Physicochemical properties and structural characterization by two-dimensional NMR spectroscopy of wheat β-D-glucan—comparison with other cereal β-D-glucans

A novel polysaccharide from Citrus aurantium L.: Structural properties and antitumor activities in vitro and invivo

A novel cold-water-soluble polysaccharide (CALP-1-1) was isolated and purified from Citrus aurantium L. Besides determining its in vitro and in vivo anti-tumor activities, its structure was characterised. The results reveal that CALP-1-1 mainly consists of Rha, Ara, Gal, GalA, and GlcA (molar ratio, 1:14.56:19.27:2.27:1.29) with three main linkages. Its average molecular weight was 2.04 × 103 kDa. Moreover, the triple helix structure of CALP-1-1 was proved by Congo-red and circular dichroism (CD). The in vitro experimental results demonstrate that CALP-1-1 significantly inhibited the proliferation of HepG2 cells with typical apoptotic features by inducing cell cycle arrest in the S phase. Furthermore, in vivo anti-tumor experiments suggest that CALP-1-1 could induce H22 solid tumor cells apoptosis and exhibit anti-tumor effects by protecting immune organs and intensifying the secretion of immune cells (macrophages, lymphocytes and NK cells). In conclusion, CALP-1-1 might be a promising component for cancer treatment.

Synergistic anti-inflammatory effects of Ganoderma lucidum polysaccharide and ganoderic acid A on LPS-induced RAW264.7 cells by inhibition of TLR4/NF-κB activation

Ganoderma lucidum, a food-grade medicinal mushroom, is rich in biologically active components that offer significant health benefits. This study investigated the synergistic anti-inflammatory effects of Ganoderma lucidum polysaccharide (GLP-1) and ganoderic acid A (GAA) in RAW264.7 cells. GLP-1 was a low molecular weight β-D-glucan with an alternating backbone structure formed by →3)-β-D-Glcp-(1 → and →4)-β-D-Glcp-(1 → linkages. Notably, significant synergistic effects were observed at a mass concentration ratio of GAA: GLP-1 of 1:4. The combination of GLP-1 and GAA more effectively inhibited the production of NO, pro-inflammatory cytokines (IL-6, IL-1β and TNF-α) and reactive oxygen species (ROS) compared to each component alone. Additionally, the combination increased anti-inflammatory cytokine levels (IL-10) and restored mitochondrial membrane potential. RT-qPCR and Western blot results suggested that GLP-1 and GAA may co-target the TLR4/NF-κB signaling pathways to achieve their synergistic anti-inflammatory effects. These findings provide valuable insights for future synergistic application of active ingredients from natural products.

From root to leaf: Cell walls of the halophytic grass Distichlis laxiflora comprise highly substituted glucuronoarabinoxylans

Halophytic plants develop their life cycle in high salinity conditions. Several physiological responses explain this, but little was explored regarding the role of their cell walls (CW). In grasses, which have small amounts of pectins, hemicelluloses should show the greatest effects of salt stress. In this work, CW from roots, shoots, and leaves from Distichlis laxiflora collected in spring (the regrowth period) in halophytic (H) and mesophytic (M) meadows were studied. This is a first approach to the CW of halophytic grasses, with an evaluation of differences between organs, and between sites with distinct salinity. The main alkaline fractions contain glucuronoarabinoxylans (GAX) as major component, followed by small amounts of pectins and β-glucans. Analysis of their composition showed that polysaccharides from leaves of both sites differ little, while greater differences (involving xylose, glucuronic acid, glucose, and arabinose) are found within roots. If the alkaline extracts and the final residue are considered together, both leaves and shoots have ≥50% of GAX and 20-30% cellulose in their CW, while roots show similar amounts of GAX and cellulose (35-40% of each). Additionally, GAX from roots show a higher degree of substitution with glucuronic acid, regarding the other organs and GAX reported for other grasses, and considerable amounts of 4-linked xylopyranose residues disubstituted with single ramifications of α-L-arabinofuranose. As the first barrier in contact with soil salinity, roots respond through the modification of the classical structure of GAX, which would be more suitable to entrap Na+ ions, by the presence of more negative charges.

Yellow mustard gum: pilot-scale production and characterization

BACKGROUND

Yellow mustard gum (YMG), which is extracted from the mucilaginous part of yellow mustard bran, has been considered an emerging natural hydrocolloid gum but lacks commercial development and production. To promote the commercial utilization of YMG, this study developed a pilot-scale YMG production protocol in an economic and environmentally friendly way to produce a clean-label YMG product. This YMG produced at pilot scale (YMW) was characterized in terms of chemical composition, rheological properties, and interaction with a commercial gum, κ-carrageenan, and was compared with purified YMG through ethanol precipitation (YME).

RESULTS

The protocol processed up to 100 L of raw material with zero solvent and a minimal number of steps and showed strong quasi-industrial potential. The YMW showed a similar chemical composition as YME. However, the YMW contained a slightly lower amount of carbohydrate and a much larger amount of ash and potassium than the YME. The rheological results concluded that both the YMW and YME solutions exhibited shear-thinning flow behavior and a weak gel, with YME showing higher viscosity and stronger gel structure. Most interestingly, YMW could form unpourable gels when blended with native κ-carrageenan whereas YME barely achieved this despite the equivalent total gum concentration.

CONCLUSION

This study demonstrated the feasibility of YMG production at a large scale with economic and green procedures and discovered its new functionality for commercial utilization. The gelling ability of YMG could provide it with wider applications as a result of a new potential synergistic combination. All this information should accelerate the process of full commercialization of YMG as a clean-label functional ingredient. © 2024 His Majesty the King in Right of Canada. Journal of The Science of Food and Agriculture © 2024 Society of Chemical Industry. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

A novel substitution pattern in glucuronoarabinoxylans from woody bamboos

(1 → 4)-β-D-Xylans are the second most abundant plant biopolymers on Earth after cellulose. Although their structures have been extensively studied, and industrial applications have been found for them and their derivatives, they are still investigated due to the diversity of their structures and uses. In this work, hemicellulose fractions obtained previously with 1 M KOH from two species of woody bamboos, Phyllostachys aurea and Guadua chacoensis, were purified, and the structures of the glucuronoarabinoxylans (GAX) were studied by chemical and spectroscopic methods. In both cases, major amounts of α-L-arabinofuranose residues were linked to C3 of the xylose units of the backbone, and also α-D-glucuronic acid residues and their 4-O-methyl-derivatives were detected in minor quantities, linked to C2 of some xylose residues. Methylation analysis of the carboxyl-reduced derivative from GAX from P. aurea indicated the presence of terminal and 5-linked arabinofuranose units. NMR spectroscopy showed the presence of disaccharidic side chains of 5-O-α-l-arabinofuranosyl-L-arabinofuranose for the GAX from P. aurea, while for those of G. chacoensis, only single side chains were found. To the best of our knowledge, this disaccharide was not found before as side chain of xylans.

Bioinspired mechanically stable all-polysaccharide based scaffold for photosynthetic production

We demonstrate the construction of water-stable, biocompatible and self-standing hydrogels as scaffolds for the photosynthetic production of ethylene using a bioinspired all-polysaccharidic design combining TEMPO-oxidised cellulose nanofibers (TCNF) and a cereal plant hemicellulose called mixed-linkage glucan (MLG). We compared three different molecular weight MLGs from barley to increase the wet strength of TCNF hydrogels, and to reveal the mechanisms defining the favourable interactions between the scaffold components. The interactions between MLGs and TCNF were revealed via adsorption studies and interfacial rheology investigations using quartz crystal microbalance with dissipation monitoring (QCM-D). Our results show that both the MLG solution stability and adsorption behaviour did not exactly follow the well-known polymer adsorption and solubility theories especially in the presence of co-solute ions, in this case nitrates. We prepared hydrogel scaffolds for microalgal immobilisation, and high wet strength hydrogels were achieved with very low dosages of MLG (0.05 wt%) to the TCNF matrix. The all-polysaccharic biocatalytic architectures remained stable and produced ethylene for 120 h with yields comparable to the state-of-the-art scaffolds. Due to its natural origin and biodegradability, MLG offers a clear advantage in comparison to synthetic scaffold components, allowing the mechanical properties and water interactions to be tailored.

Genetic Approaches to Increase Arabinoxylan and β-Glucan Content in Wheat

Wheat is one of the three staple crops feeding the world. The demand for wheat is ever increasing as a relatively good source of protein, energy, nutrients, and dietary fiber (DF) when consumed as wholemeal. Arabinoxylan and β-glucan are the major hemicelluloses in the cell walls and dietary fiber in wheat grains. The amount and structure of DF varies between grain tissues. Reducing post-prandial glycemic response as well as intestinal transit time and contribution to increased fecal bulk are only a few benefits of DF consumption. Dietary fiber is fermented in the colon and stimulates growth of beneficial bacteria producing SCFA, considered responsible for a wide range of health benefits, including reducing the risk of heart disease and colon cancer. The recommended daily intake of 25-30 g is met by only few individuals. Cereals cover nearly 40% of fiber in the Western diet. Therefore, wheat is a good target for improving dietary fiber content, as it would increase the fiber intake and simultaneously impact the health of many people. This review reflects the current status of the research on genetics of the two major dietary fiber components, as well as breeding approaches used to improve their quantity and quality in wheat grain.

Functional and Nutritional Characteristics of Natural or Modified Wheat Bran Non-Starch Polysaccharides: A Literature Review

Wheat bran (WB) consists mainly of different histological cell layers (pericarp, testa, hyaline layer and aleurone). WB contains large quantities of non-starch polysaccharides (NSP), including arabinoxylans (AX) and β-glucans. These dietary fibres have long been studied for their health effects on management and prevention of cardiovascular diseases, cholesterol, obesity, type-2 diabetes, and cancer. NSP benefits depend on their dose and molecular characteristics, including concentration, viscosity, molecular weight, and linked-polyphenols bioavailability. Given the positive health effects of WB, its incorporation in different food products is steadily increasing. However, the rheological, organoleptic and other problems associated with WB integration are numerous. Biological, physical, chemical and combined methods have been developed to optimise and modify NSP molecular characteristics. Most of these techniques aimed to potentially improve food processing, nutritional and health benefits. In this review, the physicochemical, molecular and functional properties of modified and unmodified WB are highlighted and explored. Up-to-date research findings from the clinical trials on mechanisms that WB have and their effects on health markers are critically reviewed. The review points out the lack of research using WB or purified WB fibre components in randomized, controlled clinical trials.

EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA Panel), Turck D, Bohn T, Castenmiller J, De Henauw S, Hirsch‐Ernst KI, Maciuk A, Mangelsdorf I, McArdle HJ, Naska A, Pelaez C, Pentieva K, Siani A, Thies F, Tsabouri S, Vinceti M, Aguilera Gómez M, Cubadda F, Frenzel T, Heinonen M, Prieto Maradona M, Marchelli R, Neuhäuser‐Berthold M, Poulsen M, Schlatter JR, van Loveren H, Ackerl R, Knutsen HK. Safety of paramylon as a novel food pursuant to Regulation (EU) 2015/2283

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on paramylon as a novel food (NF) pursuant to Regulation (EU) 2015/2283. Paramylon is a linear, unbranched beta-1,3-ᴅ-glucan polymer that is isolated from the single-cell microalga Euglena gracilis. The NF consists of at least 95% beta-glucan and minor amounts of protein, fat, ash and moisture. The applicant proposed to use the NF in food supplements, as a food ingredient added to a number of food categories and in foods for total diet replacement for weight control. In 2019, E. gracilis was attributed the qualified presumption of safety (QPS) status with the qualification 'for production purposes only', which includes food products based on microbial biomass of the microalga. Based on the information provided, E. gracilis is not expected to survive the manufacturing process. The submitted toxicity studies did not raise safety concerns. No adverse effects were observed in the subchronic toxicity studies, up to the highest dose tested, i.e. 5,000 mg NF/kg body weight per day. In view of the QPS status of the source of the NF, supported by the manufacturing process, compositional data and lack of toxicity observed in the toxicity studies, the Panel has no safety concerns and concludes that the NF, i.e. paramylon, is safe under the proposed uses and use levels.

Effect of a regular consumption of traditional and roasted oat and barley flakes on blood lipids and glucose metabolism-A randomized crossover trial

Background

Regular consumption of the soluble dietary fiber β-glucan is associated with decreased total cholesterol (TC), low-density lipoprotein (LDL) cholesterol and blood glucose. Barley and oat flakes as natural sources of β-glucan were roasted to improve sensory quality. The aim of this study was to investigate whether roasting of barley and oat flakes changes the physiological impact of the β-glucan-rich flakes on glucose and lipid metabolism.

Method

A five-armed randomized crossover trial design was used. The intervention study was conducted from May 2018 to May 2019 and included 32 healthy subjects with moderately increased LDL cholesterol (≥2.5 mmol/L). During the 3-week intervention periods, 80 g of roasted or traditional barley or oat flakes, or four slices of white toast bread per day were consumed for breakfast. At the start and the end of each intervention, fasting and postprandial blood was taken. The intervention periods were separated by 3-week wash-out periods.

Results

During the interventions with the cereal flakes, TC and LDL cholesterol concentrations were significantly reduced compared to baseline values by mean differences of 0.27-0.33 mmol/L and 0.21-0.30 mmol/L, respectively (p < 0.05), while high-density lipoprotein (HDL) cholesterol was only reduced after the intervention with barley flakes (p < 0.05). After the intervention period with toast, TC and HDL cholesterol increased (p < 0.05). The fasting levels of triglycerides, fasting blood glucose and insulin did not change in any group. The effects of traditional and roasted varieties on blood lipids did not differ between the groups.

Conclusion

The regular consumption of traditional or roasted barley and oat flakes contributes to the management of cardiovascular diseases by improving TC and LDL cholesterol.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT03648112, identifier NCT03648112.

Structure, stability, antioxidant activity, and controlled-release of selenium nanoparticles decorated with lichenan from Usnea longissima

Selenium nanoparticles (SeNPs) have attracted widespread attention, but the poor water dispersibility restricted their applications seriously. Herein, Usnea longissima lichenan decorated selenium nanoparticles (L-SeNPs) were constructed. The formation, morphology, particle size, stability, physicochemical characteristics, and stabilization mechanism of L-SeNPs were investigated via TEM, SEM, AFM, EDX, DLS, UV-Vis, FT-IR, XPS, and XRD. The results indicated that the L-SeNPs displayed orange-red, amorphous, zero-valent, and uniform spherical nanoparticles with an average diameter of 96 nm. Due to the formation of CO⋯Se bonds or the hydrogen bonding interaction (OH⋯Se) between SeNPs and lichenan, L-SeNPs exhibited better heating and storage stability, which kept stable for more than one month at 25 °C in an aqueous solution. The decoration of the SeNPs surface with lichenan endowed the L-SeNPs with superior antioxidant capability, and their free radicals scavenging ability exhibited in a dose-dependent manner. Furthermore, L-SeNPs showed excellent selenium controlled-release performance. In simulated gastric liquids, selenium release kinetics from L-SeNPs followed the Linear superimposition model, which was governed by the polymeric network retardation of macromolecular, while in simulated intestinal liquids, it was well fitted to the Korsmeyer-Peppas model and followed a Fickian mechanism controlled by diffusion.

Effects of diet hulless barley and beta-glucanase levels on ileal digesta soluble beta-glucan molecular weight and carbohydrate fermentation in laying hens

Exogenous β-glucanase (BGase) improves nutrient digestibility and production performance in laying hens fed barley-based diets, but the effect of enzyme and the dosage on β-glucan depolymerization and fermentation in the gastrointestinal tract is poorly understood. The objectives of the study were to determine the effects of hulless barley (HB) and BGase levels on digestive tract β-glucan depolymerization and fermentation in laying hens. A total of 108 Lohman-LSL Lite hens were housed in cages and fed 2 levels of HB (CDC Fibar; 0 and 73%) by substituting wheat in the diet and graded levels of BGase (Econase GT 200 P from ABVista; 0, 0.01 and 0.1% – 0, 20,000, and 200,000 BU/kg) in a 2 × 3 factorial arrangement. Birds were fed experimental diets for 8 weeks, starting at 35 wk of age. Digestive tract samples were collected at the end of the experiment. Statistical significance was set at P ≤ 0.05. Beta-glucan peak molecular weight was lower with the 0.1 compared to both 0 and 0.01% BGase levels, whereas weight average molecular weight was lower with the 0.1 compared to 0% BGase for 73% HB. The maximum molecular weight for the smallest 10% β-glucan molecules decreased with the increasing BGase. Overall, β-glucan molecular weight in the ileum was higher when the birds were given 73 in comparison to 0% HB diets. Total and major short chain fatty acids (SCFA) in the ileum were lower with 0.1 and 0.01 (except propionic acid) compared to 0% BGase in the birds fed 73% HB, but not 0% HB. Interactions between the main effects were found for the cecal acetic and isobutyric acids. In conclusion, exogenous BGase depolymerized high molecular weight β-glucan in HB and wheat. The effects of HB and BGase on carbohydrate fermentation were not apparent, although it appears ileal SCFA concentrations were lower with increasing levels of BGase.

Hulless barley and β-glucanase affect ileal digesta soluble beta-glucan molecular weight and digestive tract characteristics of coccidiosis-vaccinated broilers

Exogenous β-glucanase (BGase) in barley-based feed has been shown to reduce digesta viscosity in chickens, and thereby improve performance. Less well studied is the potential for BGase to convert barley β-glucan into low molecular weight carbohydrates, which might influence digestive tract function and enteric disease. Coccidiosis-vaccinated broiler chickens were fed graded levels of hulless barley (HB) and BGase to determine their effects on β-glucan depolymerization and digestive tract characteristics. Broilers were fed high β-glucan HB (0%, 30% and 60% replacing wheat) and BGase (0%, 0.01% and 0.1%) in a 3 × 3 factorial arrangement. A total of 5,346 broilers were raised in litter floor pens and vaccinated for coccidiosis on d 5. Each treatment was assigned to 1 pen in each of 9 rooms. The significance level was set at P ≤ 0.05. At both 11 and 33 d of broiler ages, peak molecular weight of β-glucan in ileal digesta decreased with increasing BGase for 30% and 60% HB. The maximum molecular weight for the smallest 10% β-glucan molecules (MW-10%) decreased with BGase at both ages for 30% and 60% HB; for birds fed 0% HB, only 0.1% BGase decreased MW-10%. The 0.1% BGase increased caecal short chain fatty acids (SCFA) compared to the 0.01% BGase at d 11 only for the 60% HB. Ileal pH increased with increasing HB and BGase at d 11 and 33. Caecal pH was lower for 0.1% BGase than 0% BGase for 60% HB at d 11. Relative mRNA expression of interleukin 6 (IL-6) and IL-8 in the ileum increased with 0.1% BGase at d 11 and 33, respectively, whereas expression of ileal mucin 2 (MUC2) decreased with 0.1% BGase at d 33. In the caeca, interactions between HB and BGase were significant for monocarboxylate transporter 1 (MCT1) and mucin 5AC (MUC5 AC) on d 11, but no treatment effects were found at d 33. In conclusion, BGase depolymerized high molecular weight β-glucan in HB in a dose-dependent manner. Hulless barley and BGase did not increase SCFA concentrations (except for 60% HB with 0.1% BGase at d 11) and caused minor effects on digestive tract histomorphological measurements and relative mRNA gene expression.

The detection, purity and structural properties of partially soluble mushroom and cereal β-D-glucans: A solid-state NMR study

β-D-glucans are proposed to have many health benefits. It is therefore important to have methods which can distinguish these from other carbohydrates present in natural products, as well as giving glucan content and structural information. Correlations between features in the CP/MAS spectra of β-D-glucans and enzyme assay determined β-D-glucan content were generally found to be poor. The β-D-glucan in dry and hydrated forms of the mushroom Ganoderma lucidum was investigated in detail by spectral peak fitting to the anomeric carbon C1 region in CP/MAS NMR spectra. Hydrated samples gave spectra with enhanced resolution and suggested that a clear distinction between β-D-glucans and other carbohydrates could be possible in the anomeric carbon C1 region. Chemical shift values for a range of carbohydrate polymers, which can be found alongside β-D-glucans, as well as the values for various linkages are given. Contamination by other carbohydrates and buffer salts is discussed.

A review of NMR analysis in polysaccharide structure and conformation: Progress, challenge and perspective

Nuclear magnetic resonance (NMR) has been widely used as an analytical chemistry technique to investigate the molecular structure and conformation of polysaccharides. Combined with 1D spectra, chemical shifts and coupling constants in both homo- and heteronuclear 2D NMR spectra are able to infer the linkage and sequence of sugar residues. Besides, NMR has also been applied in conformation, quantitative analysis, cell wall in situ, degradation, polysaccharide mixture interaction analysis, as well as carbohydrates impurities profiling. This review summarizes the principle and development of NMR in polysaccharides analysis, and provides NMR spectra data collections of some common polysaccharides. It will help to promote the application of NMR in complex polysaccharides of biochemical interest, and provide valuable information on commercial polysaccharide products.

Quality measurements of cuiabana-type pork sausages added with brewing by-product flours

The objective of this study was to evaluate the replacement of part of the pork from Cuiabana sausage by a brewery by-product on the physicochemical and microbiological properties during storage. Brewery by-product (BW) concentration influenced sausage colouration, with reduced luminosity, L*: 52.060 in the 6% (w/w) treatment compared to the 0% treatment controls (L*: 63.956). Titratable acidity showed higher (1.162 g/100 g) compared to the 0% treatment controls (1.093 g/100 g) of lactic acid. Proteins and total enzymatic fibers increased, 19.068 and 9.233 g/100 g of sample respectively. It was observed that the by-product did not interfere in the oxidation of the lipids and the best model to describe the oxidation of lipids is Van Bertalanffy model (P < 0.05). Escherichia coli and Staphylococcus sp. levels were within the prescribed limits and Listeria monocytogenes colonies were observed. The addition of by-products had no interference on the formation of oxidation compounds in the sausage and has increased fiber content.

The Structural Characteristics and Biological Activities of Intracellular Polysaccharide Derived from Mutagenic Sanghuangporous sanghuang Strain

Sanghuangporous sanghuang is a rare medicinal fungus which contains polysaccharide as the main active substance and was used to treat gynecological diseases in ancient China. The intracellular polysaccharide yield of S. sanghuang was enhanced by the strain A130 which was screened from mutant strains via atmospheric and room temperature plasma (ARTP) mutagenesis. The objective of this research was to investigate the effects of ARTP mutagenesis on structural characteristics and biological activities of intracellular polysaccharides from S. sanghuang. Six intracellular polysaccharide components were obtained from S. sanghuang mycelia cultivated by the mutagenic strain (A130) and original strain (SH1), respectively. The results revealed that the yields of polysaccharide fractions A130-20, A130-50 and A130-70 isolated from the mutagenic strain fermentation mycelia were significantly higher than those of the original ones by 1.5-, 1.3- and 1.2-fold, and the clear physicochemical differences were found in polysaccharide fractions precipitated by 20% ethanol. A130-20 showed a relatively expanded branching chain with higher molecular weight and better in vitro macrophage activation activities and the IL-6, IL-1, and TNF-α production activities of macrophages were improved by stimulation of A130-20 from the mutagenic strain. This study demonstrates that ARTP is a novel and powerful tool to breed a high polysaccharide yield strain of S. sanghuang and may, therefore, contribute to the large-scale utilization of rare medicinal fungi.

Extraction, structural elucidation and immunostimulating properties of water-soluble polysaccharides from wheat bran

A water-soluble polysaccharide was extracted from wheat bran (WBP) and investigate their structural characteristics and immunostimulatory activities. The chemical composition of WBP and purified fraction (WBP-F) mainly consists of neutral sugars (91.2 ± 1.2 and 98.7 ± 1.2%), proteins (8.6 ± 0.3 and 0.2 ± 0.1%) and uronic acids (0.7 ± 0.1 and 0.6 ± 0.1%). The molecular weight (M_w ) of WBP and WBP-F was calculated as 911.7 and 510.2 × 10³  g/mol, respectively. The WBP-F stimulates the RAW264.7 cells through the production of nitric oxide and various cytokines. The treatment of WBP-F facilitated the phosphorylation of P38, JNK, ERK, and NF-ƘB in RAW264.7 cells suggesting that they might stimulate RAW264.7 cells through the activation of NF-ƙB and MAPKs pathways. Furthermore, the structural details of WBP-F were studied by GC-MS and NMR spectrum, which confirms that the main backbone consists of 4-α-D-linked glucopyranosyl residues with branching points at C-6. PRACTICAL APPLICATIONS: Wheat bran is a potential source of health-promoting compounds. It has been reported that polysaccharides of wheat bran containing numerous beneficial activities. In this study, the wheat bran polysaccharide was extracted, fractionated and investigated their immunostimulatory activities. The results found in this study revealed that the purified polysaccharide from wheat bran potentially enhanced the RAW264.7 cells activation. Hence, these polysaccharides could be utilized as a potent immunity-enhancing agent in food and pharmaceutical industries.

Beta-glucan's varying structure characteristics modulate survival and immune-related genes expression from Vibrio harveyi-infected Artemia franciscana in gnotobiotic conditions

β-Glucans have long been used as an immunostimulant in aquaculture. However, the relationship of its structure to its immunomodulatory properties are poorly understood. In this study, the particle size and chemical structure of β-glucans extracted from wild-type strain of baker's yeast (Saccharomyces cerevisiae) and its null-mutant yeasts Gas1 were characterised. Using Sigma β-glucan as a reference, the immunomodulatory properties of these polysaccharides in the germ-free Artemia franciscana model system in the presence of Vibrio harveyi bacterial challenge were investigated. The survival of the A. franciscana nauplii, upon challenge with V. harveyi, was significantly higher in all three glucan-treated groups compared to the control. The glucan Gas1 with a lower degree of branching and shorter side chain length had the most prominent V. harveyi-protective effects. The particle size did not affect the nauplii survival when challenged with V. harveyi. Results also showed that the salutary effect of the tested glucans was associated with the upregulation of innate immune genes such as lipopolysaccharide and β-1,3-glucan-binding protein (lgbp), high mobility group box protein (hmgb), and prophenoloxidase (proPO). Interestingly, the up-regulation of superoxidase dismutase (sod) and glutathione-s-transferase (gst) was only observed in Gas1 treated group, indicating that Gas1 could function to induce higher reactive oxygen species and stronger immunomodulatory function in A. franciscana, and therefore higher survival rate. The expression of heat shock protein 70 (hsp70), peroxinectin (pxn), and down syndrome cell adhesion molecule (dscam) remain unaltered in response to glucan treatment. Taken together, this study provides insights into the structure-function relationship of β-glucan and the results confirmed that β-glucan can be an effective immunostimulant in aquaculture, especially the Gas1 glucan.

An innovative approach of priming lignocellulosics with lytic polysaccharide mono-oxygenases prior to saccharification with glycosyl hydrolases can economize second generation ethanol process

Two Lytic polysaccharide Mono-Oxygenases (LPMOs), non-modular (PMO_08942) and modular (PMO_07920), from thermotolerant fungus Aspergillus terreus 9DR cloned and expressed in Pichia pastoris X33 and purified to homogeneity using ion-exchange chromatography were found to be of ~29 and ~40 kDa, respectively. Both LPMOs were optimally active at 50 °C; PMO_08942 was active under acidic condition (pH 5.0) and PMO_07920 at pH 7.0. Modular LPMO (PMO_07920) tethered to CBM-1 was found to be versatile as it showed appreciable activity on complex polysaccharide (both cellulose and xylans) as compared to non-modular (PMO_08942). The t_1/2 of PMO_08942 (~192 h, pH 5.0) and PMO_0792 (~192 h, pH 7.0) at 50 °C, suggests highly stable nature of these LPMOs. Fluorescently tagged modular AA9 was studied microscopically to understand interaction with pretreated biomass. Priming of biomass for up to 6 h with LPMOs prior to initiating hydrolysis with core cellulase enzyme resulted in significantly higher saccharification.

Purification, Preliminary Structural Characterization, and In Vitro Inhibitory Effect on Digestive Enzymes by β-Glucan from Qingke (Tibetan Hulless Barley)

Background and Objective. Qingke (Tibetan hulless barley, Hordeum vulgare L.) contains a high content of β-glucan among all the cereal varieties. Although β-glucan has multiple physiological functions, the physiological function of qingke β-glucan was few studied. In this study, the β-glucan was isolated, purified, determined the structural characterization, and measured the inhibitory activity to enzymes correlating blood sugar and lipid. Methods. β-Glucan was isolated from enzymatic aqueous extract of qingke by using deproteinization, decolorization, DEAE-52 column chromatography, and sepharose CL-4B agarose gel column chromatography. The structure of the β-glucan was determined using FT-IR and 13C-NMR spectra analysis, and molecular mass by use of HPSEC-dRI-LS. The kinematic viscosity was measured. The inhibitory effects of this β-glucan on four enzymes were investigated. Results. This β-glucan had a uniform molecular weight of 201,000 Da with β-(1⟶4) as the main chain and β-(1⟶3) as a side chain. The β-glucan presented a relatively strong inhibitory activity on α-glucosidase, moderate inhibition on invertase, and a weak inhibition on α-amylase, whereas it did not inhibit lipase. Conclusion. The study indicates that the enzymatic β-glucan from qingke has the potential as natural auxiliary hypoglycemic additives in functional medicine or foods.

Bile acid-retention by native and modified oat and barley β-glucan

Foods rich in cereal β-glucan are efficient dietary tools to help reduce serum cholesterol levels and hence the risk of cardiovascular diseases. However, β-glucan undergoes various reactions during food processing, which alter its viscous properties and interactions with components of the gastrointestinal tract. It has been proposed in the literature that oxidation and partial hydrolysis increase β-glucan's bile acid-binding activity, and therefore its effectiveness in lowering cholesterol. Here, the passage kinetics of a bile salt mix across a dialysis membrane was studied with or without oat and barley β-glucan extracts, native or modified (partial hydrolysis and oxidations by sodium periodate or TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)). Bile acid-retention turned out to be purely a function of viscosity, with the most viscous native extracts exhibiting the strongest retardation of bile acid permeation. Opposite of what was suggested in the literature, oxidation and molecular weight reduction do not seem to increase the bile acid-binding capability of β-glucan.

Purification, structural characterization, and immunomodulatory activity of the polysaccharides from Ganoderma lucidum

A preliminary relationship was illustrated between the structural characteristics and corresponding immunomodulatory activities of G. lucidum polysaccharides. Two polysaccharides (GLP-1 and GLP-2) were purified from Ganoderma lucidum extracts by gradient ethanol precipitation and a Q-Sepharose Fast Flow (QFF) strong anion-exchange column. The monosaccharide composition, high-performance gel permeation chromatography-multi-angle laser light scattering-refractive index (HPGPC-MALLS-RI), Fourier-transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM), methylation analysis, and nuclear magnetic resonance (NMR) were used to characterize these polysaccharides. The GLP-1 polysaccharide was elucidated as d-galactoglucan with a flexible random linear conformation that mainly composed of →6)-β-d-Glcp-(1→, →6)-α-d-Galp-(1→, and →3)-β-d-Glcp-(1→ residues. GLP-2 was found to be a relatively homogeneous β-d-glucan that possessing →6)-β-d-Glcp-(1→ and →3)-β-d-Glcp-(1→ residues packaged into a spherical conformation. Immunomodulatory activities in vivo demonstrated that GLP-1 produced better protection of the spleen and thymus and was more effective for promoting hematopoiesis and improving IgA levels in serum. Our results suggest that the immunomodulatory activities of G. lucidum polysaccharides are highly corresponded to their structural characteristics such as carbohydrate composition, molecular weight and advanced conformation. This study provides a preliminary basis for studying the relationship between polysaccharide structure characterization and pharmacological activities.

Distribution of cell wall hemicelluloses in the wheat grain endosperm: a 3D perspective

Uneven distribution of AX and BG in lateral and longitudinal dimensions of a wheat grain was observed by three-dimensional MS imaging, presumably related to specific physicochemical properties of cell walls. Arabinoxylans (AX) and β-glucans (BG) are the main hemicelluloses that comprise the primary walls of starchy endosperm. These components are not evenly distributed in the endosperm, and the impact of their distribution on cell wall properties is not yet fully understood. Combined with on-tissue enzymatic degradation of the cell walls, mass spectrometry imaging (MSI) was used to monitor the molecular structure of AX and BG in thirty consecutive cross-sections of a mature wheat grain. A 3D image was built from the planar images, showing the distribution of these polymers at the full-grain level, both in lateral and longitudinal dimensions. BGs were more abundant at the vicinity of the germ and in the central cells of the endosperm, while AX, and especially highly substituted AX, were more abundant close to the brush and in the cells surrounding the crease (i.e., the transfer cells). Compared with the previously reported protocol, significant improvements were made in the tissue preparation to better preserve the shape of the fragile sections. This allowed to us achieve a good-quality 3D reconstruction from the consecutive 2D images. By providing a continuous view of the molecular distribution of the cell wall components across and along the grain, the three-dimensional images obtained by MSI may help understand the structure-function relationships of cell walls. The method should be readily extendable to other parietal polymers by selecting the appropriate enzymes.

Structural characterization and rheological properties of β-D-glucan from hull-less barley (Hordeum vulgare L. var. nudum Hook. f.)

A high purity of β-D-glucan (80.8%) from hull-less barley (Hordeum vulgare L. var. nudum Hook. f.) (HBBG) was isolated by alkali extraction and multi-precipitation with ethanol. The molecular weight (Mw) of HBBG was determined as 571.4 kDa with a broad distribution (Mw/Mn = 1.6) by using HPSEC. According to methylation and GC-MS analysis, HBBG was identified to be composed of (1 → 4)- and (1 → 3)-glucopyranosyl (Glcp) residues with a ratio of (3.19 ± 0.01). The MALDI-TOF MS and NMR spectroscopy were further conducted to analyze the enzyme hydrolysate released by lichenase digestion on HBBG. The results suggested that HBBG possessed a typical chemical structure of cereal β-D-glucans, namely linear homopolysaccharides formed by β-D-Glcp units via (1 → 4)-linkages and occasionally single (1 → 3)-linkage. The trisaccharide and tetrasaccharide of HBBG accounted for 66.6% of total cellulosyl units, accompanying with a ratio of cellotriosyl to cellotetraosyl units = 1.0, which were significant different from those reported for the other cereal β-glucans. Rheological property analysis revealed that HBBG showed a shear-thinning behavior and thermal resilience during heating-cooling process.

Changes of Chemical Composition and Hemicelluloses Structure in Differently Aged Bamboo ( Neosinocalamus affinis) Culms

To study the differences in chemical composition analysis and spatial distribution of young Neosinocalamus affinis bamboo, we used the methods of standard of National Renewable Energy Laboratory and confocal Raman microscopy, respectively. It was found that the acid-soluble lignin and acid-insoluble lignin content showed an inverse relationship with the increasing bamboo age. Raman analysis revealed that Raman signal intensity of lignin in both the secondary cell wall and the compound middle lamella regions showed a similar increase trend with growth of bamboo. In addition, eight hemicellulosic fractions were obtained by successively treating holocellulose of the 2-, 4-, 8-, and 12-month-old Neosinocalamus affinis bamboo culms with DMSO and alkaline solution. The ratio of arabinose to xylose of hemicelluloses was increased with the growth of bamboo. FT-IR and NMR analyses revealed that DMSO-soluble hemicelluloses of young bamboo culms are mainly composed of highly substituted xylans and β-d-glucans.

Development of a complete set of wheat-barley group-7 Robertsonian translocation chromosomes conferring an increased content of β-glucan

A complete set of six compensating Robertsonian translocation chromosomes involving barley chromosome 7H and three chromosomes of hexaploid wheat was produced. Grain β-glucan content increased in lines containing 7HL. Many valuable genes for agronomic performance, disease resistance and increased yield have been transferred from relative species to wheat (Triticum aestivum L.) through whole-arm Robertsonian translocations (RobT). Although of a great value, the sets of available translocations from barley (Hordeum vulgare L.) are limited. Here, we present the production of a complete set of six compensating RobT chromosomes involving barley chromosome 7H and three group-7 chromosomes of wheat. The barley group-7 long-arm RobTs had a higher grain β-glucan content compared to the wheat control. The β-glucan levels varied depending on the temperature and were higher under hot conditions. Implicated in this increase, the barley cellulose synthase-like F6 gene (CslF6) responsible for β-glucan synthesis was physically mapped near the centromere in the long arm of barley chromosome 7H. Likewise, wheat CslF6 homoeologs were mapped near the centromere in the long arms of all group-7 wheat chromosomes. With the set of novel wheat-barley translocations, we demonstrate a valuable increase of β-glucan, along with a resource of genetic stocks that are likely to carry many other important genes from barley into wheat.

Microbial Competition of Rhodotorula mucilaginosa UANL-001L and E. coli increase biosynthesis of Non-Toxic Exopolysaccharide with Applications as a Wide-Spectrum Antimicrobial

Bacterial species are able to colonize and establish communities in biotic and abiotic surfaces. Moreover, within the past five decades, incidence of bacterial strains resistant to currently used antibiotics has increased dramatically. This has led to diverse health issues and economical losses for different industries. Therefore, there is a latent need to develop new and more efficient antimicrobials. This work reports an increased production of an exopolysaccharide in a native yeast strain isolated from the Mexican Northeast, Rhodotorula mucilaginosa UANL-001L, when co-cultured with E. coli. The exopolysaccharide produced is chemically and physically characterized and its applications as an antimicrobial and antibiofilm are explored. The exopolysaccharide is capable of inhibiting planktonic growth and biofilm formation in Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. Additionally, the exopolysaccharide studied here does not exhibit cytotoxic effects when assessed both, in vitro against an H9c2 mammalian cell line, and in vivo in a murine toxicity model. Taken together, the properties of this exopolysaccharide indicate that it has potential applications to inhibit bacterial colonization in medical and industrial settlings.

Addition of Aegilops U and M Chromosomes Affects Protein and Dietary Fiber Content of Wholemeal Wheat Flour

Cereal grain fiber is an important health-promoting component in the human diet. One option to improve dietary fiber content and composition in wheat is to introduce genes from its wild relatives Aegilops biuncialis and Aegilops geniculata. This study showed that the addition of chromosomes 2Ug, 4Ug, 5Ug, 7Ug, 2Mg, 5Mg, and 7Mg of Ae. geniculata and 3Ub, 2Mb, 3Mb, and 7Mb of Ae. biuncialis into bread wheat increased the seed protein content. Chromosomes 1Ug and 1Mg increased the proportion of polymeric glutenin proteins, while the addition of chromosomes 1Ub and 6Ub led to its decrease. Both Aegilops species had higher proportions of β-glucan compared to arabinoxylan (AX) than wheat lines, and elevated β-glucan content was also observed in wheat chromosome addition lines 5U, 7U, and 7M. The AX content in wheat was increased by the addition of chromosomes 5Ug, 7Ug, and 1Ub while water-soluble AX was increased by the addition of chromosomes 5U, 5M, and 7M, and to a lesser extent by chromosomes 3, 4, 6Ug, and 2Mb. Chromosomes 5Ug and 7Mb also affected the structure of wheat AX, as shown by the pattern of oligosaccharides released by digestion with endoxylanase. These results will help to map genomic regions responsible for edible fiber content in Aegilops and will contribute to the efficient transfer of wild alleles in introgression breeding programs to obtain wheat varieties with improved health benefits. Key Message: Addition of Aegilops U- and M-genome chromosomes 5 and 7 improves seed protein and fiber content and composition in wheat.

Clinical and Physiological Perspectives of β-Glucans: The Past, Present, and Future

β-Glucans are a group of biologically-active fibers or polysaccharides from natural sources with proven medical significance. β-Glucans are known to have antitumor, anti-inflammatory, anti-obesity, anti-allergic, anti-osteoporotic, and immunomodulating activities. β-Glucans are natural bioactive compounds and can be taken orally, as a food supplement, or as part of a daily diet, and are considered safe to use. The medical significance and efficiency of β-glucans are confirmed in vitro, as well as using animal- and human-based clinical studies. However, systematic study on the clinical and physiological significance of β-glucans is scarce. In this review, we not only discuss the clinical and physiological importance of β-glucans, we also compare their biological activities through the existing in vitro and animal-based in vivo studies. This review provides extensive data on the clinical study of β-glucans.