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The data provided here relate to the research paper “Assessing the complementarity of TD-NMR, solid-state NMR and Dynamic Vapor Sorption in the characterization of polysaccharide-water interactions”. The original data from TD-NMR, ss-NMR and DVS is provided in .dps, topspin and .xls formats respectively, allowing other authors to repeat our processing protocols using different parameters. We also include results obtained by varying the signal treatments. The analysis of these multimodal data have highlighted a variation in polysaccharide-water interactions depending on the type of assembly. These datasets are very useful for discriminating between water bound to polysaccharides and water absorbed or adsorbed into polysaccharide network, a key element in understanding interactions in these assemblies and an essential approach for developing tailor-made polysaccharides-based products.

Solid-state NMR (ssNMR) is a unique technique allowing the study of macromolecular assemblies in their native state without prior modification. The proposed method simplifies the current long and tedious data-acquisition and processing protocols for Variable Contact Time (VCT) ssNMR experiments used in dynamic studies of macromolecular assemblies. Using cellulose nanocrystals as a model for polysaccharide assembly, the acquisition time was reduced by decreasing the number of scans and shortening the recycling time required for the 1H to 13C polarization transfers. • A tenfold reduction in the acquisition time for each kinetic point was achieved while maintaining a good signal to noise ratio. • The processing time for the pseudo-2D solid-state NMR data was also shortened by using signal intensities derived from peak picking rather than the classically-used spectral deconvolution method. • These optimizations enabled the molecular dynamic parameters T1ρH, THH, TCH to be accessed within a day.

Flax (Linum usitatissimum L.) is a plant of industrial importance, its fibres being presently used for high-value textile applications, composite reinforcements as well as natural actuators. Human interest in this fibre-rich plant dates back several millennia, including to Ancient Egypt where flax was used extensively in various quotidian items. While the recent technical developments of flax fibres continue to diversify through scientific research, the historical use of flax also has rich lessons for today. Through careful examination of ancient Egyptian and modern flax fibres, this study aims to conduct a multi-scale characterization from the yarn to the fibre cell wall scale, linking differences in structure and polysaccharide content to the mechanical performance and durability of flax. Here, a multi-scale biochemical study is enriched by scanning electron microscopy and nanomechanical investigations. A key finding is the similarity of cellulose features, crystallinity index and local mechanical performances between ancient and modern fibres. Biochemically speaking, monosaccharides analysis, deep-UV and NMR investigations demonstrate that ancient fibres exhibit less pectins but a similar hemicellulosic content, especially through uronic acids and galactose, suggesting the sensitivity of these non-crystalline components., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The structural arrangement of starch polymers in presence of water is known to impact the functional properties of starchy products. In this study, the hydration of potato starch granules was investigated at the molecular level through various 1 H-> 13 C polarization transfer solid-state Nuclear Magnetic Resonance (ss-NMR) experiments. The impact of increasing the water content from 12.3 % to 45.9 % was assessed using 13 C Cross Polarization Magic Angle Spinning (CPMAS), Variable Contact Time (VCT-CPMAS), Variable Spin Lock (VSL-CPMAS), and T One Rho QUEnching (TORQUE) NMR sequences. Of these, VCT-CPMAS proved to be the most promising. When applied with an optimal number of contact times, it enabled the application of several mathematical models that provided detailed insights into the structuring of protons in the hydrated potato starch granules. At low hydration (12.3 %), the models enabled various structural domains to be distinguished, which we suggest are associated with helical and amorphous structures. At moderate hydration (45.9 %), we tested two fitting models. Two pools of protons were revealed, corresponding to loosely ordered structures on the scale of tens of nanometers. These findings suggest varying water distribution during starch hydration and are likely to indicate variable hydration levels in the multilamellar amorphous structures of starch granules., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)

Characterizing the hygroscopic behavior of macromolecular assemblies is crucial for understanding biological processes as well as to develop tailor-made polysaccharides-based products. In this work, assemblies consisting of nanocelluloses (CNC or CNF) and/or glucomannan in different ratio were studied at different water activity levels, using a multi-analytical approach that combined Dynamic Vapor Sorption (DVS), Time-Domain Nuclear Magnetic Resonance (TD-NMR) and solid-state NMR (ss-NMR). The water retention capacity of the films, as a function of their composition, showed that an enrichment in konjac glucomannan in association with cellulose increased the water absorption capacity but decreased the water retention capacity. In addition, the combination of CNC and glucomannan appears to reduce the water absorption capacity of each polymer. Correlating the findings from the various methods allowed us to propose the use of TD-NMR data for predicting the water retention capacity. These results, summarized in a schematic representation, offer new insights into the organization of water molecules in polysaccharide assemblies in various humidity conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Air-in-oil foams, or oleofoams, have a great potential for food applications as they can at least partially replace animal or hydrogenated fats, without compromising on textural properties. Yet, there are some challenges to tackle before they can largely be implemented for real-life applications. One of those is the lack of data regarding their oxidative stability. This is an important point to consider, as although using oils rich in polyunsaturated fatty acids (PUFAs) is highly desirable from a nutritional perspective, these fatty acids are particularly prone to oxidation, which leads to major degradations of food quality. This work thus aimed to investigate the oxidative stability of oleofoams prepared with omega-3 PUFA-rich vegetable oils (rapeseed or flaxseed oil) and various types of high melting point lipid-based oleogelators (stearic acid, glyceryl monostearate and stearyl alcohol) when incubated at room temperature. The physical structure and stability of the oleofoams was monitored by various techniques (visual observations, microscopy, DSC, NMR, SAXS and WAXS). Lipid oxidation was assessed by combined measurements of primary (conjugated diene hydroperoxides) and secondary (thiobarbituric acid reactive substances - TBARS) products. We found that the oxidative stability of oleofoams was higher compared to that of the corresponding bulk oil. This protective effect was also found when the oil was simply mixed with the oleogelator without incorporation of air bubbles (i.e., forming an oleogel), and was somewhat modulated depending on the type of oleogelator. These results suggest that oleogelators and the structural changes that they induce limit the cascaded propagation of lipid oxidation in oil-continuous matrices, which is promising in the perspective of future applications., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Apple cider juice yield at harvest and after 15 and 30 days of storage durations was studied by analyzing the mechanical properties of fresh and plasmolyzed flesh, water distribution, cell wall polysaccharide composition and organization of the apples; in this study, the apple varieties used were Avrolles, Douce coetligne, Douce moen, Judor, Petit jaune. Juice yield mainly depended on the apple variety and the storage duration. Cellulose organization and cell wall pectin hydration were affected by ripening and are related to fruit firmness. Flesh viscoelastic mechanical properties were not general indications of juice yields. However, these properties helped distinguish the varieties according to flesh damage caused by ice crystals upon freezing. Cell encapsulation of the juice in the flesh contributed to lower yields. The apple variety and harvesting mode are recommended as a means to better control juice yield variations., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Deciphering the determinants of starch digestion from multiple interrelated properties is a challenge that can benefit from multifactorial data analysis. The present study investigated the digestion kinetic parameters (rate, final extent) of size-fractions from four commercial wheat starches with different amylose contents. Each size-fraction was isolated and characterized comprehensively using a large range of analytic techniques (FACE, XRD, CP-MAS NMR, time-domain NMR, DSC…). A statistical clustering analysis applied on the results revealed that the mobility of water and starch protons measured by time-domain NMR was consistently related to the macromolecular composition of the glucan chains and to the ultrastructure of the granule. The final extent of starch digestion was determined by the granule structural features. The digestion rate coefficient dependencies, on the other hand, changed significantly with the range of granule size, i.e. the accessible surface for initial binding of α-amylase. The study particularly showed the molecular order and the chains mobility predominantly limiting or accelerating the digestion rate depending on the accessible surface. This result confirmed the need to differentiate between the surface and the inner-granule related mechanisms in starch digestion studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

To evaluate cellulose interactions with water, 1 H-> 13 C polarization transfer kinetics during Variable Contact Time CP-MAS NMR spectroscopy were studied and modelled using cellulose of different origins. The increase in the temporal resolution of the plot relating signal intensity to contact-time made it possible to compare different physical models for use in fitting the kinetic curve. These models involve combinations of variables, such as proton spin diffusions, that require a better understanding of their physicochemical and structural bases. To that end, hydrogen interactions were modulated by adding water, first by varying cellulose water content, second by exchanging hydroxyl protons with D2O, and last by varying the spinning rate. The results demonstrate that this approach makes it possible to probe interactions of polysaccharides with structural water, as well as to follow the evolution of the proton-proton interactions during hydration through spin diffusion times., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier Ltd.)

Fibre bundles are groups of elementary fibres glued together thanks to the middle lamella, and are the main fraction in plant fibre composites. In this study, relationship between the mechanical properties of flax fibre bundles, chemical composition and cellulose structure were investigated. To do so, a sequential biopolymer extraction was implemented. Fibre bundles were first depectinated by oxalate extraction, and then the hemicelluloses were extracted by LiCl/dimethyl sulfoxide (DMSO) and KOH. The oxalate extract consisted of homogalacturonans and type I rhamnogalacturonans, while the LiCl extract was composed mainly of glucomannans and the KOH extract of xyloglucans. The KOH stage resulted in the appearance of cellulose II in flax bundles. The extraction of pectin and hemicelluloses led to the disappearance of the middle lamella concomitant with a decrease in the tensile Young's modulus and maximum strength. Finally, the fibre bundle composition, ultrastructure and mechanical properties are discussed together in view of the thin middle lamella., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Heteroxylans (HX) from vitreous and floury parts of maize endosperm were isolated. Structural analysis showed a xylan backbone with few unsubstituted xylose residues (<9%) demonstrating the high content in side chains in both fractions. HX from floury endosperm contained more arabinose and galactose than vitreous HX. The mono-substitution rate was 15% higher in the vitreous endosperm HX. Similar amounts of uronic acids were present in both fractions (~7% DM). Galactose in the floury endosperm HX was present exclusively in terminal position. A xylanase preparation solubilized more material from floury (40.5%) than from vitreous endosperm cell walls (15%). This could be a consequence of the structural differences between the two fractions and/or of the impact of structure on the interaction abilities of these fractions with other cell wall polysaccharides. Our study advances the understanding of cell wall polysaccharides in maize endosperm and their role in enzymatic susceptibility of maize grain., (Copyright © 2021. Published by Elsevier Ltd.)

We have studied the growth process of thin polyelectrolyte (PE) films fabricated by the layer-by-layer assembly (LbL) and composed of Dextran sulfate with high (DexS H) and low (DexS L) sulfation rate and poly(allylamine hydrochloride) (PAH). Film growths were monitored by combining Quartz Crystal Microbalance with Dissipation monitoring (QCM-D), Surface Plasmon Resonance (SPR) and Atomic Force Microscopy (AFM). Even though, the two films growth up to 10 bilayers, QCM-D showed that polyelectrolyte pairs do not display similar behaviours. (PAH/DexS H) systems lead to linear growth, i.e. amounts deposited increase both for PAH and DexS H, while the PAH/DexS L pair generated zig-zag shaped asymmetric growth. Film water contents were determined by QCM-D solvent exchange and SPR experiments. DexS L contains less water than DexS H and in agreement with the QCM-D dissipation values that suggest the formation of more rigid films in the case of DexS L than DexS H. Surface morphology investigated by AFM display distinct surface patterns since DexS H form thin films with fibril-like morphology covering all the surface while heterogeneous films with "puddle-like" aggregates were imaged in the case of DexS L. Difference of charge compensation and charge neutralisation between both systems likely lead to dissimilar growth mechanisms that are tentatively proposed in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

To establish a "green" biorefinery extraction of apple pomace pectin, a sequential pretreatment with three natural deep eutectic solvents (NADES, choline chloride (CC): glycerol (G); CC: lactic acid (LA); potassium carbonate (K): G) was used prior to hot water extraction. A synergistic effect of CC:G and CC:LA pretreatments was observed and led to the highest recovery of pectin. The sequential NADES/water extraction process also provided a mean to tailor pectin main structure. It was explained as resulting from ion exchange and individual NADES components effects. The 13 C solid state NMR T 1ρ H and T HH parameters indicated a reorganization of cellulose in the residues following extraction of pectin, notably after alkaline K:G pretreatment/water extraction. Hence, sequential NADES pretreatments/water extraction represents a "green" alternative to mild mineral acid to extract pectin and to tailor its main structures, while the residual pomace can be further sources of valuable compounds and polymers., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Senior individuals can suffer from immunosenescence and novel strategies to bolster the immune response could contribute to healthy ageing. In this double-blind, randomised, controlled pilot trial, we investigated the ability of non-digestible polysaccharide (NPS) preparations to enhance the immune response in a human vaccination model. In total, 239 subjects (aged 50-79 years) were randomised to consume one of five different NPS (yeast β-glucan (YBG), shiitake β-glucan (SBG), oat β-glucan (OBG), arabinoxylan (AX), bacterial exopolysaccharide (EPS)) or control (CTRL) product daily for five weeks. After two weeks of intervention, subjects were vaccinated with seasonal influenza vaccine. The post-vaccination increases in haemagglutination inhibition antibody titres and seroprotection rate against the influenza strains were non-significantly enhanced in the NPS intervention groups compared to CTRL. Specifically, a trend towards a higher mean log 2 fold increase was observed in the AX group (uncorrected p = 0.074) combined with a trend for an increased seroprotection rate, AX group (48.7%) compared to CTRL (25.6%) (uncorrected p = 0.057), for the influenza A H1N1 strain. Subjects consuming AX also had a reduced incidence of common colds compared to CTRL (1 vs. 8; p = 0.029 in Fisher exact test). No adverse effects of NPS consumption were reported. The findings of this pilot study warrant further research to study AX as an oral adjuvant to support vaccine efficacy.

Background: Biomass recalcitrance is governed by various molecular and structural factors but the interplay between these multiscale factors remains unclear. In this study, hot water pretreatment (HWP) was applied to maize stem internodes to highlight the impact of the ultrastructure of the polymers and their interactions on the accessibility and recalcitrance of the lignocellulosic biomass. The impact of HWP was analysed at different scales, from the polymer ultrastructure or water mobility to the cell wall organisation by combining complementary compositional, spectral and NMR analyses., Results: HWP increased the kinetics and yield of saccharification. Chemical characterisation showed that HWP altered cell wall composition with a loss of hemicelluloses (up to 45% in the 40-min HWP) and of ferulic acid cross-linking associated with lignin enrichment. The lignin structure was also altered (up to 35% reduction in β-O-4 bonds), associated with slight depolymerisation/repolymerisation depending on the length of treatment. The increase in [Formula: see text], [Formula: see text] and specific surface area (SSA) showed that the cellulose environment was looser after pretreatment. These changes were linked to the increased accessibility of more constrained water to the cellulose in the 5-15 nm pore size range., Conclusion: The loss of hemicelluloses and changes in polymer structural features caused by HWP led to reorganisation of the lignocellulose matrix. These modifications increased the SSA and redistributed the water thereby increasing the accessibility of cellulases and enhancing hydrolysis. Interestingly, lignin content did not have a negative impact on enzymatic hydrolysis but a higher lignin condensed state appeared to promote saccharification. The environment and organisation of lignin is thus more important than its concentration in explaining cellulose accessibility. Elucidating the interactions between polymers is the key to understanding LB recalcitrance and to identifying the best severity conditions to optimise HWP in sustainable biorefineries., (© 2021. The Author(s).)

Background: The recalcitrance of lignocellulosics to enzymatic saccharification has been related to many factors, including the tissue and molecular heterogeneity of the plant particles. The role of tissue heterogeneity generally assessed from plant sections is not easy to study on a large scale. In the present work, dry fractionation of ground maize shoot was performed to obtain particle fractions enriched in a specific tissue. The degradation profiles of the fractions were compared considering physical changes in addition to chemical conversion., Results: Coarse, medium and fine fractions were produced using a dry process followed by an electrostatic separation. The physical and chemical characteristics of the fractions varied, suggesting enrichment in tissue from leaves, pith or rind. The fractions were subjected to enzymatic hydrolysis in a torus reactor designed for real-time monitoring of the number and size of the particles. Saccharification efficiency was monitored by analyzing the sugar release at different times. The lowest and highest saccharification yields were measured in the coarse and fine fractions, respectively, and these yields paralleled the reduction in the size and number of particles. The behavior of the positively- and negatively-charged particles of medium-size fractions was contrasted. Although the amount of sugar release was similar, the changes in particle size and number differed during enzymatic degradation. The reduction in the number of particles proceeded faster than that of particle size, suggesting that degradable particles were degraded to the point of disappearance with no significant erosion or fragmentation. Considering all fractions, the saccharification yield was positively correlated with the amount of water associated with [5-15 nm] pore size range at 67% moisture content while the reduction in the number of particles was inversely correlated with the amount of lignin., Conclusion: Real-time monitoring of sugar release and changes in the number and size of the particles clearly evidenced different degradation patterns for fractions of maize shoot that could be related to tissue heterogeneity in the plant. The biorefinery process could benefit from the addition of a sorting stage to optimise the flow of biomass materials and take better advantage of the heterogeneity of the biomass.

Kin selection and reciprocation of biological services are distinct theories invoked to explain the origin and evolutionary maintenance of altruistic and cooperative behaviors. Although these behaviors are not considered to be mutually exclusive, the cost-benefit balance of behaving altruistically or cooperating reciprocally and the conditions promoting a switch between such different strategies have rarely been tested. Here, we examine the association between allofeeding, allopreening, and vocal solicitations in wild barn owl ( Tyto alba ) broods under different food abundance conditions: natural food provisioning and after an experimental food supplementation. Allofeeding was performed mainly by elder nestlings (hatching is asynchronous) in prime condition, especially when the cost of forgoing a prey was small (when parents allocated more prey to the food donor and after food supplementation). Nestlings preferentially shared food with the siblings that emitted very intense calls, thus potentially increasing indirect fitness benefits, or with the siblings that provided extensive allopreening to the donor, thus possibly promoting direct benefits from reciprocation. Finally, allopreening was mainly directed toward older siblings, perhaps to maximize the probability of being fed in return. Helping behavior among relatives can therefore be driven by both kin selection and direct cooperation, although it is dependent on the contingent environmental conditions.

Starch, an abundant and low-cost plant-based glucopolymer, has great potential to replace carbon-based polymers in various materials. In order to optimize its functional properties for bioplastics applications chemical groups need to be introduced on the free hydroxyl groups in a controlled manner, so an understanding of the resulting structure-properties relationships is therefore essential. The purpose of this work was to study the multiscale structure of highly-acetylated (degree of substitution, 0.4 < DS ≤ 3) and etherified starches by using an original combination of experimental strategies and methodologies. The molecular structure and substituents repartition were investigated by developing new sample preparation strategies for specific analysis including Asymmetrical Flow Field Flow Fractionation associated with Multiangle Laser Light Scattering, Nuclear Magnetic Resonance (NMR), Raman and Time of Flight Secondary Ion Mass spectroscopies. Molar mass decrease and specific ways of chain breakage due to modification were pointed out and are correlated to the amylose content. The amorphous structuration was revealed by solid-state NMR. This original broad analytical approach allowed for the first time a large characterization of highly-acetylated starches insoluble in aqueous solvents. This strategy, then applied to characterize etherified starches, opens the way to correlate the structure to the properties of such insoluble starch-based materials.

Zein-based filaments containing 20 weight% [Lidocainium][Ibuprofenate] used as a doubly Active Pharmaceutical Ingredient-Ionic Liquid (API-IL) were obtained by extrusion at 130 °C. The plasticizing effect of the active ingredient on the zein amorphous matrix was assessed by differential scanning calorimetry, with a decrease in the glass transition temperature (T g ) from 77 °C, for the raw zein, to 53 °C. After storage under standard conditions (relative humidity 59%, 20 °C) the extrudates were rigid, with a high storage modulus (E') of about 3 GPa at ambient temperature. They had a main mechanical relaxation (T α ) beginning at 55 °C, leading to their flowing at temperatures above 130 °C, as determined by dynamic mechanical analysis, with E' below 1 MPa and tan δ above 1. Their structure was evaluated by wide angle X-ray scattering and NMR analysis was used to evaluate the API-IL stability after thermomechanical processing. Release experiments performed under simulated physiological conditions on filaments evidenced a release of 85% after 7 days immersion. These results demonstrate the advantage of using an API-IL as plasticizer of a resorbable biopolymer. The resulting material can be shaped by a continuous thermomechanical process and used as a drug delivery system.

The viscoelastic mechanical properties are important quality traits for fleshy fruit uses. The contribution of cell wall polysaccharides chemistry and organization on their variability was studied in six varieties of apple. Correlation between damping and storage modulus of plasmolyzed tissue distinguished better apple varieties on their viscoelasticity than fresh samples. Galactose, arabinose and uronic acids correlated positively with the storage modulus of fresh apple samples (E' f ). These corresponded to 4-linked galactan but no specific arabinose linkage. Galacturonic acid branched on O-3 and terminal rhamnose correlated negatively with E' f . These correlations formed two groups of fruit except for branched methyl-esterified galacturonic. Solid-state 13 C NMR spectroscopy analyses showed that E' f correlated negatively with cellulose C4 T 1ρ H relaxation and positively with pectin methyl esters T HH proton diffusion. The results point to the key roles of pectin structure and hydration and cellulose microfibrils distribution on apple mechanical properties., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

We report the complete conversion of inulin in gas/liquid media by a dielectric barrier discharge plasma at atmospheric pressure. Depending on the plasma treatment time (from 1 to 30 min) and the chemical nature of the gases (air, oxygen, nitrogen), it was possible to depolymerize inulin into fructo-oligosaccharides with a degree of polymerization under 5 or to achieve a total conversion of inulin into its two monomeric constituents, fructose and glucose in 20 min, without any degradation products. Combined results from liquid chromatography (HPLC), solid state Nuclear Magnetic Resonance (ssNMR) and mass spectroscopy revealed that the breakage of the β 1-4-bridged oxygen occurs by an acidic attack, following the oxidation of the polymer. Infrared spectroscopy revealed the oxidation and breakage of the polymer and also adsorption of nitrate species. Non thermal plasma treatment appears as a promising technology for the efficient production of mono and oligosaccharides from various sources for the added value molecules in food and pharmaceutical application domains., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Different amounts of cellulose nanocrystals (CNCs) were added to glycerol-plasticized thermoplastic starch (TPS) to obtain bio-based nanocomposites. First, nanocomposites are prepared by extrusion and their structure is studied at different scales using WAXS (Wide Angle X-ray Scattering) and solid-state NMR (Nuclear Magnetic Resonance) for local/crystalline organization, AF4 (Asymmetrical Flow Field-Flow Fractionation) for molecular weight and chain length, and SEM (Scanning Electron Microscopy) for the morphology at a larger scale. Then, relevant mechanical properties and behavior in physiological conditions (swelling, enzymatic degradation) are characterized. The results show that the incorporation of cellulose nanocrystals up to 2.5 wt% causes a mechanical reinforcement as determined by DMTA (Dynamic Mechanical Thermal Analysis) and reduces the swelling and the enzymatic degradation of the materials compared to reference TPS. This could be linked to the formation of starch-cellulose hydrogen and hydroxyl bonds. Conversely, above 5 wt% CNC content nanocrystals seem to aggregate which in turn worsens the behavior in physiological conditions., (Copyright © 2019. Published by Elsevier Ltd.)

In wheat endosperm, mannan, is poorly documented. Nevertheless, this hemicellulosic polysaccharide might have a determinant role in wheat grain development since, in Arabidopsis thaliana, mutants with a reduced amount of mannan show an altered seed development. In order to gain knowledge about mannan in wheat, we have determined its biochemical structure in wheat endosperm where mannose content is about 0.2% (dry weight basis). We developed a method of enzymatic fingerprinting and isolated mannan-enriched fractions to decipher its fine structure. Although it is widely accepted that the class of mannan present in grass cell walls is glucomannan, our data indicate that, in wheat endosperm, this hemicellulose is only represented by short unsubstituted chains of 1,4 linked D-mannose residues and is slightly acetylated. Our study provides information regarding the interactions of mannan with other cell wall components and help to progress towards the understanding of monocot cell wall architecture and the mannan synthesis in wheat endosperm., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Flax retting is a major bioprocess in the cultivation and extraction cycle of flax fibres. The aim of the present study is to improve the understanding of the evolution of fibre properties and ultrastructure caused by this process at the plant cell wall scale. Initially, investigations of the mechanical performances of the flax cell walls by Atomic Force Microscopy (AFM) in Peak Force mode revealed a significant increase (+33%) in the cell wall indentation modulus with retting time. Two complementary structural studies are presented here, namely using X-Ray Diffraction (XRD) and solid state Nuclear Magnetic Resonance (NMR). An estimation of the cellulose crystallinity index by XRD measurements, confirmed by NMR, shows an increase of 8% in crystallinity with retting mainly due to the disappearance of amorphous polymer. In addition, NMR investigations show a compaction of inaccessible cell wall polymers, combined with an increase in the relaxation times of the C4 carbon. This densification provides a structural explanation for the observed improvement in mechanical performance of the secondary wall of flax fibres during the field retting process., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Alkaline treatment is a common step largely used in the industrial extraction of agar, a phycocolloid obtained from red algae such as Gelidium sesquipedale . The subsequent residue constitutes a poorly valorized by-product. The present study aimed to identify low-molecular-weight compounds in this alkaline waste. A fractionation process was designed in order to obtain the oligosaccharidic fraction from which several glycerol-galactosides were isolated. A combination of electrospray ion (ESI)-mass spectrometry, ¹H-NMR spectroscopy, and glycosidic linkage analyses by GC-MS allowed the identification of floridoside, corresponding to Gal-glycerol, along with oligogalactosides, i.e., (Gal) 2⁻4 -glycerol, among which α-d-galactopyranosyl-(1→3)-β-d-galactopyranosylα1-2⁻glycerol and α-d-galactopyranosyl-(1→4)-β-d-galactopyranosylα1-2⁻glycerol were described for the first time in red algae.

Background: Biomass recalcitrance to enzymatic hydrolysis has been assigned to several structural and chemical factors. However, their relative importance remains challenging to evaluate. Three representative biomass species (wheat straw, poplar and miscanthus) were submitted to four standard pretreatments (dilute acid, hot water, ionic liquid and sodium chlorite) in order to generate a set of contrasted samples. A large array of techniques, including wet chemistry analysis, porosity measurements using NMR spectroscopy, electron and fluorescence microscopy, were used in order to determine possible generic factors of biomass recalcitrance., Results: The pretreatment conditions selected allowed obtaining samples displaying different susceptibility to enzymatic hydrolysis (from 3 up to 98% of the initial glucose content released after 96 h of saccharification). Generic correlation coefficients were calculated between the measured chemical and structural features and the final saccharification rates. Increases in porosity displayed overall strong positive correlations with saccharification efficiency, but different porosity ranges were concerned depending on the considered biomass. Lignin-related factors displayed highly negative coefficients for all biomasses. Lignin content, which is likely involved in the correlations observed for porosity, was less detrimental to enzymatic hydrolysis than lignin composition. Lignin influence was highlighted by the strong negative correlation with fluorescence intensity which mainly originates from monolignols in mature tissues., Conclusions: Our results provide a better understanding of the factors responsible for biomass recalcitrance that can reasonably be considered as generic. The correlations with specific porosity ranges are biomass species-dependent, meaning that enzymes cocktails with fitted enzyme size are likely to be needed to optimise saccharification depending on the biomass origin. Lignin composition, which probably influences its structure, is the most important parameter to overcome to enhance enzymes access to the polysaccharides. Accordingly, fluorescence intensity was found to be a rapid and simple method to assess recalcitrance after pretreatment.

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., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Lytic polysaccharide monooxygenases (LPMOs) are a class of powerful oxidative enzymes that breakdown recalcitrant polysaccharides such as cellulose. Here we investigate the action of LPMOs on cellulose fibers. After enzymatic treatment and dispersion, LPMO-treated fibers show intense fibrillation. Cellulose structure modifications visualized at different scales indicate that LPMO creates nicking points that trigger the disintegration of the cellulose fibrillar structure with rupture of chains and release of elementary nanofibrils. Investigation of LPMO action using solid-state NMR provides direct evidence of modification of accessible and inaccessible surfaces surrounding the crystalline core of the fibrils. The chains breakage likely induces modifications of the cellulose network and weakens fibers cohesion promoting their disruption. Besides the formation of new initiation sites for conventional cellulases, this work provides the first evidence of the direct oxidative action of LPMOs with the mechanical weakening of the cellulose ultrastructure. LPMOs can be viewed as promising biocatalysts for enzymatic modification or degradation of cellulose fibers.

The water status of Medicago truncatula Gaertn. seed was followed by low-field NMR relaxometry during germination with and without oryzalin or fusicoccin used as growth modulators. T1 and T2 relaxation times and proportions P1 and P2 were determined on fresh, frozen, and freeze-thawed samples to characterize changes in water dynamics and compartmentation and in the nonfreezing water fraction. The results demonstrate that low-field NMR relaxometry allowed differentiating germination phases and events occurring during them as well as perturbations related to the presence of growth modulators. The results provide clear evidence that the classical multicomponent relaxation interpretation cannot directly relate T2 components and morphological compartments in biological tissue.

Probiotics represent a potential strategy to influence the host's immune system thereby modulating immune response. Lipoteichoic Acid (LTA) is a major immune-stimulating component of Gram-positive cell envelopes. This amphiphilic polymer, anchored in the cytoplasmic membrane by means of its glycolipid component, typically consists of a poly (glycerol-phosphate) chain with D-alanine and/or glycosyl substitutions. LTA is known to stimulate macrophages in vitro, leading to secretion of inflammatory mediators such as Nitric Oxide (NO). This study investigates the structure-activity relationship of purified LTA from three probiotic Bacillus strains (Bacillus cereus CH, Bacillus subtilis CU1 and Bacillus clausii O/C). LTAs were extracted from bacterial cultures and purified. Chemical modification by means of hydrolysis at pH 8.5 was performed to remove D-alanine. The molecular structure of native and modified LTAs was determined by (1)H NMR and GC-MS, and their inflammatory potential investigated by measuring NO production by RAW 264.7 macrophages. Structural analysis revealed several differences between the newly characterized LTAs, mainly relating to their D-alanylation rates and poly (glycerol-phosphate) chain length. We observed induction of NO production by LTAs from B. subtilis and B. clausii, whereas weaker NO production was observed with B. cereus. LTA dealanylation abrogated NO production independently of the glycolipid component, suggesting that immunomodulatory potential depends on D-alanine substitutions. D-alanine may control the spatial configuration of LTAs and their recognition by cell receptors. Knowledge of molecular mechanisms behind the immunomodulatory abilities of probiotics is essential to optimize their use.

Cell wall composition, pectin, and hemicellulose fine structure variation were assessed in peach and related genotypes with contrasted texture and fruit shape. Cell walls were prepared from four commercial peaches, eight genotypes from the Jalousia × Fantasia peach cross, and six genotypes from the Earlygold peach × Texas almond cross. Sugar composition was determined chemically while fine structure of homogalacturonan pectin and xyloglucan hemicellulose were assessed by coupling pectin lyase and glucanase degradation, respectively, with MALDI-TOF MS analysis of the degradation products. The results indicate clear compositional and structural differences between the parents and their related genotypes on the basis of pectin versus cellulose/hemicellulose content and on the fine structure of homogalacturonan and xyloglucan. A relation between methyl- and acetyl-esterification of pectin with fruit shape is revealed in the Fantasia × Jalousia peach genotypes.