Da was extracted and purified from Leucopaxillus giganteus and its primary structure as well as in vivo antitumor activity was evaluated. The monosaccharide composition of LGP was determined by ion chromatography to be galactose, xylose, glucose and fucose in a molar ratio of 2.568 : 1.209 : 1 : 0.853. Its backbone was composed of α-D-Glu, α-D-Xyl, α-D-Gal and α-L-Fuc. The results of in vivo antitumor experiment demonstrated that LGP could effectively protect immune organs, has excellent antitumor activity, and inhibit the proliferation of H22 solid tumors in a dose-dependent manner. By analyzing Annexin V-FITC/PI staining, cell cycle and mitochondrial membrane potential detection assay, we concluded that LGP induced apoptosis of H22 cells via S phase arrest and mitochondria-mediated apoptotic pathway. Our results could provide valuable information for the potential application of LGP as an anti-hepatoma agent.

Structural characterization and antioxidant activities of one neutral polysaccharide and three acid polysaccharides from the roots of Arctium lappa L.: A comparison

In this work, we comparatively analyzed the structure and antioxidant activities of different polysaccharide fractions from Arctium lappa L. A total of four water-soluble polysaccharide fractions (ALP-1, ALP-2, ALP-3 and ALP-4) were obtained from the roots of Arctium lappa L. They differed in monosaccharide composition, molecular weight and linkage mode. ALP-1 and ALP-2 mainly consisted of fructose, with average molecular weights of 2.676 × 103 and 2.503 × 104 g/mol, respectively. ALP-3 and ALP-4 were mainly composed of fructose, arabinose and galactose, with average molecular weights of 9.709 × 104 and 6.790 × 104 g/mol, respectively. Furthermore, Fourier transform infrared spectrometry, methylation analysis and nuclear magnetic resonance spectroscopy suggested that the main polysaccharide ALP-1 had a linear chain of (1 → 2)-linked β-D-Fructofuranosyl backbone (n ≈ 15) linked to a terminal (1 → 2)-linked α-d-Glucopyranosyl at the non-reducing end. All five polysaccharides displayed high antioxidant ability, especially ALP-4 in H2O2-induced HepG2 cell model and ALP-1 in metronidazole [MET]-induced zebrafish model. These findings provided comparative information on the structure and biological activity of different burdock polysaccharides and highlighted their potential as antioxidants in functional foods.

Extraction of a water-soluble polysaccharide fraction from lentils and its potential application in acidified protein dispersions

The extraction conditions of a water-soluble lentil polysaccharide fraction (SLPS) from lentil fibers were examined. The effect of temperature, pH, and time of extraction was evaluated, to determine optimal conditions resulting in a high yield of high molecular mass polysaccharides. The optimal extraction temperature and time combination was 120 °C for 90 min. Under these conditions, the yield was as high as 23.3% at pH 4 and 19.6% at pH 8. Further, two different extractions were carried out, both for 90 min at 120 °C, one at pH 4 (SLPS4) and the second at pH 8 (SLPS8), and the fractions characterized for composition and molecular mass. The weight average molecular mass (Mw) of the main component in the fraction was 830 kg/mol for SLPS4 and 1130 kg/mol for SLPS8. Albeit SLPS4 and SLPS8 showed the same sugar linkages, their composition was different: SLPS4 contained, glucose 52.7%, arabinose 27.6%, and galacturonic acid 6.0%, whereas SLPS8 contained arabinose 49.8%, glucose 19.1%, and galacturonic acid 13.2%. The polysaccharides were observed by a scanning probe microscope and showed a characteristic multi-branched structure, with sugar chains extending from the center to the periphery of the molecule. Both SLPSs were used as stabilizers in an acidified milk system, containing 3% (w/w) non-fat milk solids. At a concentration of 0.4% (w/w) both SLPS4 and SLPS8 were able to maintain a mono-modal distribution of fine particles in the range of pH between 3.6–4.4 or 3.8–4.4, for SLPS4 and SLPS8, respectively. This work demonstrates the potential for the creation of a value added ingredient from lentil polysaccharide.

Exploration of bioactive prospects of a polysaccharide fraction from Termitomyces heimii against colorectal cancer and broad spectrum bacteria

Termitomyces heimii is a highly cherished wild edible mushroom in India for its pleasant delicacy, rich proximate compositions and profound ethno medicinal applications. A water soluble crude polysaccharide fraction (THP-I) was isolated from dried fruit bodies of T. heimii and purified by GPC. The 1H- NMR spectrum of THP-I exhibited anomeric protons within chemical shifts (δH) between 3.40 to 4.0, indicating that the compound possess –CH and –CH2 functional groups, which resonate with the oxygen atoms of the –OH group, confirmed it as a polysaccharide. THP-I exhibited the MIC values of 62.5 and 125 <mu>g/ml against Staphylococcus aureus and Shigella flexneri respectively. DPPH and FRAP assays showed effective radical scavenging potential by THP-I. In vitro cytotoxicity of THP-I was evaluated by MTT assay and showed notable cellular toxicity against HCT cells at a dose concentration 200 <mu>g/ml. It is first time reported herein that, THP-I has effectively diminished hyperplasia in 1, 2-dimethylhydrazine (DMH) induced colon cancer of Swiss albino rats along with sprouting of goblet cells. Through the present study it is evident that polysaccharide from T. heimii exhibited manifold bioactivities and therefore could be exploited further for its undiscovered potential applications.

Purification, characterization, antioxidant, and antitumor activity of polysaccharides isolated from silkworm cordyceps.

Two new water-soluble polysaccharide fractions (SCP II-1 and SCP II-2) were obtained from silkworm cordycepsusing DEAE Sepharose FF and Superose 6 columns chromatography. The characterization of their basic structure was studied by high performance liquid chromatography, high performance ion chromatography, infrared spectroscopy and atomic force microscope (AFM). The results showed that the molecular weight of SCP II-1 and SCP II-2 were 35.2kDa and 23.4kDa, and they were mainly composed of ribose, mannose, glucose, and galactose in molar ratio of 1.0:27.38:8.52:17.99 and 1.0:21.21:1.95:14.28, respectively. The AFM topography confirmed the highly branched chain conformation of SCP II-1, while SCP II-2 had more polymerized chain morphology. These two fractions possessed excellent antioxidant and antitumor activities, especially SCP II-1 showed better inhibition than SCP II-2. Those data suggested that purified polysaccharides from silkworm cordyceps have potential application in functional food and pharmaceutical industry. PRACTICAL APPLICATIONS: Silkworm cordyceps is cultivated on the 5th instar larvae inoculated with Cordyceps sp. and the functions of cordyceps have been reported recently. The separation and purification of silkworm cordyceps polysaccharide is helpful to better exert important biological functions. The study on the structure-function relations of polysaccharides will be useful to the application of polysaccharides in functional food and pharmaceutical industry.

Preparation of newly identified polysaccharide from Pleurotus eryngii and its anti-inflammation activities potential.

The anti-inflammatory effects of two newly identified Pleurotus eryngii polysaccharides (WPEP, NPEP) were determined in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages in this study. Characterization analysis revealed that molecular weights of WPEP and NPEP were 167and 274kDa, and were mainly composed of glucose with β-type glycosidic linkages. WPEP and NPEP could significantly inhibit LPS-induced inflammatory responses by regulating the production of NO, Protaglandin E2 (PGE2 ), Interleukin-1β (IL-1β), Tumor necrosis factor-α (TNF-α), and Interleukin-6 (IL-6). This was through the blocking of the activation of Mitogen-activated protein kinase (MAPK) pathway by inhibiting phosphorylation of p38, extracellular regulation of protein kinases 1/2, and stress-activated protein kinase/jun aminoterminal kinase. Moreover, WPEP and NPEP inhibited NF-κB signaling by reducing nuclear translocation and phosphorylation of p65. Overall, our results, for the first time identified two P. eryngii polysaccharides and demonstrated the related anti-inflammatory effects, which indicated the favorable potential of P. eryngii polysaccharide as specific functional foods. PRACTICAL APPLICATION: This study prepared and characterized newly identified Pleurotus eryngii water-soluble polysaccharide fractions and elucidated the nutritional benefits, mainly the immune response related to anti-inflammatory activities by utilizing lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Collectively, results of this study suggested that the P. eryngii polysaccharide fractions could be considered as potential candidates for exploration in the development of new immunomodulatory agent or functional supplementary foods.

Polysaccharides from acerola, cashew apple, pineapple, mango and passion fruit co-products: Structure, cytotoxicity and gastroprotective effects

This study aimed to characterize the chemical structure of water-soluble polysaccharide fractions extracted from co-products of acerola, cashew apple, pineapple, mango and passion fruit, evaluating their gastroprotective effect in vivo associated to their antioxidant activity. The results from the structural analysis revealed that all fractions extracted from the co-products were heteropolysaccharides composed by the monosaccharides glucose, arabinose, galactose and d-galacturonic acid, and presented a pectic nature, which was evidenced by the predominant presence of arabinogalactan in their constitutions. The polysaccharides obtained from acerola, cashew apple and pineapple exhibited similarity in their morphology compared to those from mango and passion fruit. The fractions did not show cytotoxic effects for epithelial culture IEC-6A, and stimulated cell growth as visualized by the increase in cellular viability. Notable antioxidant activities were found for cashew apple (147 μM Trolox.g−1), pineapple (80.0 μM Trolox.g−1) and acerola (79.0 μM Trolox.g−1). These same polysaccharides promoted higher preservation of glutathione levels in mice stomach tissue, resulting in its effective protection from the damage caused by ethanol. On the other hand, high malondialdehyde levels were observed in the stomach tissues of the animals treated with the polysaccharides from mango and passion fruit. The co-products from acerola and cashew were able to protect the gastric mucosa of mice from the lesions induced by ethanol. The results found in this research introduce polysaccharide fractions extracted from acerola, cashew apple and pineapple co-products as safe and natural antioxidants, with a high potential to be applied in different industry fields.

Anti-diabetic potential of mucilage from Hippeastrum vittatum bulbs in streptozotocin-induced diabetic rats

Plants belonging to the family Amaryllidaceae have been the focus of abundant studies thanks to their structurally diverse alkaloids with excellent biological and pharmacological profiles. Nevertheless, the anti-diabetic properties of these plant species have been considered to a lesser extent, in particular those of the subfamily Amaryllidoideae. Hence, in this work, the potential hypoglycaemic effects of the crude mucilage of Hippeastrum vittatum (L'Her.) (syn. Amaryllis vittata) bulbs were examined at 150 and 250 mg/kg using the streptozotocin-induced diabetic rat model. Overall, as compared to the untreated diabetic rats, oral administration of the mucilage at 150 mg/kg significantly ameliorated the induced hyperglycaemia by 45.37% and 61.95% after 2 and 4 h, respectively, whereas the maximum hypoglycemic actions were observed at 250 mg/kg, causing 57.37% and 65.74% reduction in the elevated blood glucose levels after 2 and 3 h, respectively. These effects were also markedly comparable to those of the standard hypoglycaemic drug gliclazide (50 mg/kg, p.o.). As the first report on the anti-hyperglycaemic activity of the genus Hippeastrum, the obtained results enlighten the potential of the water-soluble polysaccharide fraction from this plant and other Amaryllidaceae species for the development of natural hypoglycaemic agents that could be helpful as alternative or complementary therapies for type-2 diabetes.

Extraction, structural characterization, and immunoregulatory effect of a polysaccharide fraction from Radix Aconiti Lateralis Preparata (Fuzi)

A water-soluble polysaccharide fraction named FZPS-1 was obtained from Radix Aconiti Lateralis Preparata (Fuzi in Chinese). Physicochemical and instrumental analyses indicated that the purified FZPS-1 with an average molecular weight of 6.29 × 106 Da was composed of D-arabinose and d-glucose with a molar ratio of 7.5:92.5. It would contain the main chain fragments of →4)-α-D-Glc-(1 → 4)-α-D-Glc-(1→, with the side chain of terminal α-L-Ara-(1 → linked at C6 of D-Glc skeleton. FZPS-1 exhibited significant antioxidative activity and immunomodulatory activity, wherein it promotes macrophage phagocytosis and increases the secretion of macrophage-derived biological factors in RAW 264.7 cells, and a cyclophosphamide-induced immunosuppressed model in a dose-dependent manner. Oral administration of FZPS-1 ameliorated chronic diarrhea in rhubarb-induced spleen deficiency rats and was related to its immunomodulatory activity. Therefore, the obtained FZPS-1 could be potentially utilized as a natural immunomodulatory agent in functional food supplements or drugs.

Structural analysis and potential immunostimulatory activity of Nannochloropsis oculata polysaccharides

The relevance of microalgae biotechnology for producing high-value compounds with biomedical application, such as polysaccharides, has been increasing. Despite this, the knowledge about the composition and structure of microalgae polysaccharides is still scarce. In this work, water-soluble polysaccharides from Nannochloropsis oculata were extracted, fractionated, structurally analysed, and subsequently tested in terms of immunostimulatory activity. A combination of sugar and methylation analysis with interaction data of carbohydrate-binding proteins using carbohydrate microarrays disclosed the complex structural features of the different polysaccharides. These analyses showed that the water-soluble polysaccharides fractions from N. oculata were rich in (β1→3, β1→4)-glucans, (α1→3)-, (α1→4)-mannans, and anionic sulphated heterorhamnans. The immunostimulatory assay highlighted that these fractions could also stimulate murine B-lymphocytes. Thus, the N. oculata water-soluble polysaccharides show potential to be further explored for immune-mediated biomedical applications.

Structural characterization and immunomodulatory activity of two novel polysaccharides derived from the stem of Dendrobium officinale Kimura et Migo

Abstract Two novel polysaccharide fractions, DOPW-1 and DOPW-2, were successfully isolated from the crude polysaccharide of Dendrobium officinale Kimura et Migo and purified using diethylaminoethyl (DEAE)-cellulose 52 and Sephacryl S-300HR column chromatography. Their average molecular weight, monosaccharide composition, and linkage were investigated and a possible structure of the repeat units was inferred. DOPW-1 and DOPW-2 exhibited better immunomodulatory activity than that of the major, water-soluble polysaccharide fraction (DOPW), significantly (P

Structural characterization, physicochemical properties and α-glucosidase inhibitory activity of polysaccharide from the fruits of wax apple

In this study, a novel water-soluble polysaccharide fraction (WAFP) was isolated from wax apple fruits. The structural characterization, physicochemical properties and α-glucosidase inhibitory activity of WAFP were investigated. The results indicated that WAFP had average molecular weight of 49.9 kDa, it was mainly composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with a molar ratio of 1.88: 2.20: 6.37: 1.48: 5.47: 2.82. Besides, the backbone of WAFP might consist of →4)-α-D-Glcp-(1→, →3,4)-β-D-Xylp-(1→ and →3)-β-D-Galp-(1→, and the side chains might be composed of →3,5)-α-L-Araf-(1→, T-α-D-Glcp, →3)-β-D-Manp-(1→, →4)-α-D-GalpA-(1→ and →2)-α-L-Rhap-(1→. AFM images revealed that the height of WAFP molecules was about 12.8 nm. WAFP had no triple-helix structure, and it exhibited a shear-thinning behavior in the solution. SEM results showed that WAFP presented loose and incompact appearance and rough surface with many small irregular particles existed in the state of aggregation. Moreover, WAFP showed significant inhibitory effect on the activity of α-glucosidase.

Rheological properties and chain conformation of soy hull water-soluble polysaccharide fractions obtained by gradient alcohol precipitation

In this study, we aim to reveal the properties of different fractions of soy hull soluble polysaccharide (SHSP) derived by alcohol precipitation and the related mechanism. Three fractions were obtained, designated as SHSP20, SHSP40 and SHSP60; every fraction has its advantage(s). The molecular weight, monosaccharide composition, functional groups, morphology, and other rheological properties of all SHSP fractions were investigated. The results showed that SHSP20 and SHSP40 accounted for 74.3% of soy hull soluble polysaccharide. FTIR spectrum confirmed the presence of uronic acid and protein in SHSP fractions. Also, the molecular weight of the polysaccharide fractions varied from 124.21 to 381.83 kDa. GC analysis indicated that mannose, galacturonic acid, and galactose were the main monosaccharide components of all the SHSP fractions. However, the monosaccharide types and ratios of the three SHSP fractions are significantly different. Furthermore, shear thinning behaviour of SHSPs solution was observed. SHSP40 exhibited the highest viscosity among samples tested. Atomic force microscopy further confirmed the various morphologies of SHSP fractions. The results suggest that SHSPs obtained by gradient alcohol precipitation have different molar masses and chain conformations.