Physicochemical characterization of galactomannans extracted from seeds of Gleditsia sinensis Lam and fenugreek. Comparison with commercial guar gum

Valorization of Cassia tora Seeds: Extraction and Biofunctional Characterization of Cassia tora Seed Gum

Cassia tora, an annual shrub, is a promising but underexplored source of galactomannan, comparable to widely used sources, such as fenugreek, guar, and locust bean. Galactomannans are heteropolysaccharides composed of galactose and mannose, valued for their role as dietary fibers and texture modifiers in food applications. This study aimed to optimize Cassia tora gum's extraction process, characterize its physiochemical properties, and quantify its galactomannan content to assess its potential as a gelling agent. The extraction process was optimized by varying key parameters, including the water-to-seed powder ratio, boiling time, and mucilage-to-ethanol ratio, achieving a 96% recovery of gum, higher than the reported yield with high purity. Physiochemical analysis revealed that the extracted gum contained 84.12% carbohydrate with a galactose-to-mannose ratio of 1:5. Galactomannan content was determined to be 55% in raw Cassia seeds. Rheological studies demonstrated a minimum gelation concentration of 75%, highlighting the gum's potential as an efficient gelling agent. These findings underscore the feasibility of utilizing Cassia tora as a sustainable and cost-effective source of galactomannan for food and industrial applications, offering a valuable alternative to conventional sources.

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.

Green preparation of low-molecular-weight galactomannan from Gleditsia sinensis and mechanistic investigation on ameliorating nonalcoholic fatty liver disease

Galactomannan comes from a wide range of plant resources and has some biological activities, but its bioavailability is limited due to its large molecular weight and complex structure. In this study, three degradation methods (H2O2, ultrasound, and β-mannanase) combined with ethanol fractional precipitation (25 %, 50 %, and 75 %) were used to degrade and separate Gleditsia sinensis galactomannans (GSG), and the physicochemical properties and biological activities of GSG after degradation were analyzed. Comprehensive comparison indicates that H2O2 exhibits had a better degradation effect. After 4 h of degradation using 4 % H2O2, the yield of GSG precipitated with 50 % ethanol was 37.06 % (the yield of undigested GSG is 1.80 %). Simultaneously, the molecular weight (reduced from 225.25 to 36.87 kDa) and viscosity were significantly reduced under this condition, while the solubility was increased. In addition, the low-molecular-weight GSG (LGSG) obtained by 4 % H2O2/50 % ethanol showed the strongest free radical scavenging activity in vitro. Furthermore, the results of in vivo antioxidant assays showed that LGSG inhibited Aflatoxin B1-induced developmental toxicity by regulating gene expression in the Keap1/Nrf2 pathway. LGSG also promoted Nrf2-mediated expression of the lipid metabolism genes ppar-α and cpt1, while suppressing expression of the fatty acid synthesis genes fas and scd-1. Therefore, the liver recovered from lipid peroxidation induced nonalcoholic fatty liver disease (NAFLD). The present study introduces a method for green and efficient preparation of LGSG, indicates its potential as a nutritional product.

A comprehensive review on guar gum and its modified biopolymers: Their potential applications in tissue engineering

Guar gum (GG), as a non-exudate gum, is extracted from the seed's embryos of Cyamopsis tetragonoloba (a member of Leguminosae family). Recently, this biopolymer has received extensive attention due to its low cost, notable properties, non-toxic biodegradation, ease of availability, and biocompatibility. However, disadvantages such as uncontrolled hydration rate and susceptibility to microbial attack have led many researchers to further modification of guar gum. Further modifications of guar gum heteropolysaccharide have been performed to improve properties and explore and expand its potential. The favorable biostability, improved solubility, and swelling, increased pH sensitivity, and good antibacterial and antioxidant properties indicate the significant advantages of the modified gum structures with different functional groups. In this review, the rapid growth in research on GG derivatives-based materials has been discovered. Besides, the production methods of GG and its derivatives have been discussed in tissue engineering and regenerative medical. Consequently, this review highlights the advances in the production of guar-based products to outline a promising future for this biopolymer by changing its properties and expanding its applications in potential targets.

Effects of Separation and Purification Methods on Antioxidation, Hypoglycemic and DNA Protection Activity of Fenugreek Polysaccharide

Six low molecular weight fenugreek polysaccharides (FP) were isolated and purified by ethanol stepwise precipitation (EFP-20, EFP-40, and EFP-60) and DEAE-52 cellulose column method (DFP-0, DFP-0.15, and DFP-0.3), respectively. The effects of different separation and purification techniques on the preliminary properties and biological activities of fenugreek polysaccharides were compared. The results showed that the DEAE-52 cellulose-eluted fractions had a higher total sugar content and displayed a looser structure. The molecular weights of all six fractions were in the range of 4-19 kDa, with significant changes in the ratio of galactose to mannose. All six fractions contained α-D-galactopyranose and β-D-mannopyranose structures. Activity tests showed that all six fractions possessed antioxidant, hypoglycemic and DNA-protective activities. Among them, the DFP-0 fraction showed the highest activity. Overall, different isolation and purification methods lead to changes in the properties and bioactivities of FP, which provides a theoretical basis for the development and application of FP in functional foods and drugs.

Recent updates on guar gum derivatives in colon specific drug delivery

Colon specific delivery of therapeutics have gained much attention of pharmaceutical researchers in the recent past. Colonic specific targeting of drugs is used not only for facilitating absorption of protein or peptide drugs, but also localization of therapeutic agents in colon to treat several colonic disorders. Among various biopolymers, guar gum (GG) exhibits pH dependent swelling, which allows colon specific release of drug. GG also shows microbial degradation in the colonic environment which makes it a suitable excipient for developing colon specific drug delivery systems. The uncontrolled swelling and hydration of GG can be controlled by structural modification or by grafting with another polymeric moiety. Several graft copolymerized guar gum derivatives are investigated for colon targeting of drugs. The efficacy of various guar gum derivatives are evaluated for colon specific delivery of drugs. The reviewed literature evidenced the potentiality of guar gum in localizing drugs in the colonic environment. This review focuses on the synthesis of several guar gum derivatives and their application in developing various colon specific drug delivery systems including matrix tablets, coated formulations, nano or microparticulate delivery systems and hydrogels.

Isolation, structural, biological activity and application of Gleditsia species seeds galactomannans

Gleditsia fruits have been known as a valuable traditional Chinese herb for tens of centuries. Previous studies showed that the galactomannans are considered as one of the major bioactive components in Gleditsia fruits seeds (GSGs). Here, we systematically review the major studies of GSGs in recent years to promote their better understanding. The extraction methods of GSGs mainly include hot water extraction, microwave-assisted extraction, ultrasonic extraction, acid extraction, and alkali extraction. The analysis revealed that GGSs exhibited in the form of semi-flexible coils, and its molecular weight ranged from 0.018 × 103 to 2.778 × 103 KDa. GSGs are composed of various monosaccharide constituents such as mannose, galactose, glucose, and arabinose. In terms of pharmacological effects, GSGs exhibit excellent activity in antioxidation, hypoglycemic, hypolipidemic, anti-inflammation. Moreover, GSGs have excellent bioavailability, biocompatibility, and biodegradability, which make them used in food additives, food packaging, pharmaceutical field, industry and agriculture. Of cause, the shortcomings of the current research and the potential development and future research are also highlighted. We believe our work provides comprehensive knowledge and underpinnings for further research and development of GSGs.

Fractionation and physicochemical characterization of dietary fiber of kenaf (Hibiscus cannabinus L.) seed

BACKGROUND

Kenaf seeds are underutilized kenaf plant by-products, containing essential nutrients including dietary fiber (DF), which can be potentially utilized as food ingredients. The present study aimed to evaluate the physicochemical characteristics of kenaf seed fiber fractions extracted from kenaf seed.

RESULTS

Defatted kenaf seed powder yielded four DF fractions: alkali-soluble hemicellulose (146.4 g kg-1 ), calcium-bound pectin (10.3 g kg-1 ) and acid-soluble pectin (25.4 g kg-1 ) made up the soluble fibre fraction, whereas cellulose (202.2 g kg-1 ) comprised the insoluble fraction. All fractions were evaluated for their physicochemical properties. The DF fractions contained glucose, mannose, xylose and arabinose, and a small amount of uronic acid (1.2-2.7 g kg-1 ). The isolated pectin fractions had a low degree of esterification (14-30%). All the isolated DF fractions had high average molecular weights ranging from 0.3 to 4.3 × 106 g mol-1 . X-ray diffractogram analysis revealed that the fractions consisted mainly of an amorphous structure with a relative crystallinity ranging from 31.6% to 44.1%. The Fourier-transform infrared spectroscopy spectrum of kenaf seed and its DF fractions showed typical absorption of polysaccharides, with the presence of hydroxyl, carboxyl, acetyl and methyl groups. Scanning electron microscopy analysis demonstrated that the raw material with the rigid structure resulted in soluble and insoluble DF fractions with more fragile and fibrous appearances, respectively. The soluble DF demonstrated greater flowability and compressibility than the insoluble fractions.

CONCLUSION

These findings provide novel information on the DF fractions of kenaf seeds, which could be used as a potential new DF for the food industry. © 2023 Society of Chemical Industry.

Study on structure and properties of galactomannan and enzyme changes during fenugreek seeds germination

Fenugreek (Trigonella foenum-graecum L) galactomannan play an important role in the food and pharmaceutical sectors due to its attractive physicochemical properties. In this study, the changes of structure, properties and biological activity of fenugreek galactomannan (FG) during germination are analyzed by the activity and mechanism of endogenous enzymes (α-D-galactosidase and β-D-mannanase). The enzymes generally increased during germination and synergistically altered the structure of GM by cutting down the main chains and removing partial side residues. The mannose to galactose ratio (M/G) increased from 1.11 to 1.59, which is accompanied by a drastic decrease in molecular weight from 3.606 × 106 to 0.832 × 106 g/mol, and the drop of viscosity from 0.27 to 0.06 Pa·sn. The degraded macromolecules are attributed to the increase in solubility (from 64.55 % to 88.62 %). In terms of antioxidation and antidiabetic ability, germinated fenugreek galactomannan has the ability to scavenge 67.17 % ABTS free radicals and inhibit 86.89 % α-glucosidase. This galactomannan with low molecular weight and excellent biological activity precisely satisfies the current demands of pharmaceutical reagents and food industry. Seeds germination holds promise as a means of industrial scale production of low molecular weight galactomannans.

Recent advances in plant-based polysaccharide ternary complexes for biodegradable packaging

Polysaccharide-based packaging has been directed toward the development of technologies for the generation of packaging with biodegradable materials that can serve as substitutes for conventional packaging. Polysaccharides are reliable sources of edible packaging materials with excellent renewability, biodegradability, and bio-compatibility as well as antioxidant and antimicrobial activities. Apart from these properties, packaging film developed from a single polysaccharide has various disadvantages due to undesirable properties. Thus, to overcome these problems, researchers focused on ternary blend-based bio-packaging instead of the primary and binary complex to improve their characteristics and properties. The review emphasizes the extraction of polysaccharides and their combination with other polymers to provide desirable characteristics and physico-mechanical properties of the biodegradable film which will upgrade the green packaging technology in the future generation This review also explores the advancement of ternary blend-based biodegradable film and their application in foods with different requirements and the future aspects for developing advanced biodegradable film. Moreover, the review concludes that cellulose, modified starch, and another plant-based polysaccharide film mostly provides good gas barrier property and better tensile strength, which can be used as a safeguard of perishable and semi-perishable foods which brings them closer to replacing commercial synthetic packaging.

Fluorescence probe technique for determining the hydrophobic interactions and critical aggregation concentrations of Gleditsia microphylla gum, circular Gleditsia sinensis gum, and tara gum

Circular Gleditsia sinensis gum, Gleditsia microphylla gum, and tara gum are galactomannans (GMs) with similar mannose/galactose (M/G) molar ratios, which complicates the characterization of physicochemical properties using conventional methods. Herein, the hydrophobic interactions and critical aggregation concentrations (CACs) of the GMs were compared using a fluorescence probe technique, in which the I1/I3 ratio of pyrene indicated polarity changes. With increasing GM concentration, the I1/I3 ratio decreased slightly in dilute solutions below the CAC but decreased sharply in semidilute solutions above the CAC, indicating that the GMs formed hydrophobic domains. However, increases in temperature destroyed the hydrophobic microdomains and increased the CACs. Higher concentrations of salts (SO42-, Cl-, SCN-, and Al3+) promoted hydrophobic microdomain formation, and the CACs in Na2SO4 and NaSCN solutions were lower than those in pure water. Hydrophobic microdomain formation also occurred upon Cu2+ complexation. Although urea addition promoted hydrophobic microdomain formation in dilute solutions, the microdomains were destroyed in semidilute solutions and the CACs increased. The formation or destruction of hydrophobic microdomains depended on the molecular weight, M/G ratio and galactose distribution of GMs. Therefore, the fluorescent probe technique enables the characterization of hydrophobic interactions in GM solutions, which can provide valuable insight into molecular chain conformations.

Use of fenugreek seed gum in edible film formation: major drawbacks and applicable methods to overcome

Researching on potential biopolymer sources with the aim of developing edible films with better mechanical and barrier properties has become innovative as it would be a key factor to minimize the use of synthetic polymers in food packaging. Therefore, different biopolymers such as galactomannan have been gaining attention recently. Fenugreek seed gum is a rich source of galactomannan which is minimally researched on its applicability in edible film making. The degree of galactose substitution and polymerization are the main factors that determine the functional properties of galactomannan. A strong and cohesive film matrix cannot be produced from fenugreek seed gum as its molecular interaction is weakened due to the high galactose substitution with a high galactose/mannose ratio, 1:1. Structural modifications of galactomannan in fenugreek seed gum will lead to films with the required mechanical properties. Hence, this review summarizes recent scientific studies on the limitations of fenugreek seed gum as a film forming agent and the specific modification techniques that can be applied in order to increase its film forming capability and performance.

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.

Quality-controlled LC-ESI-MS food metabolomics of fenugreek (Trigonella foenum-graecum) sprouts: Insights into changes in primary and specialized metabolites

Fenugreek (Trigonella foenum-graecum L.) is an important food and spice with bioactive compounds against diabetes. In this study, fenugreek seeds germinating in darkness for 72 h were studied using quantification of trigonelline and 4-hydroxyisoleucine and an LC-ESI-MS/MS-based metabolomic approach capable of accurately estimating 237 features from various primary and specialized compound classes. During germination, the concentrations of trigonelline and 4-hydroxyisoleucine rose by 33.5% and 33.3%, respectively. At the same time, untargeted metabolomics revealed 9 putative flavonoids increasing 1.19- to 2.77-fold compared to the dormant seeds. A set of 19 steroid saponins rose by 1.08- to 31.86-fold. Primary metabolites however showed much more variability: abundance changes in amino acid derivatives, peptides and saccharides fell in the 0.09- to 22.25-fold, 0.93- to 478.79-fold and 0.36- to 941.58-fold ranges, respectively. To increase biosynthesis of specialized metabolites during germination, sprouts were exposed to 1-100 mM methyl jasmonate (MeJA) and methyl salicylate (MeSA). The hormone treatments affected normal metabolism: 67.1-83.1 % and 64.1-83.5 % of compounds showed a reduction compared to the controls in 100 mM MeJA and MeSA treatments at different sampling time points. Contrary to expectations, the abundance of flavonoids decreased, compared to the control sprouts (0.75- and 0.68-fold change medians, respectively). The same was observed for most, but not all steroid saponins. The quality-controlled untargeted metabolomics approach proved to yield excellent insight into the metabolic changes during germination of fenugreek. The results suggest that although fenugreek germination causes major shifts in plant metabolism, there are no major qualitative changes in bioactive specialized metabolites during the first three days. This stability likely translates into good bioactivity that is similar to that of the seeds. Because the large changes in the primary metabolites likely alter the nutritive value of the seed, further studies are warranted.

A structure-property study for konjac glucomannan and guar galactomannan: Selective carboxylation and scale inhibition

The effect of structural difference for konjac glucomannan (KGM) and guar galactomannan (GGM) on their physicochemical properties including selective carboxylation, biodegradation and scale inhibition was firstly investigated. Compared with GGM, KGM can be specially modified by amino acid to prepare carboxyl-functionalized polysaccharides. The structure-activity relationship explaining the difference in carboxylation activity and the anti-scaling abilities of polysaccharides and carboxylated derivatives were explored by static anti-scaling, iron oxide dispersion and biodegradation tests coupled with structural and morphological characterizations. KGM with linear structure was preferred for carboxylated modification by glutamic acid (KGMG) and aspartic acid (KGMA) while GGM with branched structure failed to accomplish that due to steric hindrance. GGM and KGM showed limited scale inhibition performance, which was probably attributed to the moderate adsorption and isolation effect of macromolecular stereoscopic structure. While KGMA and KGMG performed as effective and degradable inhibitors for CaCO₃ scale with inhibitory efficiencies > 90 %.

Rheological properties of Sesbania cannabina galactomannan as a new source of thickening agent

The present study evaluated the rheological properties of galactomannan from Sesbania cannabina. The intrinsic viscosity of galactomannan was determined to be 8.63 ± 0.06 dl/g. Moreover, the onset of galactomannan coil overlap occurred at 5.12 ± 0.13 g/L. With increasing concentration, galactomannan showed a more distinct shear-thinning behavior, which was well characterized by the Cross model. Notably, the viscosity of polysaccharide showed a negative relationship with the temperature, while the activation energy decreased with increasing polysaccharide concentration. Furthermore, at high concentrations, the galactomannan solution showed stability after heating or freezing, as well as over the wide pH range of 5.0-9.0. Dynamic viscoelasticity measurements reveal a gradual transition from viscous to elastic behavior of galactomannans with an increasing frequency. It is anticipated that S. cannabina galactomannan will find interesting applications as a natural thickener due to the comprehensive description of its rheological properties presented herein. PRACTICAL APPLICATION: The investigated S. cannabina galactomannan has shown a higher viscosity and heat stability at high concentration, as well as a good stability at the pH range of 5-9. The S. cannabina galactomannan may be employed as stabilizers in the food field.

Changes in Structural and Rheological Properties of Guar Gum Particles in Fluidized-Bed Agglomeration: Effect of Sucrose Binder Concentration

Fluidized-bed agglomeration (FBA) is known to modify the structure and rheology of food powders. In this study, guar gum (GG) powders with various concentrations of sucrose binder (0%, 10%, 20%, or 30%) were subjected to fluidized-bed agglomeration. Subsequently, changes in the characteristics of the GG powders were evaluated by using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size distribution (PSD) analysis, and rheological and dispersibility measurements. SEM images and FTIR spectra revealed surface morphology changes and structural modification, respectively, in the original GG powder after FBA, although the changes observed in FTIR spectra were only slightly dependent on sucrose concentration at low concentrations (0–20%). XRD patterns confirmed that the crystallinity of the GG powder was affected by FBA, but not greatly so by binder concentration. The PSD results showed that the GG particle size was increased by FBA and there was a clear relationship between sucrose concentration (10–30%) and mean particle size. The rheological behavior and dispersibility of GG (properties that are known to be affected by the structure of a powder) were also influenced by sucrose concentration. To sum up, FBA and the concentration of sucrose binder used can serve as factors for modifying GG powder.

Characterization of hydrophobic interaction of galactomannan in aqueous solutions using fluorescence-based technique

Fluorescence probing was used to study hydrophobic interactions of galactomannan (GM) obtained from fenugreek gum (FG), guar gum (GG), and locust bean gum (LBG) at different M/G ratios. The I₁/I₃ ratio of pyrene changed from 1.73 to 1.29, 1.22, and 1.29 for FG, GG and LBG, respectively, as the concentration of GM increased from 0.01 to 8.0 g/L at 30 °C. The critical aggregation concentration of FG, GG, and LBG increased from 1.04 to 3.84 g/L, 1.15 to 3.73 g/L, and 0.94 to 3.63 g/L, respectively, as temperature increased from 10 to 70 °C. Addition of Na₂SO₄ and NaSCN increased the I₁/I₃ ratio in dilute solution, but reduced it in semi-dilute solution, whereas adding urea reduced I₁/I₃ in dilute solution but increased it in semi-dilute solution. These results indicated that the CAC of GM, polarity and number of hydrophobic microdomains were highly dependent on the M/G ratio and galactose distribution.

Macromolecular and thermokinetic properties of a galactomannan from Sophora alopecuroides L. seeds: A study of molecular aggregation

The molecular aggregation of a galactomannan (NSAP-25) from Sophora alopecuroides L. seeds was investigated, where three polydisperse systems were confirmed during particle size analysis, indicating existence of different aggregates composed of random coil chains revealed by circular dichroism. Morphologically, NSAP-25 aggregate of various sizes (200-1200 nm) was possibly multi-stranded and formed by ellipsoid-like particles (20-60 nm) composed of compact coil chain, exhibiting extended amorphous structure with chain-like branches intertwined. Hence, NSAP-25 aggregation was inevitable, which exerted an unignorable effect on augmenting flexibility (β↓, γ↓, α↓ and L_p/M_L↓) and compactness (ρ↓, d_f↑ and C_∞↓) of branched random coil chain based on macromolecular analysis, especially when concentration increased. Moreover, it could be relevant to thermokinetic behavior of random nucleation and subsequent growth (A² model and negative ΔS*) as well as good thermal stability (IPDT, ITS, t_0.05, T_m and T_p), thus conferring potential applications for NSAP-25 in food and pharmaceutical industries.

Diosgenin and galactomannans, natural products in the pharmaceutical sciences

Background

Diosgenin is an isospirostane derivative, which is a steroidal sapogenin and the product of acids or enzymes hydrolysis process of dioscin and protodioscin. Galactomannans are heteropolysaccharides composed of D-mannose and D-galactose, which are major sources of locust bean, guar, tara and fenugreek.

Methods

Literature survey was accomplished using multiple databases including PubMed, Science Direct, ISI web of knowledge and Google Scholar.

Results

Four major sources of seed galactomannans are locust bean (Ceratonia siliqua), guar (Cyamopsis tetragonoloba), tara (Caesalpinia spinosa Kuntze), and fenugreek (T.foenum-graecum). Diosgenin has effect on immune system, lipid system, inflammatory and reproductive systems, caner, metabolic process, blood system, blood glucose and calcium regulation. The most important pharmacological benefits of galactomannan are antidiabetic, antioxidant, anticancer, anticholinesterase, antiviral activities, and appropriate for dengue virus and gastric diseases.

Conclusions

Considering the importance of diosgenin and galactomannans, the obtained findings suggest potential of diosgenin and galactomannans as natural products in pharmaceutical industries.