A comprehensive review on leguminous galactomannans: structural analysis, functional properties, biosynthesis process and industrial applications

Superabsorbent quaternary ammonium guar gum hydrogel with controlled release of humic acid for soil improvement and plant growth

Growing plants in karst areas tends to be difficult due to the easy loss of water and soil. To enhance soil agglomeration, water retention, and soil fertility, this study developed a physically and chemically crosslinked hydrogel prepared from quaternary ammonium guar gum and humic acid. The results showed that non-covalent dynamic bonds between the two components delayed humic acid release into the soil, with a release rate of only 35 % after 240 h. The presence of four hydrophilic groups (quaternary ammonium, hydroxyl, carboxyl, and carbonyl) in the hydrogel more than doubled the soil's water retention capacity. The interaction between hydrogel and soil minerals (especially carbonate and silica) promoted hydrogel-soil and soil‑carbonate adhesion, and the adhesion strength between soil particles was enhanced by 650 %. Moreover, compared with direct fertilization, this degradable hydrogel not only increased the germination rate (100 %) and growth status of mung beans but also reduced the negative effects of excessive fertilization on plant roots. The study provides an eco-friendly, low-cost, and intelligent system for soil improvement in karst areas. It further proves the considerable application potential of hydrogels in agriculture.

Horizontally transferred glycoside hydrolase 26 may aid hemipteran insects in plant tissue digestion

Glycoside hydrolases are enzymes that break down complex carbohydrates into simple sugars by catalyzing the hydrolysis of glycosidic bonds. There have been multiple instances of adaptive horizontal gene transfer of genes belonging to various glycoside hydrolase families from microbes to insects, as glycoside hydrolases can metabolize constituents of the carbohydrate-rich plant cell wall. In this study, we characterize the horizontal transfer of a gene from the glycoside hydrolase family 26 (GH26) from bacteria to insects of the order Hemiptera. Our phylogenies trace the horizontal gene transfer to the common ancestor of the superfamilies Pentatomoidea and Lygaeoidea, which include stink bugs and seed bugs. After horizontal transfer, the gene was assimilated into the insect genome as indicated by the gain of an intron, and a eukaryotic signal peptide. Subsequently, the gene has undergone independent losses and expansions in copy number in multiple lineages, suggesting an adaptive role of GH26s in some insects. Finally, we measured tissue-level gene expression of multiple stink bugs and the large milkweed bug using publicly available RNA-seq datasets. We found that the GH26 genes are highly expressed in tissues associated with plant digestion, especially in the principal salivary glands of the stink bugs. Our results are consistent with the hypothesis that this horizontally transferred GH26 was co-opted by the insect to aid in plant tissue digestion and that this HGT event was likely adaptive.

Recent advances in modifications of exudate gums: Functional properties and applications

Gums are high-molecular-weight compounds with hydrophobic or hydrophilic characteristics, which are mainly comprised of complex carbohydrates called polysaccharides, often associated with proteins and minerals. Various innovative modification techniques are utilized, including ultrasound-assisted and microwave-assisted techniques, enzymatic alterations, electrospinning, irradiation, and amalgamation process. These methods advance the process, reducing processing times and energy consumption while maintaining the quality of the modified gums. Enzymes like xanthan lyases, xanthanase, and cellulase can selectively modify exudate gums, altering their structure to enhance their properties. This precise enzymatic approach allows for the use of exudate gums for specific applications. Exudate gums have been employed in nanotechnology applications through techniques like electrospinning. This enables the production of nanoparticles and nanofibers with improved properties, making them suitable for the drug delivery system, tissue engineering, active and intelligient food packaging. The resulting modified exudate gums exhibit improved rheological, emulsifying, gelling, and other functional properties, which expand their potential applications. This paper discusses novel applications of these modified gums in the pharmaceutical, food, and industrial sectors. The ever-evolving field presents diverse opportunities for sustainable innovation across these sectors.

The plant cell wall-dynamic, strong, and adaptable-is a natural shapeshifter

Mythology is replete with good and evil shapeshifters, who, by definition, display great adaptability and assume many different forms-with several even turning themselves into trees. Cell walls certainly fit this definition as they can undergo subtle or dramatic changes in structure, assume many shapes, and perform many functions. In this review, we cover the evolution of knowledge of the structures, biosynthesis, and functions of the 5 major cell wall polymer types that range from deceptively simple to fiendishly complex. Along the way, we recognize some of the colorful historical figures who shaped cell wall research over the past 100 years. The shapeshifter analogy emerges more clearly as we examine the evolving proposals for how cell walls are constructed to allow growth while remaining strong, the complex signaling involved in maintaining cell wall integrity and defense against disease, and the ways cell walls adapt as they progress from birth, through growth to maturation, and in the end, often function long after cell death. We predict the next century of progress will include deciphering cell type-specific wall polymers; regulation at all levels of polymer production, crosslinks, and architecture; and how walls respond to developmental and environmental signals to drive plant success in diverse environments.

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.

Ag0-Ginger Nanocomposites Integrated into Natural Hydrogelated Matrices Used as Antimicrobial Delivery Systems Deposited on Cellulose Fabrics

In the textile, medical, and food industries, many of the applications have targeted the use of textile fabrics with antimicrobial properties. Obtaining eco-friendly coatings is of wide interest, especially for applications related to wound dressing or to food packaging. In order to obtain coatings with antimicrobial properties through environmentally friendly methods, a series of experiments were carried out on the use of natural polymers loaded with silver nanoparticles. In this study, coatings with antimicrobial properties were obtained by depositing natural composites based on rice flour, carob flour, or alginate on cotton fabrics. These antimicrobial coatings were multicomponent systems, in which the host matrix was generated via hydration of natural polymers. The nanocomposite obtained from the phytosynthesis of silver particles in ginger extract was embedded in hydrogel matrices. The multicomponent gels obtained by embedding silver nanoparticles in natural polymer matrices were deposited on cotton fabric and were studied in relation to nanoparticles and the type of host matrix, and the antimicrobial activity was evaluated. Fabrics coated with such systems provide a hydrophilic surface with antimicrobial properties and can therefore be used in various areas where textiles provide antibacterial protection.

Evaluation of Cassia fistula seed galactomannan as tablet-binder in formulation of diclofenac sodium-loaded monolithic matrix tablet

The present study aimed to evaluate Cassia fistula seed galactomannan (CFSG) as a tablet-binder in the formulation of a monolithic matrix tablet using diclofenac sodium as a model drug. Initially, CFSG was extracted and purified from the seeds of the Cassia fistula tree and then screened for phytochemicals. Native CFSG was characterized with polysaccharide content determination, monosaccharide composition analysis, elemental analysis, FTIR, solid-state 13C NMR, molecular weight, zeta potential, DSC, TGA-DTA, XRD, viscosity, pH and surface tension, rheology, SEM and acute oral toxicity study. Prior to formulation, the drug-CFSG compatibility was checked by FTIR, DSC, and XRD. Diclofenac sodium-loaded granules were prepared by the wet granulation method and evaluated for various granule properties. Finally, granules were compressed into tablets and evaluated for binding and other tablet properties. The granules showed to have optimum micromeritic properties. Tablet hardness and friability were found to be approximately 7 kg/m2 and 0.3 %, respectively, which substantiate the excellent binding capacity of CFSG. Other tablet properties were also found to be within the Pharmacopoeial compliance limit. The tablets with a minimum concentration of CFSG (2.5%w/w) as binder showed appreciable mechanical strength and faster drug release, which ratifies CFSG as an alternative tablet binder.

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.

Dietary Fiber from Soybean (Glycine max) Husk as Fat and Phosphate Replacer in Frankfurter Sausage: Effect on the Nutritional, Physicochemical and Nutraceutical Quality

The objective of the present study was to evaluate the effect of dietary fiber from soybean (glycine max) husk as fat and phosphate replacer on the nutritional, physicochemical, and nutraceutical quality of Frankfurter sausage. A traditional formulation was used for the pork-based sausage and three treatments were established: control treatment (CT), sausage without SHDF; treatment 1 (T1), sausage and 1% SHDF; treatment 2 (T2), sausage and 1.5% SHDF. T2 showed the best nutritional contribution of the treatments, significantly favoring a lower content of fat and sodium, thus increasing the contribution of dietary fiber and calcium. A positive effect of SHDF on the water-holding capacity of the treatments was also observed. In addition, T2 remained stable during storage, while T1 and CT showed significantly reduced water-holding capacities of approximately 5%; this was in turn linked to hardness, as it was observed that on day 7 of storage, 27% less force was required to deform the T2 sausages. Regarding color, no significant difference was observed with the addition of SHDF to the product. The results suggest that the dietary fiber extracted from soybean husks has potential for application in food and can be used as an ingredient to improve the functional and nutritional quality of Frankfurter sausages by reducing the content of fat and phosphates.

Biochemical analyses of a novel acidophilic GH5 β-mannanase from Trichoderma asperellum ND-1 and its application in mannooligosaccharides production from galactomannans

In this study, an acidophilic GH5 β-mannanase (TaMan5) from Trichoderma asperellum ND-1 was efficiently expressed in Pichia pastoris (a 2.0-fold increase, 67.5 ± 1.95 U/mL). TaMan5 displayed the highest specificity toward locust bean gum (K_m = 1.34 mg/mL, V_max = 749.14 μmol/min/mg) at pH 4.0 and 65°C. Furthermore, TaMan5 displayed remarkable tolerance to acidic environments, retaining over 80% of its original activity at pH 3.0-5.0. The activity of TaMan5 was remarkably decreased by Cu²⁺, Mn²⁺, and SDS, while Fe²⁺/Fe³⁺ improved the enzyme activity. A thin-layer chromatography (TLC) analysis of the action model showed that TaMan5 could rapidly degrade mannan/MOS into mannobiose without mannose via hydrolysis action as well as transglycosylation. Site-directed mutagenesis results suggested that Glu²⁰⁵, Glu³¹³, and Asp³⁵⁷ of TaMan5 are crucial catalytic residues, with Asp¹⁵² playing an auxiliary function. Additionally, TaMan5 and commercial α-galactosidase displayed a remarkable synergistic effect on the degradation of galactomannans. This study provided a novel β-mannanase with ideal characteristics and can be considered a potential candidate for the production of bioactive polysaccharide mannobiose.

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.

Properties of galactomannans and their textile-related applications-A concise review

Galactomannans are reserve carbohydrates in legume plants and are primarily extracted from their seeds. They contain galactose side chains throughout the mannose backbone and have unique features such as emulsifying, thickening, and gelling together with biodegradability, biocompatibility, and non-toxicity, which make them an appealing material. Guar gum and locust bean gum mainly are used in all galactomannan needed applications. Nonetheless, tara gum and fenugreek gum have also attracted considerable attention in recent decades. Despite the increased usage of galactomannans in the textile-related fields in recent years, there is no review article published yet. To fill this gap and to demonstrate the striking and increasing importance of galactomannans, a concise summary of the properties of common galactomannans and their comparisons is given first, followed by an account of recent developments and applications of galactomannans in the textile-related fields. The associated potential opportunities are also provided at the end of this review.

Locust Bean Gum, a Vegetable Hydrocolloid with Industrial and Biopharmaceutical Applications

Locust bean gum (LBG), a vegetable galactomannan extracted from carob tree seeds, is extensively used in the food industry as a thickening agent (E410). Its molecular conformation in aqueous solutions determines its solubility and rheological performance. LBG is an interesting polysaccharide also because of its synergistic behavior with other biopolymers (xanthan gum, carrageenan, etc.). In addition, this hydrocolloid is easily modified by derivatization or crosslinking. These LBG-related products, besides their applications in the food industry, can be used as encapsulation and drug delivery devices, packaging materials, batteries, and catalyst supports, among other biopharmaceutical and industrial uses. As the new derivatized or crosslinked polymers based on LBG are mainly biodegradable and non-toxic, the use of this polysaccharide (by itself or combined with other biopolymers) will contribute to generating greener products, considering the origin of raw materials used, the modification procedures selected and the final destination of the products.

Using One-pot Fermentation Technology to Prepare Enzyme Cocktail to Sustainably Produce Low Molecular Weight Galactomannans from Sesbania cannabina Seeds

Enzymatic hydrolysis using β-mannanase and α-galactosidase is necessary to produce low molecular weight galactomannan (LMW-GM) from galactomannans (GM) in the leguminous seeds. In this study, different ratios of avicel and melibiose were used as the inductors (carbon sources) for Trichoderma reesei to metabolize the enzyme cocktail containing β-mannanase and α-galactosidase using one-pot fermentation technology. The obtained enzyme cocktail was used to efficiently produce LMW-GM from GM in Sesbania cannabina seeds. Results showed that 15 g/L avicel and 10 g/L melibiose were the best carbon sources to prepare enzyme cocktail containing β-mannanase and α-galactosidase with activities of 3.69 ± 0.27 U/mL and 0.51 ± 0.02 U/mL, respectively. Specifically, melibiose could effectively induce the metabolite product of α-galactosidase by T. reesei, which showed good performance in degrading the galactose substituent from GM backbone. The degradation of galactose alleviated the spatial site-blocking effect for enzymatic hydrolysis by β-mannanase and improved the yield of LMW-GM. This research can lay the foundation for the industrial technology amplification of LMW-GM production for further application.

Effects of the Hofmeister anion series salts on the rheological properties of Sesbania cannabina galactomannan

Sesbania cannabina galactomannan (2%) solutions added with strongly hydrated ions (Na₂CO₃, NaH₂PO₄, NaCl) and weakly hydrated ions (NaNO₃) at different ionic strengths were rheologically characterized. The four selected salts dramatically decreased the intrinsic viscosity of galactomannan solution in the following order of effectiveness: Na₂CO₃ < NaH₂PO₄ < NaCl < NaNO₃. This conforms effectively to the Hofmeister anion series. Moreover, salt addition increased the viscosity of galactomannan solution when the ionic strength was 1 mmol/kg, which related to an increased occurrence of intermolecular interactions. As increasing ionic strength, galactomannan chains may tend to contract or expand due to the presence of strongly or weakly hydrated ions, thereby decreasing the viscosity. These phenomena were demonstrated by zeta potential measurement and again observed in dynamic viscoelasticity measurement. Overall, this property can be used to manipulate the rheological properties of galactomannan in food gums to obtain gums of high quality for enhancing consumer goods.