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In this study, a high molecular weight arabinoxylan (AX, Mw: 694 kDa) from wheat bran was alkaline extracted and covalently linked with Catechin (CA) by free radical catalytic reaction. Comparing to AX, arabinoxylan-catechin (AX-CA) conjugates demonstrated an extra UV–vis absorption peak at 274 nm, a new FT-IR absorption band at 1516 cm−1 and new proton signals at 6.5–7.5 ppm, which all confirmed the covalently linked structure. Grafting CA onto AX not only decreased the molecular weight, thermal stability and apparent viscosity of AX, but also enhanced its inhibition effects on starch digestibility in vitro. The in vitro fermentation test with pig feces showed that the degradation & utilization rate of AX, the total short-chain fatty acid (SCFA) and acetic acid levels produced all were significantly delayed after grafting. This study provided a novel approach to synthesize AX-CA conjugates that could be a novel dietary fiber of enhanced functional/bioactive properties using in the fields of functional foods and medicine. [ABSTRACT FROM AUTHOR]

Objectives: In order to elucidate the antibacterial activity and mechanism of S. alboflavus TD-1 active metabolites, the minimal inhibitory concentration of R. solanacearum and other effects on cell wall, cell membrane, nucleic acid, protein and cell morphology were studied. Besides, based on LCMS-IT-TOF, the active metabolites of S. alboflavus TD-1 were preliminarily analyzed. Results: In this study, We found that the active metabolites had obvious inhibitory effect on R. solanacearum, and the minimal inhibitory concentration (MIC) of R. solanacearum was 3.125 mg/mL. And the treatment of 10 mg/mL active metabolites can increase the permeability of R. solanacearum membranes, destroy the cell wall integrity, inhibit the synthesis of bacterial nucleic acids and proteins, and cause leakage of bacterial nucleic acids and proteins, obstruct the normal expression of proteins and destroy their bacterial morphology. At the same time, We speculated the molecular weights corresponding to the six compounds were 618, 615, 615, 615, 646, 646, respectively among the active metabolites, and it was found that were highly unstable. Conclusions: The active metabolites produced by S. alboflavus TD-1 liquid fermentation contain components that can significant inhibitory effects on R. solanacearum. It had the potential to develop biocontrol agents against bacterial wilt and be a kind potential sources for the preparation of functional anti-pathogenic microbial agents. [ABSTRACT FROM AUTHOR]

Corn bran hemicellulose was extracted from de-oiled and de-starched corn bran using 0.3 M alkali at 120 °C. Following neutralization, ethanol (75%) precipitation, dialysis, protein digestion, re-precipitation in ethanol, and freeze-drying, purified corn fiber gum (PCFG) was obtained in overall yield of 45.96%. PCFG gave a single peak by high performance size exclusion chromatograph, and had average molecular weight of 296 kDa. Monosaccharide composition, methylation, and GC–MS analysis indicated that PCFG was comprised of three monosaccharides, arabinose (ara f), xylose (xyl p) and galactose (gal p) with the following linkage: t-ara f , 17.09%; 1,3-ara f , 12.43%; t-xyl p , 16.13%; 1,4-xyl p , 11.57%; 1,3,4-xyl p , 26.02%; 1,2,3,4-xyl p , 10.46%; t-gal p , 6.37%. Partial acid hydrolysis suggested that arabinofuranose sugar residues were substituted onto a 1,4-linked xylan backbone. Extensive 1D and 2D NMR spectroscopy was used to identify and confirm the following linkages: t-xyl p , 1,2,3,4-β-D-xyl p, t-α-L-ara f , 1,2-α-L-ara f and 1,4-β-D-xyl p. Several other linkage fragments were also deduced: t-ara f →2-ara f →2- O -(1,3,4-xyl), t-ara f →2-ara f →3- O -(1,2,4-xyl), t-ara f →2-ara f →3-ara f, and t-gal→2-ara. Image 1 • Purified corn fibre gum (PCFG) was extracted from corn bran. • Major monosaccharides in PCFG were arabinose, xylose, and galactose. • Glyosidic linkages in PCFG were identified by NMR and methylation analysis. • Monosaccharide sequence was determined by partial hydrolysis and NMR. [ABSTRACT FROM AUTHOR]

The structure and conformation relationships of a heteropolysaccharide (Glc p A)Xylan in terms of various molecular weights, Xyl p /Glc p A ratio and the distribution of Glc p A along xylan chain were investigated using computer modeling. The adiabatic contour maps of xylobiose, Xyl p Xyl p (Glc p A) and (Glc p A)Xyl p Xyl p (Glc p A) indicated that the insertion of the side group (Glc p A) influenced the accessible conformational space of xylobiose molecule. RIS-Metropolis Monte Carlo method indicated that insertion of Glc p A side chain induced a lowering effect of the calculated chain extension at low Glc p A:Xyl p ratio (Glc p A:Xyl p = 1:3). The chain, however, became extended when the ratio of Glc p A:Xyl p above 2/3. It was also shown that the spatial extension of the polymer chains was dependent on the distribution of side chain: the random distribution demonstrated the most flexible structure compared to block and alternative distribution. The present studies provide a unique insight into the dependence of both side chain ratio and distribution on the stiffness and flexibility of various (Glc p A)Xylan molecules. [ABSTRACT FROM AUTHOR]

The conformational properties of gum ghatti and its fractions were investigated using high performance size exclusion chromatography (HPSEC) coupled with multiple detectors, static light scattering (SLS) and dynamic light scattering (DLS) methods. The measured Mark–Houwink equation parameters α (0.5 < α < 0.8) indicated a random coil conformation of four fractions: F50 was more rigid than the other fractions, whereas F65 exhibited a loosely extended chain that is close to a spherical conformation. DLS and SLS measurements in aggregate free (0.5 M NaOH) solution further confirmed the conformational properties. The high positive A 2 value of each fraction indicated that 0.5 M NaOH solution is a good solvent for gum ghatti. The values of R g and R h decreased with molecular weight in the order of F80, F65 and F50. The less branched fraction F50 ( ρ = 1.694) has a random coil conformation in 0.5 M NaOH solution, whereas F65 and F80 exhibited random coil close to spherical conformation due to their highly branched structure. [ABSTRACT FROM AUTHOR]

Abstract: The conformational properties of a high molecular weight polysaccharide (60P) extracted from Artemisia sphaerocephala Krasch (ASK) were investigated. The M w and R g of 60P were obtained using both static light scattering and HPSEC techniques, which were 590 kDa and 56 nm, respectively. Dynamic light scattering measurement indicated that 0.5 M NaOH solvents exhibited the ability to reduce/eliminate aggregates of 60P. 60P in 0.5 M NaOH showed strong concentration dependence, but minimal angular dependence. The average structure parameter ρ (R g/R h) value of 1.75 indicated that 60P exhibited a random coil conformation in 0.5 M NaOH solution. The conformational parameters (derived from R g vs M w and R h vs M w) from HPSEC also suggested a random coil conformation of 60P in 0.1 M NaNO3 solution (eluent for HPSEC). The characteristic ratio and the persistence length obtained from the random flight model and wormlike cylinder model both indicated a semi-flexible structure of 60P. [Copyright &y& Elsevier]

Abstract: Using 60% (w/v) ammonium sulfate precipitation, a heteropolysaccharide (designated 60S), with relatively low molecular weight (38.7kDa), was isolated from the seeds of Artemisia sphaerocephala Krasch. The structural properties of 60S were elucidated by partial acid hydrolysis, methylation analysis, 1D and 2D NMR spectroscopy, and MALDI-TOF-MS. The results of the partial acid hydrolysis and methylation analysis indicated that the main chain of 60S consisted of (1→4)-linked d-Manp and (1→4)-linked d-Glcp in a molar ratio of 1:1.3. Over half of the glucosyl residues in the main chain were branched at the O-6 position. The terminal sugar residues were mainly composed of T-Araf, T-Arap, T-Galp, T-GlcpA, and T-Glcp. Besides, 3-Araf and 2-Galp were also observed in comparable amounts. Based on all the aforementioned results and the data obtained by 1D and 2D NMR spectroscopy as well as MALDI-TOF-MS, a structure of 60S is proposed as follows: ▪ R could be one or some of -(3-α-Araf) n -(A), T-α-Galp (B), T-α-Glcp (C), T-Araf (H) or T-Arap. [Copyright &y& Elsevier]

Abstract: The extraction and fractionation methods as well as the physicochemical properties of Artemisia sphaerocephala Krasch polysaccharide (ASKP) were studied. ASKP was extracted from the outer layer of the seeds with high ratio of hot water to seeds (400:1, v/w). The yield of water-soluble ASKP was 13.6% (w/w). High performance size exclusion chromatography (HPSEC) results indicated that ASKP had two components with different molecular weights. The high molecular weight (Mw, 551.3KDa) fraction 60P was separated from the low molecular weight fraction 60S (Mw, 38.7KDa) by precipitation in 60% (w/v) ammonium sulfate salt solution. Steady flow rheological tests revealed that the apparent viscosity of 1.5% (w/v) ASKP decreased logarithmically with the increasing temperature. Small strain oscillation tests suggested that 4% (w/v) 60P solution was a typical viscous fluid. ASKP was composed of 66.9% (w/w) neutral sugar and 15.8% (w/w) uronic acid; 60P comprised of 55.4% (w/w) neutral sugar and 25.8% (w/w) uronic acid, while in 60S, the percentage of neutral sugar and uronic acid were 87.1% and 10.4%, respectively. Relative monosaccharide composition analysis showed that 60S was composed of 38.3% glucose, 28.1% mannose, 24.2% galactose and 9.4% arabinose, while the 60P fraction contained 80.5% xylose, 10.9% arabinose, 5.0% glucose, 2.3% galactose and 1.2% rhamnose. 60S exhibited the highest surface activity compared to ASKP, 60P, ASKPE (ASKP with protein removed) and 60PE (60P with protein removed) although no protein was detected in this fraction. [Copyright &y& Elsevier]

Abstract: The structure of a high molecular weight heteropolysaccharide (60P) isolated from Artemisia sphaerocephala Krasch was elucidated using methylation analysis and 2D NMR spectroscopy. 60P (Mw: 551kDa) was isolated from A. sphaerocephala Krasch (ASK) seeds, using hot water extraction and ammonium sulphate salt precipitation. Methylation and GC–MS analysis indicated that 60P was mainly composed of three types of sugar residues: 4-Xylp (27.8%), 2,4-Xylp (26.0%) and T-GlcpA (22.5%); small amount of 4-GalpA, 4-Glcp, T-Araf, T-Arap and 4, 6-GalpA were also detected with comparable molar ratio. Based on the results of monosaccharide composition, methylation analysis and NMR spectroscopy, a proposed structure is shown below: Display Omitted R represents one of the following groups: T-Araf, T-Arap, T-Araf →3-Araf (1→ and T-Arap →3-Araf (1→. [Copyright &y& Elsevier]

The effective utilization of by-products still poses a challenge in the food industry. In this work, soluble dietary fiber (SDF) extracted from okara was modified by steam explosion (SE) via adjusting steam pressure (1.0, 1.5, and 2.0 MPa) and SE duration (60 and 120 s). The structural and emulsification properties of modified SDF were studied. The untreated SDF exhibited a low yield (5.17%) and poor emulsification properties due to its large molecular weight (162.67 kDa), compact structure, and high interfacial tension (14.27 mN/m). SE increased SDF content by a maximum of 30.31%, 4.86 times higher than that of untreated SDF. Under mild SE conditions (1.0 MPa for 60 s), SDF displayed a loose structure with abundant side chains and a higher glyoxylate content (26.77%). Its near-neutral contact angle (82.0°) and lower interfacial tension (12.69 mN/m) endowed it with higher emulsification capacity, smaller emulsion droplet size, and enhanced emulsifying stability. The molecular weight of SDF decreased and the specific surface area enlarged with increasing SE intensity. Notably, SDF exhibited the best interfacial adsorption characteristics under SE of 2.0 MPa for 120 s, attributed to its low molecular weight (46.99 kDa) and higher protein content (7.58%). Overall, the improved emulsification properties of SDF were attributed to the synergistic effects of amphiphilic equilibrium, electrostatic repulsion, spatial resistance, and enhanced droplet-to-droplet interactions. [Display omitted] • Soluble dietary fiber (SDF) derived from okara is modified by steam explosion (SE). • SDF content reaches 30.31% at 1.0 MPa for 120 s of SE, 4.86 times higher than okara. • SE-modified SDF has loose structure, proper wettability, and low interface tension. • SDF exhibits the best interfacial adsorption property at 2.0 MPa for 120 s of SE. [ABSTRACT FROM AUTHOR]

Abstract: Physicochemical properties of different β-glucan purified from oat, barley and wheat, were investigated by measuring the composition, molecular weight, intrinsic viscosity ([η]), and rheological properties. The main objective was to investigate the relationship between effects of regulation of cholesterol metabolism and antioxidant property on db/db diabetic mice of β-glucans and their molecular weights and viscosities. Metformin was used as the positive control. The levels of blood glucose, serum lipid, liver lipid, superoxide dismutase (SOD) and malondialdehyde (MDA) in liver were determined. Results showed that average values of molecular weight (MW) of β-glucan from oat, wheat and barley were 172 kDa, 635 kDa and 743 kDa; the viscosities of β-glucans were positively correlated with their corresponded molecular weights, and wheat and barley β-glucan showed significant shear thinning ability compared to oat β-glucan; Barley β-glucans had higher G′ compared to wheat and oat, and the latter had higher G″. Blood glucose differences were not significant due to high variability, however serum TC, TG, liver TC, TG and LDL-C were lower in β-glucan fed groups compared to control. Moreover, the HDL-C was higher in β-glucan fed groups compared to control group. The addition of β-glucan fed to the db/db diabetic mice significantly (P < 0.05) increased their liver SOD activities and reduced their MDA levels (P > 0.05). A correlation between the measured biological parameters and the molecular weight or viscosity of β-glucan was observed. Lack of β-glucanase degeneration was the main cause of the low MW β-glucan and its diminished physiological effect. [Copyright &y& Elsevier]

Polysaccharides and polyphenols are bioactive components that co-exist in many plant foods. Their binary interaction in terms of the structure-function relationships, however, has not been well clarified. This study elucidated the correlation between the structural and physiological properties of galactomannan (GM) -catechin monomer complexes and GM with different branching or molecular weight (Mw). Results indicated that locus bean gum with lower branching degree (Gal/Man is 0.259) bound more readily to EGCG with adsorption rate of 19.42 %. EGCG and ECG containing galloyl groups were more inclined to form hydrogen bonds with GMs, significantly improving the adsorption by GMs. The introduction of EGCG could enhance the antioxidant activity and starch digestion inhibition of GM, which positively correlated with the adsorption capacity of EGCG. The guar gum (GG) with higher Mw (7384.3 kDa) could transport 71.51 % EGCG into the colon, while the retention rate of EGCG reaching the colon alone was only 46.33 %. Conversely, GM-EGCG complex with lower Mw (6.9 kDa) could be readily utilized by gut microbiota, and increased production of short-chain fatty acids (SCFAs). This study elucidated the structure-properties relationship of GM-EGCG complexes, and provide a new idea for the development and precision nutrition of polysaccharides-polyphenol complexes fortified functional foods. [Display omitted] [ABSTRACT FROM AUTHOR]

To understand the changes in arabinoxylan (AX) during breadmaking, multi-step enzyme digestion was conducted to re-extract arabinoxylan (AX-B) from AX-fortified bread. Their structural changes were compared using HPSEC, HPAEC, FT-IR, methylation analysis, and 1H NMR analysis; their properties changes in terms of enzymatic inhibition activities and in vitro fermentability against gut microbiota were also compared. Results showed that AX-B contained a higher portion of covalently linked protein while the molecular weight was reduced significantly after breadmaking process (from 677.1 kDa to 15.6 kDa); the structural complexity of AX-B in terms of the degree of branching was increased; the inhibition activity against α-amylase (76.81 % vs 73.89 % at 4 mg/mL) and α-glucosidase (64.43 % vs 58.08 % at 4 mg/mL) was improved; the AX-B group produced a higher short-chain fatty acids concentration than AX (54.68 ± 7.86 mmol/L vs 44.03 ± 4.10 mmol/L). This study provides novel knowledge regarding the structural and properties changes of arabinoxylan throughout breadmaking, which help to predict the health benefits of fibre-fortified bread and achieve precision nutrition. [Display omitted] • Arabinoxylan (AX) in bread was re-extracted using a multi-step enzyme hydrolysis method. • Breadmaking decreased the molecular weight and increased the structural complexity of fortified arabinoxylan. • The re-extracted AX could better inhibit the α-amylase and α-glucosidase activity than the original AX. • The re-extracted AX showed different in vitro fermentability compared to the original AX. • The related mechanisms towards the structure and property changes of AX were discussed. [ABSTRACT FROM AUTHOR]

This study explored the effects of wheat bran arabinoxylan (AX) of various molecular structures on the functional and in vitro digestibility of wheat starch. AX was separated with sequential ethanol precipitation into different fractions (L-Fra and H-Fra), followed by acidic treatment at varied time to convert L-Fra into different subfractions (H-Sub, M-Sub and L-Sub), and the structural features of AX and its subsequent fractions were compared. The Mw and branching degree of the fractions were decreased in the order of H-Fra (545 kDa, 1.15), L-Fra (86 kDa, 0.35), H-Sub (38 kDa, 0.16), M-Sub (21 kDa, 0.10) and L-Sub (7 kDa, 0.08). The functional properties, such as pasting properties, rheological properties, thermal properties, and their effect on the in vitro digestibility of wheat starch-AX combinations, were closely related to the molecular structures of AX. AX with higher Mw, higher branching degree and phenolic content could better inhibit the starch gelatinization and retrogradation, thus reducing the apparent viscosity and gelling properties of wheat starch. The possible mechanisms can be illustrated as 1) AX could compete for water with starch to inhibit granule expansion; 2) AX could not only adsorb on the surface of starch granules through hydrogen bonds but also entangle with the leached amylose and wrap on the surface of granules; 3) AX contained phenols, leading them to inhibit granule expansion through non-covalent interactions with starch molecules. Overall, this study provides a theoretical basis to improve the quality of wheat starch foods and extend the shelf life of wheat foods. [Display omitted] • Arabinoxylan (AX) fractions with various structural features were obtained. • The molecular weight (Mw), degree of branching (DOB) and phenols of AX were explored. • AX with higher Mw, higher DOB and phenols could better inhibit starch gelatinization. • AX with higher Mw, higher DOB and phenols could better inhibit starch retrogradation. • All AX with various structures could inhibit the in vitro digestibility of starch. [ABSTRACT FROM AUTHOR]

Highlights: [•] Structure of high Mw β-d-glucan. [•] Increased NO of macrophages. [•] Unique conformation transitions. [ABSTRACT FROM AUTHOR]

• Five polysaccharide sub-fractions were purified via ethanol fractional precipitation. • Structural features and immunomodulatory activity of five sub-fractions were compared. • WASP-40 with higher DE displayed strong immunomodulatory effects on RAW264.7 cells. • The structure-activity relationships were discussed. The physicochemical properties, structural features and structure-immunomodulatory activity relationship of pectic polysaccharides from the white asparagus (Asparagus officinalis L.) skin were systematically studied. Using sequential ethanol precipitation, five sub-fractions namely WASP-40, WASP-50, WASP-60, WASP-70 and WASP-80 with distinct degree of esterification (DE) and molecular weight (Mw) were obtained. The Mw and DE values were decreased with the increase of the ethanol concentrations. Structurally, although 4-α-D-Gal p A was the dominant sugar residue in all fractions, the molar ratios were decreased, whereas other sugar residues including arabinose- and mannose-based sugar residues overall increased with the increase of ethanol concentration. In addition, the effects of sub-fractions on the RAW 264.7 cells indicated that pectic polysaccharides with the higher DE value showed a stronger immunomodulatory activity. Moreover, the structure-activity relationship was also discussed in this study, which extends the value-added application of asparagus and its processing by-products. [ABSTRACT FROM AUTHOR]

Ultrasonication, xylanase and trifluoroacetic acid (TFA) treatments were applied to modify wheat bran arabinoxylan (AX) molecules. Molecular weight (Mw) distribution analysis, methylation analysis, rheological analysis and starch in vitro digestibility test were followed to compare the structural and functional properties of AX under different treatments. Different degradation methods decreased the Mw of AX in distinct manners, resulting in fractions with different structural features. Ultrasound treatment decreased the Mw of AX (640 kDa) to medium size range (640–100 kDa) with a slightly decreased degree of branching (DOB). Xylanase and TFA treatments could generate fragments with relative lower Mw (<100 kDa) compared to ultrasound treatment. However, sugar residues of AX from xylanase treatment showed a much higher DOB (47.89) and better solubility than those from TFA treatment. AX of larger Mw fractions showed higher apparent viscosity under the shear rate (50.3/s) close to the value induced by gastrointestinal peristaltic. In vitro digestion experiments of AX-starch mixture and AX fortified bread both showed that the higher Mw of the AX demonstrated a better inhibitory effect against starch digestibility, leading to a higher percentage of resistant starch. According to differential scanning calorimetry (DSC) analysis, AX could inhibit the retrogradation of wheat starch during bread storage, which provides complementary information for the above-mentioned conclusions. Image 1 • Three arabinoxylan fractions with different molecular weight were obtained. • The structural and functional features of different fractions were investigated. • All fractions showed inhibition on in vitro digestibility of starch and bread. • All fractions could inhibited the retrogradation of bread during storage. [ABSTRACT FROM AUTHOR]

• White asparagus skin polysaccharide (WASP) was isolated, which belonged to the pectic family. • Physicochemical and structural properties of WASP were systematically studied. • A proposed structure of WASP was established. • WASP showed immunomodulatory activities by RAW264.7 cell lines. The physicochemical properties, structural features and immunomodulatory effects of the white asparagus (Asparagus officinalis L.) skin polysaccharides (WASP) were systematically studied. WASP showed a pectic-like structure with a relatively low degree of esterification (DE, 18%); the weight-average molecular weight (Mw) and intrinsic viscosity were 76.1 kDa and 13 mL/g, respectively. Structurally, the dominated sugar residue of WASP was 4-α-D-Gal p A (39.7 mol%), while other residues including α-L-Ara f , 3-α-L-Rha p , 2,4-α-L-Rha p , and 4-β-D-Gal p were also detected with a comparable amount. A proposed structure of WASP was also presented. Physiologically, WASP could modulate the immune response of RAW 264.7 macrophages through increasing the release of immune factors (IL-6, TNF-α and IL-10) and improving the expression of mRNA. To conclude, the pectic-like polysaccharides from white asparagus (Asparagus officinalis L.) skin could be potentially used as an immunomodulatory agent in functional food. [ABSTRACT FROM AUTHOR]