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Graphical abstract Highlights • Developed an AFM technique to probe adhesion in cellulose-based networks. • Characterized the nanoscale adhesion forces between cellulose fibres. • Assessed the effect of xyloglucan and arabinoxylan on nano-scale adhesion forces. • Provided insights into the effect of xyloglucan on cellulose-cellulose adhesion. Abstract Inter-fibre adhesion is a key contributing factor to the mechanical response and functionality of cellulose-based biomaterials. 'Dip-and-Drag' lateral force atomic force microscopy technique is used here to evaluate the influence of arabinoxylan and xyloglucan on interactions between nanoscale cellulose fibres within a hydrated network of bacterial cellulose. A cohesive zone model of the detachment event between two nano-fibres is used to interpret the experimental data and evaluate inter-fibre adhesion energy. The presence of xyloglucan or arabinoxylan is found to increase the adhesive energy by a factor of 4.3 and 1.3, respectively, which is consistent with these two hemicellulose polysaccharides having different specificity of hydrogen bonding with cellulose. Importantly, xyloglucan's ability to strengthen adhesion between cellulose nano-fibres supports emergent models of the primary plant cell walls (Park & Cosgrove, 2012b), which suggest that xyloglucan chains confined within cellulose-cellulose junctions play a key role in cell wall's mechanical response. [ABSTRACT FROM AUTHOR]

Highlights • Comparative structural characterization of leaf cell walls of desiccation-tolerant and desiccation-sensitive Selaginella species. • Leaf cell walls Selaginella species are mainly composed of hemicellulosic polysaccharides namely arabinoxylan, mannan and xyloglucan. • Desiccation induces significant structural alterations of the xyloglucan and arabinoxylan in S. involvens compared to S. kraussiana and S. moellendorffii. • Structural remodeling of these hemicellulosic polysaccharides is an important process leading to desiccation tolerance in Selaginella plants. Abstract Drought-induced dehydration of vegetative tissues in lycopods affects growth and survival. Different species of Selaginella have evolved a series of specialized mechanisms to tolerate desiccation in vegetative tissues in response to water stress. In the present study, we report on the structural characterization of the leaf cell wall of the desiccation-tolerant species S. involvens and two desiccation-sensitive species, namely S. kraussiana and S. moellendorffii. Isolated cell walls from hydrated and desiccated leaves of each species were fractionated and the resulting oligosaccharide fragments were analyzed to determine their structural features. Our results demonstrate that desiccation induces substantial modifications in the cell wall composition and structure. Altogether, these data highlight the fact that structural remodeling of cell wall hemicellulosic polysaccharides including XXXG-rich xyloglucan, arabinoxylan and acetylated galactomannan is an important process in order to mitigate desiccation stress in Selaginella. [ABSTRACT FROM AUTHOR]

Highlights • Xyloglucan and two pectic polymers were submitted to in vitro fecal fermentation. • Depending on pectic polymers structure, more acetate or propionate was produced. • Xyloglucan fermentation resulted in elevated rates of propionate production. • Specific bacterial groups were stimulated with each kind of tested dietary fiber. • Major microbiota shifts occurred during xyloglucan fermentation. Abstract Xyloglucans and pectic polymers can be obtained from a variety of plants ubiquitous in the human diet, however, their fermentability in the colon and consequent nutritional benefits are poorly understood. Here, we evaluated metabolite profiles and bacterial shifts during in vitro fecal fermentations of two isolated pectic polymers and a xyloglucan. Depending on their chemical structure, pectic polymers were more acetogenic or propiogenic. Xyloglucan fermentation also resulted in elevated propionate if compared to FOS. Bacteroides plebeius, B. uniformis , Parabacteroides distasonis and bacterial groups such as Blautia , Lachnospira, Clostridiales and Lachnospiraceae , presented distinct abundances on each dietary fiber ferment. PCA and heat map analysis showed that major microbiota shifts occurred during xyloglucan fermentation, but not pectin fermentation. These data suggest that uncommon carbohydrate structures (i.e. isolated, soluble xyloglucan) in the diet hold the potential to generate larger shifts in microbiota communities than commonly consumed fibers (i.e. pectins). [ABSTRACT FROM AUTHOR]

Highlights • Depolymerisation on microbial surfaces initiates fermentation of XG/AX by porcine faeces. • Depolymerised XG/AX released back into medium suggesting cross-feeding. • Acetate and propionate produced at the same time as XG/AX degradation. • Butyrate and gas production occur later than XG/AX degradation. Abstract Arabinoxylan (AX) and xyloglucan (XG) are important components of primary cell walls of cereal grains and vegetables/fruits, respectively. Despite the established health benefits of these non-starch polysaccharides, the mechanisms of their utilisation by the gut microbiota are poorly understood. In this study, the mechanisms of solubilised wheat AX and tamarind XG degradation were investigated under in vitro fermentation conditions using a porcine faecal inoculum. Through structural analysis of the polymers, we demonstrate that depolymerisation by microbial surface accessible endo -degrading enzymes occurs prior to active fermentation of AX or XG. Breakdown products are released into the medium and potentially utilised cooperatively by other microbes. Acetate and propionate are the main fermentation products and are produced concurrently with polysaccharide depletion. Butyrate, however, is produced more slowly consistent with it being a secondary metabolite. [ABSTRACT FROM AUTHOR]

Highlights • Acryloylated xylan acted as co-macromer/crosslinker in hybrid pHEMA/SBA15 hydrogels. • Spruce xylan/pHEMA hydrogels support the growth of fibroblast. • SBA15 particles (20% wt.) enhanced two-fold the mechanical properties of hydrogels. • Fibroblasts spread better on the hybrid hydrogel. Abstract A hybrid hydrogel (GHC-SBA15) based on spruce xylan (HC), 2-hydroxyethyl methacrylate (HEMA), and mesoporous silica (SBA15) was prepared with the intended use of fibroblast attachment and growth. Xylan was functionalized with acryloyl chloride to introduce vinyl groups and was crosslinked by radical polymerization with HEMA in presence of SBA15. Infrared spectroscopy and nuclear magnetic resonance confirmed the copolymerization of HEMA with xylan. Up to 20 wt.% addition, SBA15 was homogenously incorporated in the structured hydrogel network as observed by SEM. Moreover, nitrogen adsorption–desorption, small angle X-ray scattering and transmission electron microscopy indicated that the mesoporous SBA15 framework was maintained and that the hybrid hydrogel was a physical mixture of SBA15 with the copolymer HC/HEMA. Rheological analysis revealed that addition of 20% w/w SBA15 into hydrogel enhanced significantly the mechanical properties. In addition, we demonstrate that fibroblast L929 cells grew and spread on GHC-SBA15. Cell viability was within the expected range. [ABSTRACT FROM AUTHOR]

Thin xyloglucan-based hydrogel films have been synthetized and characterized in the prospect of producing wound dressings. Polyvinyl alcohol (PVA) and glycerol (Gro) were added to have an optimal combination of softness, conformability and resilience. Physical hydrogels have been transformed into permanent covalent hydrogels by reaction with glutaraldehyde (GA). Network structure-process-property relationships are discussed on the account of the results of several complementary characterizations: FTIR, rheology, thermal analysis, morphological analysis, moisture retention and swelling measurements. Selected formulations were also subjected to preliminary in vitro cytotoxicity tests. The physical and mechanical properties of some of the xyloglucan-based hydrogel films produced, combined with absence of cytotoxicity, make them suitable candidates for integration with sensors to monitor the wound healing process and further biological investigations in animal models. [ABSTRACT FROM AUTHOR]

Gelation kinetics of aqueous solutions of xyloglucan (XG) extracted from H. courbaril seeds were investigated, in-situ, during enzymatic removal of galactose units by oscillatory shear rheological measurements, at different XG and enzyme (β-galactosidase) concentrations. Increasing the enzyme concentration (C enz ) led to an increase of the gelation rate. Master curves of the evolution of the storage shear modulus at different C enz could be formed by time-C enz superposition showing that C enz influenced the kinetics, but not the gelation process and the final gel stiffness. The behaviour of gels formed by XG with different molar mass (M w ), prepared by endoglucanase hydrolysis, was evaluated as a function of the temperature. It was found that cooling led to a decrease of the crosslink density causing a decrease of the gel stiffness. The decrease of the crosslink density was sufficient to depercolate the network formed by relatively small XG with M w = 10 5 g mol −1 , but gels formed by XG with M w ≥ 8 × 10 5 g mol −1 persisted down to 10 °C. It is shown that the melting temperature and the gel stiffness at high temperatures can be controlled independently by varying the molar mass and the concentration of XG chains. [ABSTRACT FROM AUTHOR]

The impact of the matrix polysaccharides on the cellulose microfibrils structure as well as on the mechanical properties of cell walls still remains an open question. Therefore, the aim of investigations was to determine the simultaneous influence of (i) different concentrations of pectins with constant concentration of xyloglucan, and (ii) different concentrations of xyloglucan with constant concentration of pectins on cellulose structure. Composites of bacterial cellulose (BC) produced by Komagataeibacter xylinus are considered to mimic natural plant cell walls. This investigation showed that the lower the ratio of xyloglucan to pectin was, the higher Young’s modulus of BC composite was and also obtained cellulose microfibrils were thinner. The increasing concentration of xyloglucan to pectin also caused the drop down in microfibrils crystallinity degree with predominant structure of cellulose I β . In that case, also the length of cellulose chains was growing and reaching the highest value among all BC composites. [ABSTRACT FROM AUTHOR]

In this work, the properties of cellulose (CE)/xyloglucan (XG) biopolymer blends are investigated, taking inspiration from the outstanding mechanical properties of plant cell walls. CE and XG were first co-solubilized in an ionic liquid, 1-ethyl-3-methylimidazolium acetate, in order to blend these biopolymers with a varying CE:XG ratio. The biopolymers were then regenerated together using water to produce solid blends in the form of films. Water-soluble XG persisted in the films following regeneration in water, indicating an attractive interaction between the CE and XG. The final CE:XG ratio of the blends was close to the initial value in solutions, further suggesting that intimate mixing takes place between CE and XG. The resulting CE/XG films were found to be free of ionic liquid, transparent and with no evidence of phase separation at the micron scale. The mechanical properties of the blend with a CE:XG ratio close to one revealed a synergistic effect for which a maximum in the elongation and stress at break was observed in combination with a high elastic modulus. Atomic force microscopy indicates a co-continuous nanostructure for this composition. It is proposed that the non-monotonous variation of the mechanical performance of the films with XG content is due to this observed nanostructuration. [ABSTRACT FROM AUTHOR]

Hydroxypropyl methylcellulose (HPMC) and xyloglucan (XG) crosslinked with citric acid over a range of HPMC/XG weight ratios formed sustainable blend films characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, tensile tests, circular dichroism and determination of inhibitory activity against Staphylococcus aureus and Escherichia coli . Both in solution and in the crosslinked films, HPMC chains lost the original ordered conformation upon interacting with XG, giving rise to an entropic gain. The highest values of tensile strength (25 MPa) and Young’s modulus (689 MPa) occurred for the 50:50 HPMC/XG blend films. In vitro loading of gentamicin sulfate (GS) in the films amounted to 0.18 ± 0.05 −0.37 ± 0.05 g of GS per g polymer. At pH 7.4 and 37 °C, the GS release kinetics from the films fitted with the Korsmeyer–Peppas model revealed a non-Fickian release mechanism with diffusional coefficient n ∼ 0.7. The cross-linked films of HPMC, XG and their blends loaded with GS showed outstanding antibacterial activity against Staphylococcus aureus and Escherichia coli , disclosing their potential for novel biomedical applications. [ABSTRACT FROM AUTHOR]

Xyloglucan from tamarind seed has been submitted to an ultrasound treatment that reduces its molecular size to investigate the impact of molar mass on the interaction with cellulose. A low molar mass xyloglucan fraction (XGu, 1.04 × 10 5 g mol −1 ) was purified and its adsorption on the cellulose nanocrystal (CNC) surface has been investigated comparatively to the native fraction that presents high molar mass (XGn, 10.28 × 10 5 g mol −1 ). XGn arranged as loops and tails on CNCs whereas XGu formed trains onto the cellulose surface. Despite the extended conformation, XGu is able to cross-link cellulose nanocrystals in the layer-by-layer CNC-XG-CNC assemblies. Hydrolysis of model films by a xyloglucan-specific endoglucanase confirmed the greater accessibility of XGn loops and tails compared to the XGu trains. More importantly, in situ ellipsometry revealed that the presence of loops and tails facilitated swelling of CNC layers linked by XGn whereas the CNC-XGu-CNC structure did not experience swelling. [ABSTRACT FROM AUTHOR]

Partially degalactosylated xyloglucan from tamarind seeds (Deg-XG) is a very appealing biopolymer for the production of in situ gelling systems at physiological temperature. In this work, we observe that the morphology of hydrogels evolves towards high degrees of structural organization with time, yielding to dense stacks of thin membranes within 24 h of incubation at 37 °C. We also explore the possibility offered by gamma irradiation of controlling the time scale of this phenomenon, the final morphology and mechanical properties of the system. Structural and molecular modifications of Deg-XG with dose are investigated by FTIR, dynamic light scattering (DLS) and rotational viscosimetry. The impact on gelation ability and gel strength is studied by rheological analysis. The morphology evolution is investigated by SEM analysis, and absence of cytotoxicity verified by MTS assay and optical microscopy of neuroblastoma cells. [ABSTRACT FROM AUTHOR]

The structure of ethanol precipitated fraction from 1 M KOH extracted flaxseed kernel polysaccharides (KPI-EPF) was studied for better understanding the molecular structures of flaxseed kernel cell wall polysaccharides. Based on methylation/GC–MS, NMR spectroscopy, and MALDI-TOF-MS analysis, the dominate sugar residues of KPI-EPF fraction comprised of (1,4,6)-linked-β- d -glucopyranose (24.1 mol%), terminal α- d -xylopyranose (16.2 mol%), (1,2)-α- d -linked-xylopyranose (10.7 mol%), (1,4)-β- d -linked-glucopyranose (10.7 mol%), and terminal β- d -galactopyranose (8.5 mol%). KPI-EPF was proposed as xyloglucans: The substitution rate of the backbone is 69.3%; R 1 could be T-α- d -Xylp-(1→, or none; R 2 could be T-α- d -Xylp-(1→, T-β- d -Galp-(1 → 2)-α- d -Xylp-(1→, or T-α- l -Araf-(1 → 2)-α- d -Xylp-(1→; R 3 could be T-α- d -Xylp-(1→, T-β- d -Galp-(1 → 2)-α- d -Xylp-(1→, T-α- l -Fucp-(1 → 2)-β- d -Galp-(1 → 2)-α- d -Xylp-(1→, or none. The Mw of KPI-EPF was calculated to be 1506 kDa by static light scattering (SLS). The structure-sensitive parameter (ρ) of KPI-EPF was calculated as 1.44, which confirmed the highly branched structure of extracted xyloglucans. This new findings on flaxseed kernel xyloglucans will be helpful for understanding its fermentation properties and potential applications. [ABSTRACT FROM AUTHOR]

Reconstituted cellulose films were generated using residual bacterial cellulose membranes mechanically defibrillated (RBC fibrils) recycled following wound dressing production via a dry-cast process. Arabinogalactan (AG) extracted from Pereskia aculeata leaves and/or a xyloglucan (GHXG) from Guibourtia hymenifolia seeds were incorporating into the RBC at various compositions, and new films were created using the same process. Biocomposite properties were evaluated by scanning electron microscopy, contact angle (CA), and X-ray diffraction measurements. The attachment and proliferation of murine L929 fibroblasts on RBC and RBC/Hydrocolloids (HD) were also evaluated. RBC films with 20–30% GHXG replacement improved film stability and the inclusion of HD increased microfiber aggregation and reduced porous regions. Changes in the hydrophilic characteristics were also observed and owing to the adhesion effect the inclusion of HD on RBC led to a statistically significant effect of the mechanical properties of films. The RBC/AG films supported L929 adhesion similar to that observed for commercial bacterial cellulose, indicating their potential use for biomedical applications. [ABSTRACT FROM AUTHOR]

The molten salt hydrate, lithium chloride (LiCl)/urea/water has previously been shown to swell cellulose, but there has so far been no work done to explore its effect on other polysaccharides. In this paper we have investigated the solvent effects of LiCl/urea/water on four natural polysaccharides. Fenugreek gum and xyloglucan, which are both highly branched, were found to increase in viscosity in LiCl/urea/water relative to water, possibly due to the breakage of all intra-molecular associations whereas the viscosity of konjac glucomannan which is predominantly unbranched did not change. Locust bean gum (LBG) had a lower viscosity in LiCl/urea/water compared to water due to the disruption of aggregates. Confocal microscopy showed that fenugreek gum and LBG are able to bind to cellulose in water, however, the conformational change of fenugreek gum in these solvent conditions inhibited it from binding to cellulose in LiCl/urea/water whereas conformational change allowed xyloglucan to bind to cellulose in LiCl/urea/water whilst it was unable to bind in water. Konjac glucomannan did not bind to cellulose in either solvent system. These results provide new insights into the impact of polysaccharide fine structure on conformational change in different solvent environments. [ABSTRACT FROM AUTHOR]

Viscose fiber mills generate a lot of wastewater enriched with hemicelluloses. The structure of the hemicellulose in the wastewater was characterized and the hemicellulose was isolated to produce xylo-oligosaccharides (XOS). It was confirmed that the hemicellulose was mainly 4- O -methylglucuronoxylan with a small amount of glucomannan and xyloglucan. The 4- O -methylglucuronoxylan was completely de-acetylated and linear with a few 4- O -methyl glucuronic acid attached. After purified by the acid precipitation and washing, the hemicellulose was pretreated by dilute acid, and then subjected to xylanase hydrolysis. After the dilute H 2 SO 4 pretreatment at pH 2.6 and 150 °C for 30 min and the followed xylanase hydrolysis (65 IU/g xylan), the total XOS yield was improved from 0.215 to 0.578 g/g xylan. The percentage of XOS in the final sugar product was 68.9%. These results demonstrated the potential economical and environmental benefits of the process to utilize the byproducts from viscose fiber mills. [ABSTRACT FROM AUTHOR]

An ultrasound-assisted procedure was applied to the extraction of hemicelluloses from grape pomace at a mild temperature (20 °C). A Central composite design (CCD) was employed to optimize the ultrasound-assisted extraction (UAE) of hemicelluloses from grape pomace with the aim to maximize their extraction yield, and, also, the obtention of the main polymers forming this fraction: Xyloglucans (XLG), Mannans (MAN) and Xylans (XN). Extraction time ( X 1 ), solid:liquid ratio ( X 2 ) and KOH concentration ( X 3 ) were the variables used to optimize the process. The conditions that maximize (1) the extraction yield of hemicelluloses and the contents of (2) XLG, (3) MAN and (4) XN, were: (1) X 1 = 2.6 h ; X 2 = 1 :48 (w/v); X 3 = 0.4 M , (2) X 1 = 2.9 h ; X 2 = 1 :57 (w/v); X 3 = 2.25 M , (3) X 1 = 2.7 h ; X 2 = 1 :58(w/v); X 3 = 2.2 M , and (4) X 1 = 3 h ; X 2 = 1 :60 (w/v); X 3 = 2.3 M , respectively. Under these conditions, the maximum extraction yield of hemicelluloses, XLG, MAN and XN contents were: ∼7.9 ± 0.2%, ∼3.6 ± 0.02%, ∼1.1 ± 0.04% and ∼1.2 ± 0.02%, respectively. Close agreement between experimental and predicted values was found. The results suggest that the ultrasound-assisted extraction could be a good option for the extraction of hemicellulosic polysaccharides from grape pomace at industrial level. [ABSTRACT FROM AUTHOR]

Tamarind seed xyloglucan is a polymer reported to possess mucoadhesive property. In the present work, role of cysteine derivative of tamarind seed polysaccharide (thiomer) to enhance the mucoadhesion and its influence on drug permeation has been studied. The xyloglucan was first chemically modified to carboxymethyl derivative which was further converted to thiomer by conjugation with cysteine in presence of a coupling agent, EDAC. The matrix tablets of simvastatin prepared using thiomer demonstrated drug release retardation, increased mucoadhesion force and increased ex vivo permeation, the same were proportional to the increase in the amount of thiomer. The in vivo residence of thiomer placebo was more than 7 h in rabbit. Pharmacokinetic evaluation in rabbits indicated higher AUC for the formulation with highest content of thiomer and level ‘A’ correlation could be established from the generated dissolution and bioavailability data. [ABSTRACT FROM AUTHOR]

A novel polymer in the form of a thiolated derivative of natural tamarind seed polysaccharide or xyloglucan was synthesized and its chacteristics as a mucoadhesive polymer were studied as a part of the study undertaken herein. The synthetic route followed involves a two-step reaction mechanism of firstly oxidizing xyloglucan and then further conjugating it with l -cysteine to form thiolated xyloglucan or thiomer via imine linkage. The thiomer thus formed was characterized using various analytical techniques as differential scanning calorimetry (DSC), X-ray diffraction analysis (XRD), and nuclear magnetic resonance (NMR). Ellman's method was used to determine the numbers of thiol groups/g of thiolated xyloglucan. Zeta potential measurements were carried out for thiolated xyloglucan. Viscosities of the formulated xyloglucan and thiolated xyloglucan gels were comparatively evaluated along with the evaluation of mucoadhesive properties of the gels using ex vivo bioadhesion study employing freshly excised sheep intestinal mucosa. [ABSTRACT FROM AUTHOR]

Viscoelastic properties of aqueous solutions of xyloglucan extracted from Hymenaea courbaril seeds (Jatobá gum) were investigated by rheology over a wide range of concentrations and temperatures. The polymer was characterized in dilute solutions by light scattering measurements and size exclusion chromatography. Xyloglucan formed, in semi-dilute solutions ( C 0.3 wt%), a transient network with cross-links characterized by a broad distribution of lifetimes, independent of the temperature and concentration. Progressively, at higher temperatures (>60 °C), a second much weaker quasi-permanent network was formed and attributed to the exchange of intra- to inter-chain bonds. The stiffness of the second network increased with decreasing temperature, but it could be easily broken by applying a relatively weak shear stress and is readily reversible on re-heating, and partially reversible on resting at 20 °C. [ABSTRACT FROM AUTHOR]

To overcome the recalcitrant nature of biomass several pretreatment methodologies have been explored to make it amenable to enzymatic hydrolysis. These methodologies alter cell wall structure primarily by removing/altering hemicelluloses and lignin. In this work, alkali, dilute acid, steam explosion pretreatment are systematically studied for mustard stalk. To assess the structural variability after pretreatment, chemical analysis, surface area, crystallinity index, accessibility of cellulose, FT-IR and thermal analysis are conducted. Although the extent of enzymatic hydrolysis varies upon the methodologies used, nevertheless, cellulose conversion increases from <10% to 81% after pretreatment. Glucose yield at 2 and 72 h are well correlated with surface area and maximum adsorption capacity. However, no such relationship is observed for xylose yield. Mass balance of the process is also studied. Dilute acid pretreatment is the best methodology in terms of maximum sugar yield at lower enzyme loading. [ABSTRACT FROM AUTHOR]

This study aims at application of xyloglucan, polysaccharide polymer as novel film forming agent for ocular delivery of ciprofloxacin. Ciprofloxacin ocular films were prepared by the solvent casting method using xuloglucan (2%). The prepared formulations were evaluated for thickness, percentage drug content, surface pH, swelling, mechanical strength and in vitro drug release. The films were found to be of uniform thickness (0.20 ± 0.07 μm). The % drug content in the films was found to be 95.45 ± 0.25%. The cumulative % drug releases from the formulation was 98.85 at the end of 24 h. The formulations followed the anomalous transport release mechanism. Ocular irritancy study reveals safety of formulation to ocular mucosa. Thus, this study suggests that xyloglucan can act as a potential film forming polymer for ocular delivery of a ciprofloxacin. [ABSTRACT FROM AUTHOR]

Mixtures of gellan gum (GL) and a xyloglucan (XGJ) extracted from Hymenaea courbaril seeds were prepared in a solution of 0.15 mol L −1 NaCl. Rheology measurements revealed that 2.4 g L −1 pure GL formed a brittle hydrogel, and GL-XGJ blends showed improved pseudoplastic character with higher XGJ contents. SAXS analyses showed that the R g dimensions ranged from 1.3 to 4.9 nm, with larger values occurring as the amount of XGJ increased, and diffusion tests indicated that better diffusion of methylene blue dye was obtained in the network with a higher XGJ content. AFM topographic images of the films deposited onto mica revealed fewer heterogeneous surfaces with increased XGJ contents. The water contact angle revealed more hydrophobic character on all of the films, and the wettability decreased with increasing amounts of XGJ. Therefore, the demonstrated benefit of using XGJ blends is the production of a soft material with improved interface properties. [ABSTRACT FROM AUTHOR]

During processing of plant-based foods, cell wall polysaccharides and polyphenols, such as procyanidins, interact extensively, thereby affecting their physicochemical properties along with their potential health effects. Although hemicelluloses are second only to pectins in affinity for procyanidins in cell walls, a detailed study of their interactions lacks. We investigated the interactions between representative xylose-containing water-soluble hemicelluloses and procyanidins. Turbidity, ITC and DLS were used to determine the relative affinities, and theoretical calculations further ascertained the interactions mechanisms. Xyloglucan and xylan exhibited respectively the strongest and weakest interactions with procyanidins. The different arabinoxylans interacted with procyanidins in a similar strength, intermediate between xyloglucans and xylans. Therefore, the strength of the interaction depended on the structure itself rather than on some incidental properties, e.g., viscosity and molar mass. The arabinose side-chain of arabinoxylan did not inhibit interactions. The computational investigation corroborated the experimental results in that the region of interaction between xyloglucan and procyanidins was significantly wider than that of other hemicelluloses. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] Xyloglucan is natural polysaccharide suitable for mucosal delivery. [•] Xyloglucan based microspheres were prepared by spray drying technique. [•] Xyloglucan spray dried microspheres possess desired properties for pulmonary administration as dry powder inhalation. [•] In vitro dry powder inhalation performances demonstrate its suitability for pulmonary administration. [•] In vitro studies reveal improved pharmacokinetic parameters of a drug. [ABSTRACT FROM AUTHOR]

Abstract: Galactose units of spruce galactoglucomannan (GGM), guar galactomannan (GM), and tamarind (galacto)xyloglucan (XG) were selectively allylated. Firstly aldehyde functionalities were formed at the C-6 position via enzymatic oxidation by galactose oxidase. The formed aldehydes were further derivatized by an indium mediated Barbier–Grignard type reaction, resulting in the formation of homoallylic alcohols. In addition to allylic halides, the same reaction procedure was also applicable for GGM, when using propargyl bromide as halide. All reaction steps were done in water, thus the polysaccharides were modified in a one-pot reaction. The formation of the allylated, or propargylated, product was identified by MALDI-TOF–MS. All polysaccharide products were isolated and further characterized by GC–MS or NMR spectroscopy. By this chemo-enzymatic process, we have demonstrated a novel method for derivatization of GGM and other galactose-containing polysaccharides. The derivatized polysaccharides are potential platforms for further functionalizations. [Copyright &y& Elsevier]

Highlights: [•] Grapevine leaves were analyzed using high-throughput wall profiling tools. [•] Enzymatic oligosaccharide fingerprinting was used to analyze xyloglucan. [•] Paenibacillus sp. xyloglucanase treatment released XXFG and XLFG subunits. [•] Trichoderma reesei EGII also liberated XXXG units in addition to XXFG and XLFG. [•] These methods are suitable for profiling grapevine in systems-biology studies. [ABSTRACT FROM AUTHOR]

Highlights: [•] Polysaccharides identified in Brassica napus were partly similar to Brassica campestris. [•] Different from B. campestris, linear arabinan and XXGG-type xyloglucan were found. [•] Next to cellulose, the final residue still contained xyloglucan and pectins. [ABSTRACT FROM AUTHOR]

Highlights: [•] Xyloglucan-based block co-oligomer (XGO-b-XGO,Ac) was obtained by “click” reaction. [•] XGO-b-XGO,Ac self-assembled in water into spherical nanoparticles of 22nm. [•] As for Pluronic–F68, XGO-b-XGO,Ac stabilized gliadin and zein nanoparticles. [•] Narrower size distribution of zein nanoparticles was obtained with XGO-b-XGO,Ac. [ABSTRACT FROM AUTHOR]

Highlights: [•] We have used negative mode APCI doped with chloroform and tandem mass spectrometry to sequence xyloglucans. [•] Chloride anion attachment at atmospheric pressure gently ionizes mixtures of xyloglucans with no fragmentation. [•] Tandem mass spectrometry can be used to sequence the negatively charged xyloglucans. [ABSTRACT FROM AUTHOR]

Plant cell walls provide essential functions in cell recognition, differentiation, adhesion and wound responses. Therefore, it is tempting to hypothesize that cell walls play a key role in grafting, but to date there are no quantitative studies targeting on cell wall changes during grafting. The aim of this work was to investigate the dynamics of pectic and hemicellulosic polysaccharides at the graft junctions in tomato homografts throughout the first 12 days after grafting. Cell wall fractionation, combined with ATR-FTIR spectroscopy and gas-chromatography, evidenced a marked increase in pectin content and a decrease in the degree of methyl-esterification of homogalacturonan in scion and rootstock throughout grafting. Also, recovery of tightly-bound hemicelluloses decreased at late times after grafting suggesting an increase of cross-linked hemicelluloses along grafting. In addition, immuno-dot assays revealed an increase in xyloglucan and arabinogalactan proteins in the first days after grafting, pointing to a presumed role in tissue adhesion-cohesion. [ABSTRACT FROM AUTHOR]

Abstract: In this work, polysaccharide nanoparticles based on tamarind seeds xyloglucan are prepared, analyzed in term of characteristic sizes and morphology, and degraded by the action of a glycoside-hydrolase. Obtained in an aqueous NaNO2 solution (0.1M), these unaggregated nanoparticles have a characteristic diameter of ca. 60nm (DLS, AFM and TEM measures). They are not compact, but highly swollen and look like hyperbranched and dendrimer-like (soft sphere model) structures. This observation is coherent with the native structure of the xyloglucan macromolecules which are themselves branched. The enzymatic hydrolysis by cellulase of Trichoderma reesei of the xyloglucan nanoparticles is investigated. In particular, the apparent mass molecular weight drastically decreases meaning that the xyloglucan nanoparticles are effectively fully hydrolyzed by the endo-β-(1,4)-glucanase. Furthermore, we observe that the enzyme has to uncoil the nanoparticles before cutting the β-(1→4) bonds and digesting the xyloglucan. [Copyright &y& Elsevier]

Abstract: The present study was aimed to prepare tamarind seed nanoaggregates and its evaluation for ophthalmic delivery. The preparation of tropicamide-loaded tamarind seed xyloglucan nanoaggregates was optimized using face centred central composite experimental design, employing the concentrations of tamarind seed xyloglucan and Poloxamer-407, as independent variables. The results revealed that concentration of TSX has a significant antagonistic effect on particle size, while poloxamer displayed a significant synergistic effect on encapsulation efficiency. The optimal concentrations of TSX and poloxamer were found to be 0.45% (w/v) and 0.5% (w/v) respectively. The optimized formulation of tropicamide-loaded TSX nanoaggregates showed a significantly higher corneal permeation of tropicamide across the isolated goat cornea compared to commercial conventional aqueous formulation. The results revealed excellent mucoadhesive properties of TSX nanoaggregates. Further, the tropicamide-loaded TSX nanoaggregates formulation showed excellent ocular tolerance and biocompatibility as determined by hen''s egg test chorioallantoic membrane and resazurin assay on Vero cell lines. [Copyright &y& Elsevier]

Abstract: To prepare and explore the structure of native hemicellulose from tomato, extraction of the natively acetylated polysaccharides was achieved from partially depectinated cell walls by DMSO doped with LiCl. DEAE anion exchange chromatography of the LiCl–DMSO extract allowed the removal of residual acidic pectin and the isolation of acetylated glucuronoxylan. The hemicellulose neutral fraction from the anion exchanger was fractionated by size exclusion chromatography into xyloglucan (XyG) and galactoglucomannan (GgM) either as single major constituents or as mixtures of both. Residual hemicellulose in the cell wall was extracted by 4.0M and not 1.0M KOH. The fine structure of all LiCl–DMSO fractions and alkali extracts was assessed by coupling β-glucanase, β-mannanase and β-xylanase enzymatic degradations to the analysis of the resulting fragments by HPAEC and MALDI-TOF mass spectrometry. This approach revealed substitutions in part of the GgM fractions by pentose residues, presumably arabinose and/or xylose occurring in highly substituted block domains. It also demonstrated a different glucanase hydrolysis profile from 4.0M KOH compared to LiCl–DMSO soluble fractions. The present extraction and purification scheme allow the recovery of several populations of acetylated hemicellulose families which emphasize the structural diversity and complexity of these polysaccharides. [Copyright &y& Elsevier]

Abstract: Pressed potato fibre (PPF) has a high water holding capacity (WHC) affecting its processing as an animal feed. The aim of this study was to characterize cell wall polysaccharides (CWPs) in PPF and investigate their WHC. This was done via sequential extractions. Half of all CWPs were recovered in the hot buffer soluble solids extract as pectins (uronic acid and rhamnose) and galactans wherein most pectins (76%) from PPF were water soluble. Most likely, the network of CWPs is loosened during processing of potatoes. PPF showed a WHC of 7.4 expressed as the amount of water held per g of dry matter (mL/g). Reconstituting hot buffer soluble solids with buffer insoluble solids in water gave a WHC comparable to that of PPF. Removal of alkali soluble solids, which mainly comprised xyloglucans, lowered the WHC of the final residue. The results indicated that interactions between CWPs could affect the WHC of PPF. [Copyright &y& Elsevier]

Abstract: Biobased polymers such as starch and hemicelluloses from wood are of interest for packaging applications, but suffer from limitations in performance under moist conditions. Xyloglucan from industrial tamarind seed waste offers potential, but its Tg is too high for thermal processing applications. Regioselective modification is therefore performed using an approach involving periodate oxidation followed by reduction. The resulting polymer structures are characterized using MALDI-TOF-MS, size-exclusion chromatography, FTIR and carbohydrate analysis. Films are cast from water and characterized by thermogravimetry, dynamic mechanical thermal analysis, dynamic water vapor sorption, oxygen transmission and tensile tests. Property changes are interpreted from structural changes. These new polymers show much superior performance to current petroleum-based polymers in industrial use. Furthermore, this regioselective modification can be carefully controlled, and results in a new type of cellulose derivatives with preserved cellulose backbone without the need for harmful solvents. [Copyright &y& Elsevier]

Abstract: The effects of polysaccharides, including xyloglucan from Hymenaea courbaril (XG), galactomannans from Schizolobium parahybae (GMSP) and Mimosa scabrella (GMMS), xanthan gum (XT), sodium hyaluronate (HNa) and Fucogel® (FG), on the rheological behavior of cosmetic emulsions were evaluated. These incorporations gave rise to six emulsified systems, denoted XGE, GMSPE, GMMSE, XTE, HNaE and FGE, respectively. The emulsion consistency was found to follow the trend GMSPE>XGE>HNaE>FGE>XTE>GMMSE. In general, the addition of polysaccharides increased the viscoelastic properties of the emulsions and decreased the creep compliance. The neutral polysaccharides (GMSPE, GMMSE) led to better stability of the emulsions after storing for 20 days relative to charged polymers. It was found that polysaccharides XG, GMSP and GMMS, which come from the seeds of native Brazilian plant species, might be used to modify the flow properties and stabilities of oil–water emulsions. [Copyright &y& Elsevier]

Abstract: Self-assembled nano-arrays have a potential application as solid-phase diagnostics in many biomedical devices. The easiness of its production is directly connected to manufacture cost reduction. In this work, we present self-assembled structures starting from spin coated thin films of carboxylated polystyrene (PSC) and xyloglucan (XG) mixtures on both mica and silicon substrates. AFM images showed PSC nanospheres on top of a homogeneous layer of XG, for both substrates. The average nanosphere diameter fluctuated for a constant speed and it was likely to be independent of the component proportions on the mixture within a range of 30–50% (v/v) PSC. It was also observed that the largest diameters were found at the center of the sample and the smallest at the border. The detected nanospheres were also more numerous at the border. This behavior presents a similarity to spin coated colloidal dispersions. We observed that the average nanosphere diameter on mica substrates was bigger than the nanosphere diameters obtained on top of silicon substrates, under the same conditions. This result seems to be possibly connected to different mixture–surface interactions. [Copyright &y& Elsevier]

Abstract: We describe the mechanical defibrillation of bacterial cellulose (BC) followed by the dry-cast generation of reconstituted BC films (RBC). Xyloglucan (XGT), extracted from tamarind seeds, was incorporated into the defibrillated cellulose at various compositions, and new films were created using the same process. Microscopy and contact angle analyses of films revealed an increase in the microfibre adhesion, a reduced polydispersity in the diameters of the microfibrils and increased hydrophobic behaviour as a function of %XGT. X-ray diffraction analysis revealed changes to the crystallographic planes of the RBC and the biocomposite films with preferential orientation along the (110) plane. Compared with BC, RBC/XGT biocomposite with 10% XGT exhibited improvement in its thermal properties and in Young''s modulus. These results indicated a reorganisation of the microfibres with mechanical treatment, which when combined with hydrocolloids, can create cellulose-based materials that could be applied as scaffolding for tissue engineering and drug release. [Copyright &y& Elsevier]

Abstract: Salicornia brachiata is an extreme halophyte, growing opulently in salt marshes and considered as potential alternative crop for seawater agriculture. Salicornia seeds are rich in protein and tender-shoots are eaten as salad greens. Total cell wall carbohydrate was isolated from seedlings, digested with β-glucanase enzyme cocktail and oligosaccharide mass profiling (OLIMP) was performed by using MALDI TOF-TOF mass spectroscopy. Salicornia OLIMP is represented by characteristic mass peaks m/z 477.3297–2094.4363. MS spectra exhibit xyloglucan oligosaccharide building blocks, dominated by XXXG (1084.9927 m/z). Characteristic mass peaks (m/z) of xyloglucan oligomers (XXG, XXFG, XLXG and XLFG) were also detected, which showed resemblance to the mass profile of highly nutritious plant soybean. The present study is the first report on OLIMP for any edible halophyte, so far. OLIMP supports use of Salicornia as a potential source of dietary supplementation. Further linkage-analysis is required to get the structural information of oligosaccharides. [Copyright &y& Elsevier]

Abstract: The objective of present study was to enhance bioadhesive potential of xyloglucan by thiolation. Thiolation of xyloglucan was achieved with esterification with thioglycolic acid. Thiolated xyloglucan was characterized by NMR, DSC, and XRD analysis. Thiolated xyloglucan was determined to possess 4mmol of thiol groups/g of polymer by Ellman''s method. Comparative evaluation of mucoadhesive property of ondansetron containing in situ gel system of xyloglucan and thiolated xyloglucan using sheep nasal mucosa revealed higher ex vivo bioadhesion time of thiolated xyloglucan as compared to xyloglucan. Improved mucoadhesive property of thiolated xyloglucan over the xyloglucan can be attributed to the formation of disulfide bond between mucus and thiolated xyloglucan. Ex vivo permeation study conducted using sheep nasal showed improved drug permeation in formulation based on thiolated xyloglucan. In conclusion, thiolation of xyloglucan improves its bioadhesion and drug permeation without affecting the resultant gel properties. [Copyright &y& Elsevier]

Abstract: Mucoadhesive buccal films were developed using tamarind seed xyloglucan (TSX) as novel mucoadhesive polysaccharide polymer for systemic delivery of rizatriptan benzoate through buccal route. Formulations were prepared based on 32 factorial design with concentrations of TSX and carbopol 934P (CP) as independent variables. Three dependent variables considered were tensile strength, bioadhesion force and drug release. DSC analysis revealed no interaction between drug and polymers. Ex vivo diffusion studies were carried out using Franz diffusion cell, while bioadhesive properties were evaluated using texture analyzer with porcine buccal mucosa as model tissue. Results revealed that bilayer film containing 4% (w/v) TSX and 0.5% (w/v) CP in the drug layer and 1% (w/v) ethyl cellulose in backing layer demonstrated diffusion of 93.45% through the porcine buccal mucosa. Thus, this study suggests that tamarind seed polysaccharide can act as a potential mucoadhesive polymer for buccal delivery of a highly soluble drug like rizatriptan benzoate. [Copyright &y& Elsevier]

Abstract: Poly(l-lactic acid) (PLLA) chains were grafted on xyloglucan substrates via ring-opening polymerization of the l-lactide monomer. Different parameters such as the nature of the substrate (native or modified xyloglucan) and the substrate/monomer ratios were varied in the synthesis to achieve different lengths of the grafted chains. A range of experimental techniques including infrared spectroscopy and nuclear magnetic resonance were used to characterize the final product. Thermal analysis showed that the glass transition temperature of xyloglucan was decreased from 252°C to 216°C following the grafting of PLLA. The grafting of less hydrophilic chains from xyloglucan also affected the interaction with water: the PLLA-grafted xyloglucan was insoluble in water and the moisture uptake could be decreased by about 30%. Xyloglucan adsorbs strongly to cellulose; therefore such a graft copolymer may improve the compatibility between cellulose fibers and PLLA. The PLLA-grafted xyloglucan may be useful as a novel compatibilizer in fiber-reinforced PLLA composites. [Copyright &y& Elsevier]

Abstract: Oil from the seed of the castor plant (Ricinus communis L.) is an important commodity for a number of industries, ranging from pharmaceuticals to renewable energy resources. However, the seed and subsequent seed meal contain ricin (RCA60), a potent cytotoxin, making it an unusable product for animal feed. In order to investigate the efficiency of reducing the toxicity of the seed meal, a biosensor is proposed by exploring the lectin–carbohydrate binding. A gold electrode was assembled with a film of Xyloglucan (XG) extracted from Hymenaea courbaril L. The analytical response to RCA60 was obtained using a polyclonal antibody against RCA60 conjugated to peroxidase. The current responses were generated by reaction with H2O2 and amplified with hydroquinone as chemical mediator. Voltammetric studies showed that the XG film was tightly bound to the gold electrode. This biosensor allows discriminate lectins in native and denatured forms. The limit of detection of native RCA60 was 2.1μgmL−1. This proposed biosensor showed to be a potential and accurate method for toxicity assessment of the ricin in castor seed meal by simple polysaccharide film-electrode strategy. [Copyright &y& Elsevier]

Abstract: Tamarind seed xyloglucan is an interesting polysaccharide of high molar mass with excellent thermomechanical properties. Several plasticizers were studied in order to facilitate thermal processing and improve toughness (work to fracture) of xyloglucan film materials: sorbitol, urea, glycerol and polyethylene oxide. Films of different compositions were cast and studied by thermogravimetric analysis (TGA), calorimetry (DSC), dynamic mechanical thermal analysis (DMA) and tensile tests. Results are analysed and discussed based on mechanisms and practical considerations. Highly favourable characteristics were found with XG/sorbitol combinations, and the thermomechanical properties motivate further work on this material system, for instance as a matrix in biocomposite materials. [Copyright &y& Elsevier]

Partially de-pectinated grape berry cell walls were sequentially treated with a xyloglucan-specific endoglucanase and with 4 M KOH. The endoglucanase-soluble xyloglucan oligosaccharides (XGO1) consisted predominantly of Glc, Xyl, Gal, and Fuc together with small amounts of Man, Ara and Rha residues that originated from contaminating mannan and pectin. The alkali-soluble xyloglucan (XGO-2) from exocarp and mesocarp was composed of Glc:Xyl:Gal:Fuc in a molar ratios of 4:1.7:1.8:0.4 and 4:1.5:2.5:0.5, respectively. XGO-1 and endoglucanase-treated XGO-2 were shown, by MALDI-TOF-MS for to contain oligosaccharides composed of XXXG-type building units: XXG, XXXG, XXLG or XLXG, XXFG and XLFG. These oligosaccharides were converted to their p-nitrobenzylhydroxyl derivatives and then separated and quantified by HPLC. XXXG, XXFG and XLFG were the quantitatively major oligosaccharides in mesocarp and exocarp cell wall xyloglucan. The distribution of XGO1, extracted with enzymes, is similar between exocarp and mesocarp, while XGO2 present an inversion of the amounts of XXFG and XLFG in skin and pulp. [Copyright &y& Elsevier]

• A KOH-extractable polysaccharide (AS K) was isolated from Abies sibirica foliage. • AS K contained arabinoglucuronoxylans, xyloglucans, glucomannans, pectins and AGPs. • Pectin, xylan, glucan and AGPs were co-eluted in anion-exchange chromatography. • The existence of a covalently bound pectin-xylan-xyloglucan-AGP complex was proposed. Polysaccharide AS K was isolated from the Abies sibirica foliage by extraction with an aqueous KOH solution. AS K was shown to contain structurally different polymers such as arabinoglucuronoxylans, xyloglucans, glucomannans, arabinogalactan-proteins (AGPs). The pectic polysaccharides were also found in the alkaline extract of AS K and were represented by regions of homogalactorunan and rhamnogalactouronan-I whose side sugar chains were made up chiefly of highly branched 1,5-α- l -arabinan. The potential couplings between those polysaccharides were examined. Our studies showed simultaneous elution of pectin, xyloglucans, arabinoglucuronoxylans and AGPs, indicating that pectins can be covalently bound to the other cell-wall polysaccharides. NMR spectroscopy results revealed that the polysaccharides obtained by ion-exchange chromatography almost had no free reducing ends. These findings corroborate the conclusion that pectin, AGPs, glucan and xylan are bound together. The existence of the covalently bound complex of pectin-xylan-xyloglucan-AGP is suggested herein. Pectin and xylan are hypothesized to be covalently linked through RG-I regions. [ABSTRACT FROM AUTHOR]

• Major amounts of glucuronoarabinoxylans (GAX) were obtained from bamboo shoots. • Exhaustive alkaline extraction and alternative extraction with DMSO were performed. • GAX showed acetylation mainly on C3, but also on C2 of some xylose units. • Arabinogalactans and pectins, mixed linkage glucans and xyloglucans were obtained. • The whole cell wall polysaccharide system from this raw material was characterized. Guadua is a genus of woody bamboos, native to the American continent, which comprises economically important species. Cell wall polysaccharides from young shoots of Guadua chacoensis showed glucuronoarabinoxylans (GAX) as the major hemicellulosic components (65%, of the recovered carbohydrates by extraction with aqueous solutions), which were obtained in major quantities with 1 M KOH (molar ratio Xyl:Ara:GlcA, 100:28:8). AGP and pectin polymers, as well as mixed linkage glucans and xyloglucans were present in smaller amounts (16% and 15%, respectively). Alternative extraction of GAX with solutions of DMSO allowed the characterization of alkali labile substituents, in particular, acetyl groups, which were linked mainly to C3 or, to a lesser extent, to C2 of some of the xylose residues. Besides, small amounts of phenolic compounds, released by saponification, were detected, linked to C5 of some α- l -arabinofuranose units. These results could be relevant for their use as a new resource for the food industry. [ABSTRACT FROM AUTHOR]

• Duckweeds promising feedstocks for biofuel production. • Cell walls of duckweed yield mostly apiogalacturonans and xylogalacturonans. • Rhamnogalacturonan I, xylans, xyloglucans, and glucomannans were also observed. • Variation in pectin and hemicellulose abundance is found among species. Rapid growth and easily digestible walls that are naturally low in lignin make the aquatic plant family Lemnaceae, or duckweed, a promising feedstock for biofuel production. Monosaccharide and linkage analysis of cell walls from three species of duckweed: Spirodela polyrhiza , Lemna gibba , and Wolffia australiana showed that apiogalacturonans and/or xylogalacturonans, and smaller amounts of rhamnogalacturonan I, constituted 57%, 51% and 48% of their respective wall mass. Hemicellulosic xylan, xyloglucan, and glucomannan made up lesser amounts wall mass across the three species. Apiose residues were either non-reducing terminal or 3′-linked, but their ratios varied substantially from nearly 1:1 for S. polyrhiza and 2:1 for L. gibba , to 10:1 for W. australiana. These findings will help guide future research to design efficient strategies for disassembly of duckweed cell walls into sugars and uronic acids for conversion of duckweed biomass into usable fuel, and to facilitate extraction of other bioproducts from its polysaccharides. [ABSTRACT FROM AUTHOR]