Characterisation of partially hydrolysed galactomannan from Caesalpinia pulcherrima seeds as a potential dietary fibre

Dielectric Response of Crosslinked Adenanthera pavonina L. Galactomannan in pH-Controlled Medium

This research investigates the production of galactomannan from Adenanthera pavonina L. in its crude form and its subsequent crosslinking with glutaraldehyde under various pH conditions. The study involved the creation of films and sponges from these materials, followed by a comprehensive analysis of their structural, thermal, swelling, and electrical properties. Galactomannan was crosslinked with a fixed concentration of 0.2 mol/L of glutaraldehyde, with pH levels ranging from 3 to 7. These films and sponges were prepared through a slow solvent evaporation process. The research encompassed multiple analytical techniques, including Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, swelling profile assessments, and impedance spectroscopy. The findings from structural analysis indicated that variations in pH did not alter the amorphous nature of the samples but did influence the interactions between galactomannan molecules and restricted the mobility of polymeric chains, which resulted in different dielectric responses. Crosslinked samples exhibited reduced water solubility compared to unprocessed galactomannan. Crosslinking also decreases the ability of the material to polarize and align in response to the electric field, which justifies why crosslinked samples present a lower dielectric constant than the crude sample.

Determination of physicochemical, functional,and morphological properties of Prosopis farcta (Çeti̇) seed galactomannan as a new hydrocolloid source: Comparison with locust bean gum

The present study investigated the properties of galactomannan, a water-soluble polysaccharide extracted from the Prosopis farcta (Çeti) plant. These properties encompassed its functional characteristics, chemical composition, rheological behavior, and morphological structure. The results were systematically compared with those of the commercially utilized locust bean gum (LBG). Following ethanol precipitation, the yield of Prosopis farcta galactomannan (PFG) was determined to be 22.4 ± 0.5 %. The mannose-to-galactose (M: G) ratios of PFG and LBG were calculated as 1.7:1 and 3.3:1, respectively. The solubility of PFG exhibited a temperature-dependent increase akin to that of LBG. Notably, PFG demonstrated superior emulsion capacity and stability even at low concentrations. Additionally, the X-ray diffraction (XRD) analysis revealed asymmetric broad peaks around the 2θ = 20° diffraction angle, signifying the amorphous nature of PFG. Scanning electron microscopy (SEM) images, obtained after dissolving both PFG and LBG in deionized water and freeze-drying them, displayed a fibrous filament network structure in both samples.

Effects of galactomannans of varied structural features on the functional characteristics and in vitro digestibility of wheat starch

This study explores the effects of four natural galactomannans (GMs) with varying degrees of branching (fenugreek gum, guar gum, tara gum and locust bean gum) on the functional properties and in vitro digestibility of wheat starch (WS). Results from rapid viscosity analysis (RVA) and low-field nuclear magnetic resonance (LF-NMR) analysis revealed that GMs with lower branching degrees were correlated with higher paste viscosity, peak viscosity, and greater water-holding capacity in the WS-GM mixtures. Additionally, these lower branching GMs more effectively inhibited amylose leaching during starch gelatinization, leading to a softer gel texture and increased transparency of the mixtures. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis demonstrated that starch mixtures containing lower branching GMs exhibited reduced relative crystallinity and enthalpy values during aging. Furthermore, the incorporation of lower branching GMs resulted in decreased starch digestibility in vitro, thereby enhanced resistant starch content. These findings highlight the potential of selectively branched GMs to modulate the functional properties and nutritional profile of WS, providing a promising approach for the development of starch-based products with improved health benefits.

Understanding the dynamic evolution of hemicellulose during Pinus taeda L. growth

Pinus taeda L. is a fast-growing softwood with significant commercial value. Understanding structural changes in hemicellulose during growth is essential to understanding the biosynthesis processes occurring in the cell walls of this tree. In this study, alkaline extraction is applied to isolate hemicellulose from Pinus taeda L. stem segments of different ages (1, 2, 3, and 4 years old). The results show that the extracted hemicellulose is mainly comprised of O-acetylgalactoglucomannan (GGM) and 4-O-methylglucuronoarabinoxylan (GAX), with the molecular weights and ratios (i.e., GGM:GAX) of GGM and GAX increasing alongside Pinus taeda L. age. Mature Pinus taeda L. hemicellulose is mainly composed of GGM, and the ratio of (mannose:glucose) in the GGM main chain gradually increases from 2.45 to 3.60 with growth, while the galactose substitution of GGM decreases gradually from 21.36% to 14.65%. The acetylation of GGM gradually increases from 0.33 to 0.45 with the acetyl groups mainly substituting into the O-3 position in the mannan. Furthermore, the contents of arabinose and glucuronic acid in GAX gradually decrease with growth. This study can provide useful information to the research in genetic breeding and high-value utilization of Pinus taeda L.

Characterization of hemicellulose in Cunninghamia lanceolata stem during xylogenesis

In this study, hemicellulose was isolated from the apical, middle and basal segments of C. lanceolata stem to investigate the dynamic change of its structure during xylogenesis. Results showed that the C. lanceolata hemicellulose is mainly consisted of O-acetylgalactoglucomannan (GGM) which backbone is alternately linked by β-d-mannopyranosyl (Manp) and β-d-glucopyranosyl (Glcp) via (1 → 4)-glycosidic bond, while the side chains are α-d-galactopyranosyl (Galp) and acetyl. In addition, 4-O-methylglucuronoarabinoxylan (GAX) is another dominant structure of C. lanceolata hemicellulose which contains a linear backbone of (1 → 4)-β-d-xylopyranosyl (Xylp) and side chains of 4-O-Me-α-d-glucuronic acid (MeGlcpA) and α-L-arabinofuranose (Araf). The thickness of the cell wall, the ratio of GGM/GAX and the molecular weight of hemicellulose were increased as the extension of growth time. The degree of glycosyl substitutions of xylan and mannan was decreased from 10.34 % (apical) to 8.38 % (basal) and from 15.63 % (apical) to 10.49 % (basal), respectively. However, the total degree of acetylation was enhanced from 0.28 (apical) to 0.37 (basal). Transcriptome analysis showed that genes (CSLA9, IRX9H1, IRX10L, IRX15L, GMGT1, TBL19, TBL25, GUX2, GUX3, GXM1, F8H1 and F8H2) related to hemicellulose biosynthesis are mainly expressed in mature part. This study is of great significance for genetic breeding and high-value utilization of C. lanceolata.

Brewer's Spent Grain Enhanced the Recovery of Potential Probiotic Strains in Fermented Milk After Exposure to In Vitro-Simulated Gastrointestinal Conditions

Brewer's spent grain (BSG) is a beer industry by-product with interesting functional properties by its high fiber content and bioactive compounds, which may be possibly employed as a prebiotic ingredient. The fermentability of BSG by ten probiotics and two starter cultures was evaluated, and the co-culture of Lacticaseibacillus paracasei subsp. paracasei F-19® (probiotic) and Streptococcus thermophilus TH-4® (starter) was selected to produce a potentially probiotic fermented milk (FM). Four formulations of FM were studied: FM1 (control), FM2 (probiotic - /BSG +), FM3 (probiotic + /BSG -), and FM4 (probiotic + /BSG +). The viability of the microorganisms in the FM was monitored throughout 28 days of storage. The resistance of the microorganisms in the FM to in vitro-simulated gastrointestinal tract (GIT) conditions was also evaluated. Even though the BSG did not influence the fermentation kinetics or increase the populations of both microorganisms in the FM, a significant improvement on the survival of TH-4® against in vitro-simulated GIT stress was observed in the formulations containing BSG alone or in combination with F-19®. All formulations showed potential as probiotic FM, since total probiotic populations were kept above 10¹⁰ CFU in a daily portion of 200 mL, and a minimum of 10¹⁰ and 10⁸ CFU equivalent of, respectively, TH-4® and F-19® was recovered after the GIT stress. Therefore, TH-4® has potential as a probiotic strain in addition to its starter feature, while BSG may be employed as a possible prebiotic ingredient in a synbiotic approach. Nonetheless, further studies to evaluate possible health benefits are needed.

Changes in structure and physicochemical properties of Sophora japonica f. pendula galactomannan in late growth stage

Galactomannan (GM) has been widely applied in food and other fields due to its appealing physicochemical properties. In this work, considering the changes in structural and physicochemical properties of Sophora japonica f. pendula (SJ-GM) with very high mannose to galactose (M/G) ratio in the late deposition stage, extensive exploration is conducted. The core of structural change is the change of M/G ratio (4.94-5.68), which is caused by the loss of galactose side residues modulated by α-d-galactosidase during seed maturation. Afterwards, the more compact conformation, the higher molecular weight, the increased hydrophobicity, and the greater solution viscosity of SJ-GM can be caused. Notably, the gel strength of SJ-GM with the highest M/G surpasses other GMs, including fenugreek gum (M/G = 1.20), guar gum (M/G = 1.80), Gleditsia microphylla gum (M/G = 2.77), and LBG (M/G = 4.00). Finally, SJ-GM is proven to be an attractive alternative to other GMs.

Effect of Loblolly Pine (Pinus taeda L.) Hemicellulose Structure on the Properties of Hemicellulose-Polyvinyl Alcohol Composite Film

Hemicellulose is the second most abundant natural polysaccharide and a promising feedstock for biomaterial synthesis. In the present study, the hemicellulose of loblolly pine was obtained by the alkali extraction-graded ethanol precipitation technique, and the hemicellulose-polyvinyl alcohol (hemicellulose-PVA) composite film was prepared by film casting from water. Results showed that hemicellulose with a low degree of substitution is prone to self-aggregation during film formation, while hemicellulose with high branching has better compatibility with PVA and is easier to form a homogeneous composite film. In addition, the higher molecular weight of hemicellulose facilitates the preparation of hemicellulose-PVA composite film with better mechanical properties. More residual lignin in hemicellulose results in the better UV shielding ability of the composite film. This study provides essential support for the efficient and rational utilization of hemicellulose.

Structure characterization and in vitro hypoglycemic effect of partially degraded alginate

Alginate is a low-cost polysaccharide found abundantly in seaweeds which consists of mannuronate and guluronate, and it is considered a sustainable gum source for dietary fiber. To solve the high viscosity-related problems while retaining its physiological properties, four partially degraded alginate products (PDA1-4) with molecular weight of 1.05-0.40 × 10⁵ g mol^-1 and intrinsic viscosity of 170.9-38.9 mL g^-1 were enzymatically prepared and characterized. ¹H Nuclear magnetic resonance analysis showed the used alginate lyase had a preference to degrade guluronate-blocks. PDA1 and PDA2 presented random coil conformation, whereas PDA3 and PDA4 displayed compact spherical-coil conformation over random coil conformation in solution. In vitro assays suggested a glucose-adsorption capacity order of PDA1 < PDA2 < alginate < PDA3 < PDA4 and a glucose-diffusion retardation capacity order of PDA3 < PDA1 ≤ alginate < PDA2 < PDA4, indicating that partially degraded alginate reinforced the hypoglycemic effect, especially mannuronate-rich PDA4. Overall, the study may have important implications for development of PDA as dietary fiber with potential hypoglycemic activity.

Galactomannan of Delonix regia seeds reduces nociception and morphological damage in the rat model of osteoarthritis induced by sodium monoiodoacetate

This study investigated the effects of the protein-free galactomannan obtained from Delonix regia seeds (GM-DR) in an experimental osteoarthritis (OA) model. GM-DR was obtained from water-homogenized endosperms by collection of the supernatant and precipitation with ethanol. The remaining proteins in the galactomannan were removed by alkaline hydrolysis. Weight average molar mass (Mw) of the galactomannan was estimated in 5.8 × 105 g mol-1, presenting mannose:galactose ratio of 2.39:1. Rats received sodium monoiodoacetate (OA groups, 1 mg/25 μL) or saline (sham group) in the right tibio-tarsal joint. GM-DR (30-300 μg) was administered by intra-articular route at days 14 and 21 after OA induction. Hypernociception was evaluated daily by the measurement of the mechanical threshold required to cause joint flexion and paw withdrawal reflex. The 56-day animal groups were euthanized for joint histopahological analysis using the OARSI score system. Lower doses of GM-DR (30 and 100 μg) promoted antinociception from day 15 until the endpoint at day 56. Joint damage was reduced by GM-DR administration (100 μg) in OA-subjected animals, compared to the vehicle-treated OA group (5.9 ± 1.8 vs 19.0 ± 1.8, respectively, p < 0.05). Conclusion: Both antinociception and damage reduction suggest that Delonix regia galactomannan is a promising approach for osteoarthritis therapy.

Poly(N-isopropylacrylamide)/galactomannan from Delonix regia seed thermal responsive graft copolymer via Schiff base reaction

Aminated poly(N-isopropylacrylamide) (PNIPAm-NH₂) was grafted onto oxidized galactomannan polysaccharide extracted from Delonix regia (OXGM) via Schiff base reaction by a simple, rapid synthetic route, deprived of the use of organic solvents. Grafting was confirmed by FTIR and ¹H NMR and the self-organizing ability of the obtained nanoparticle copolymers was investigated by dynamic light scattering (DLS). The minimum concentration required for self-organization (CAC) at 25 °C was higher than at 50 °C. Lower critical solution temperature (LCST) was in the range 34-40 °C, depending on both inserted PNIPAm-NH₂ molar mass and on the presence of reduced imine bond. Synthesized copolymers are promising candidates for drug delivery as they show good cell viability, particle size around 250 nm and transition temperature closer to that of human body. Reaction success points out to the possibility of use free aldehyde groups of oxidized polysaccharide, not used in the copolymerization, to form a pro-drug with substances that possess NH₂ groups in their structure, such as doxorubicin.

Effect of high voltage atmospheric cold plasma on extraction of fenugreek galactomannan and its physicochemical properties

Fenugreek is a good source of galactomannan, however, conventional methods for its extraction are generally time-consuming and have relatively low recovery rates. In this study, we applied high voltage atmospheric cold plasma (HVACP) as a pretreatment and investigated its effects on galactomannan extraction from dry fenugreek seeds and soaked seeds in NaCl solution, as well as its physicochemical properties. Results showed that HVACP treatment with air at 80 kV for 30 min caused apparent structural disruption on fenugreek seed surface and decreased the pH of extracting solution, resulting in increased galactomannan extraction yields, by 122% from soaked seeds and 67% from dry seeds. Galactomannan treated with HVACP had higher water-binding capacity, swelling index and viscosity, as well as lower melting enthalpy. HVACP treatment also altered the surface morphology of galactomannan due to plasma etching, but no significant changes in its molecular and crystalline structures were observed. The findings of this study prove that HVACP can be a green approach, in terms of reduced chemical use, to effectively enhance the extraction efficiency of fenugreek galactomannan and modify its functional properties, hence facilitate more diverse applications in both food and polymer industries.

Chemical characterization, antioxidant properties and anticancer activity of exopolysaccharides from Floccularia luteovirens

Two polysaccharides, ALF1 and ALF2 were obtained from the fermentation liquid of Floccularia luteovirens. These fractions had good performance in scavenging radicals and ALF1 exhibited obvious antioxidant activities. Further, linkage analysis and NMR were used to characterize the structures of ALF1. Linkage and NMR data comprehensively showed that ALF1 mainly contained six kinds of linkage type units as →4)-β-D-Manp→, 1,3-α-Fucp→, α-L-Araf-C1→, →6)-β-D-Galp-C1→, →4)-α-D-GlcAp-(1→ and →3)-β-D-Glcp(1→. In addition, ALF1 had good bioactivities such as anticancer and antioxidant activities. ALF1 was proven to be able to inhibit tumor cells without affecting the normal cells. Besides, ALF1 improved the activities of SOD, GSH-Px and CAT, and decreased the production of MDA which result in protecting PC12 cells against H₂O₂-induced oxidative stress. ALF1 decreased ROS production, and stabilize mitochondrial membrane potential. The findings indicated that the fermentation liquid of Floccularia luteovirens could be used as a potential natural source of antioxidant.

The anticonvulsant effect of a polysaccharide-rich extract from Genipa americana leaves is mediated by GABA receptor

BACKGROUND

This study aimed to chemically characterize a polysaccharide-rich extract (PRE) obtained from Genipa americana leaves and evaluate its neuroprotective effect in the brain morphology and oxidative markers using mice behavioral models.

METHODS

Dry powder (5 g) of G. americana leaves were submitted to depigmentation in methanol. PRE was obtained by extraction in NaOH and precipitation with absolute ethanol and characterized by infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹H and ¹³C NMR). Swiss mice (25-35 g) received saline (0.9% NaCl) or PRE (1-27 mg/kg) by intraperitoneal (i.p.) route, 30 min before evaluation in behavioral models (open field, elevated plus maze, sleeping time, tail suspension, forced swimming, seizures induced by pentylenetetrazole-PTZ). Animal's brain were dissected and analyzed for histological alterations and oxidative stress.

RESULTS

FTIR spectrum showed bands around 3417 cm^-1 and 2928 cm^-1, relative to the vibrational stretching of OH and CH, respectively. ¹H NMR spectrum revealed signals at δ 3.85 (methoxyl groups) and δ 2.4 (acetyl) ppm. ¹³C NMR spectrum revealed signals at δ 108.0 and δ 61.5 ppm, corresponding to C1 and C5 of α-L-arabinofuranosyl residues. PRE presented central inhibitory effect, increasing the latency for PTZ-induced seizures by 63% (9 mg/kg) and 55% (27 mg/kg), and the latency to death by 73% (9 mg/kg) and 72% (27 mg/kg). Both effects were reversed by the association with flumazenil.

CONCLUSIONS

PRE, containing a heteropolysaccharide, presents antioxidant and anticonvulsant effect in the model of PTZ-induced seizures via gamma-aminobutyric acid (GABA), decreasing the number of hippocampal black neurons.

Aggregation and rheological behavior of soluble dietary fibers from wheat bran

The present study assesses the aggregation behavior of wheat bran arabinoxylan-rich soluble dietary fiber (SDF) fractions with diverse molecular weight and substitution in order to provide useful information to prevent the formation of a block network. In the present work, dynamic and static light scattering, diffusing wave spectroscopy, small amplitude dynamic rheology, atomic force microscopy, and the water-holding and swelling capacities were evaluated to assess the SDF aggregation behavior induced by intrinsic and extrinsic factors. Furthermore, the rheological behavior was explained by the physically cross-linked or interpenetrating hydrocolloid network established during SDF self-aggregation, dependent on its molecular structure. The results indicated that the SDF fractions exhibiting a high molecular weight and a lower substitution degree and di-substituted ratio led to more significant aggregation due to the formation of disordered tangles coupled with a more solid-like behavior. The obtained information will prove useful for the development of more stable and compatible SDF fractions.

Supplementation with fruit and okara soybean by-products and amaranth flour increases the folate production by starter and probiotic cultures

The ability of two starter cultures (Streptococcus (S.) thermophilus ST-M6 and St. thermophilus TA-40) and eleven probiotic cultures (St. thermophilus TH-4, Lactobacillus (Lb.) acidophilus LA-5, Lb. fermentum PCC, Lb. reuteri RC-14, Lb. paracasei subsp. paracasei, Lb. casei 431, Lb. paracasei subsp. paracasei F19, Lb. rhamnosus GR-1, and Lb. rhamnosus LGG, Bifidobacterium (B.) animalis subsp. lactis BB-12, B. longum subsp. longum BB-46, and B. longum subsp. infantis BB-02) to produce folate in a modified MRS broth (mMRS) supplemented with different fruit (passion fruit, acerola, orange, and mango) and okara soybean by-products and amaranth flour was investigated. Initially, the folate content of each vegetable substrate was determined: passion fruit by-product showed the lowest folate content (8±2ng/mL) and okara the highest (457±22ng/mL). When the orange by-product and amaranth flour were added to mMRS, all strains were able to increase folate production after 24h of fermentation. B. longum subsp infantis BB-02 produced the highest concentrations (1223±116ng/mL) in amaranth flour. Okara was the substrate that had the lowest impact on the folate production by all strains evaluated. Lb. acidophilus LA-5 (297±36ng/mL) and B. animalis subsp. lactis BB-12 (237±23ng/mL) were also able to produce folate after growth in mMRS containing acerola and orange by-products, respectively. The results of this study demonstrate that folate production is not only strain-dependent but also influenced by the addition of different substrates in the growth media.

Structure Characterization and Immunomodulating Effects of Polysaccharides Isolated from Dendrobium officinale

A crude polysaccharide fraction (cDOP) has been determined to be the characteristic marker of Dendrobium officinale, an expensive tea material in Asia, but its chemistry and bioactivity have not been studied. In work reported here, cDOP was destarched (DOP, 90% yield) and separated into two subfraction polysaccharides, DOPa and DOPb, which were characterized by monosaccharide composition and methylation analyses and spectral analyses (FT-IR and (1)H and (13)C NMR). Both are composed of mannose and glucose at similar ratios and have a similar structure with a backbone of 1,4-linked β-D-mannopyranosyl and β-D-glucopyranosyl residues. Significant differences were observed only in their molecular weights. Bioassay using mouse macrophage cell line RAW264.7 indicated that DOP and its two subfractions enhance cell proliferation, TNF-α secretion, and phagocytosis in a dose-dependent manner. They also induced the proliferation of lymphocytes alone and with mitogens. DOPa and DOPb are thus proven to be major, active polysaccharide markers of D. officinale.