Physicochemical and rheological properties of aqueous Tara gum solutions

Injectable extracellular matrix-mimetic hydrogel based on electrospun Janus fibers

To date, the reported injectable hydrogels have failed to mimic the fibrous architecture of the extracellular matrix (ECM), limiting their biological effects on cell growth and phenotype. Additionally, they lack the micro-sized pores present within the ECM, which is unfavorable for the facile transport of nutrients and waste. Herein, an injectable ECM-mimetic hydrogel (IEMH) was fabricated by shortening and dispersing Janus fibers capable of self-curling at body temperature into pH 7.4 phosphate buffer solution. The IEMH could be massively prepared through a side-by-side electrospinning process combined with ultraviolet irradiation. The IEMHs with only 5 wt% fibers could undergo sol-gel transition at body temperature to become solid gels with desirable stability, sturdiness, and elasticity and self-healing ability. In addition, they possessed notable pseudoplasticity, which is beneficial to injection at room temperature. The results obtained from characterization analysis via scanning electron microscopy, total internal reflection fluorescence microscopy, nuclear magnetic resonance spectroscopy, and Fourier-transform infrared spectroscopy indicate that their sol-gel transition under physiological conditions stems from the synergistic action of the tight entanglements between thermally-induced self-curling fibers and the hydrophobic interaction between the fibers. An MTT assay using C2C12 myoblast cells was performed to examine the in vitro cytotoxicity of IEMHs for biomedical applications, and the cell viability was found to be more than 95%.

Development of 3D printed k-carrageenan-based gummy candies modified by fenugreek gum: Correlating 3D printing performance with sol-gel transition

Temperature-responsive inks were formulated using k-carrageenan, fenugreek gum (FG), rose extracts, and sugar, of which the first two were used as the gelling agents. The interactions among components in these mixed ink formulations were investigated. Sol-gel transition and rheological properties of these inks were also correlated with extrusion, shape formation, and self (shape)-supporting aspects of 3D printing. Results indicated that incorporating FG increased inks' gelation temperature from 39.7 °C to 44.7-49.6 °C, affecting the selection of printing temperature (e.g., 0 % FG: 40 °C, 0.15 % FG: 45 °C, 0.3 % FG-0.6 % FG: 50 °C). Inks in solution states with lower viscosity (<5 Pa·s) were amenable to ensure their smooth extrusion through the tip of the printing nozzle. A shorter sol-gel transition time (approximately 100 s) during the shape formation stage facilitated the solidification of inks after extrusion. The addition of FG significantly (p<0.05) improved the mechanical properties (elastic modulus, hardness, etc.) of the printed models, which facilitated their self-supporting behavior. Low field nuclear magnetic resonance indicated that the inclusion of FG progressively restricted water mobility, consequently reducing the water syneresis rate of the mixed inks by 0.86 %-3.6 %. FG enhanced hydrogen bonding interactions among the components of these mixed inks, and helped to form a denser network.

Seed gum-based polysaccharides hydrogels for sustainable agriculture: A review

Globally, water scarcity in arid and semiarid regions has become one of the critical issues that hinder sustainable agriculture. Agriculture, being a major water consumer, presents several challenges that affect water availability. Hydrogels derived from polysaccharides seed gums are hydrophilic polymers capable of retaining substantial moisture in their three-dimensional network and releasing it back into the soil during drought conditions. Implementation of hydrogels in the agricultural sectors enhances soil health, plant growth, and crop yield. Furthermore, the soil permeability, density, structure, texture, and rate of evaporation and percolation of water are modified by hydrogel. In this review, hydrogels based on natural plant seed gum like guar, fenugreek, Tara and locust beans have been discussed in terms of their occurrence, properties, chemical structure, method of synthesis, and swelling behavior. The focus extends to recent applications of modified seed gum-based natural hydrogels in agriculture, serving as soil conditioners and facilitating nutrient delivery to growing plants. The swelling behavior and inherent structure of these hydrogels can help researchers unravel their maximum possibilities to promote sustainable agriculture and attenuate the obstacles propounded by our dynamic nature. The current review also examines market growth, prospects, and challenges of eco-friendly hydrogels in recent times.

State-of-the-art advancement in tara gum polysaccharide (Caesalpinia spinosa) modifications and their potential applications for drug delivery and the food industry

In preference to synthetic or petroleum-based materials, current research in food and pharmaceutical industries has focused on the development of biodegradable and sustainable materials due to their low toxicity, and biocompatibility. In particular, the natural water-soluble polysaccharide tara gum (Caesalpinia spinosa) has been widely used as a food-grade and drug-delivery agent due to its biodegradability, and biocompatibility. Moreover, owing to its easily modifiable hydroxy groups, tara gum, and its derivatives have been employed as food packaging films and pharmaceutical materials. In the present critical review, facile grafting methods of tara gum are reviewed, and an up-to-date comprehensive application of tara gum polysaccharides revealed their uses in pH-sensitive food packaging. In addition, modified tara gum materials exhibited improved drug delivery applications with biocompatible properties. The non-toxic nature and non-Newtonian, pseudoplastic rheological properties as well as the synergistic behavior of tara gum with other polysaccharides explore its further industrial applications in several fields. Additionally, several approaches for improving tara gum for use as a stabilizer and thickener for food items, and monitoring food spoilage, have provided notable customized characteristics. In brief, its many advantages make tara gum polysaccharide a promising material for applications in the food and pharmaceutical industries.

Molecular characterization of a galactomannan extracted from Tara (Caesalpinia spinosa) seeds

Tara gum (TG) is a polysaccharide extracted from the seeds of a South American tree called Tara (Caesalpinia spinosa). TG is a galactomannan with many applications in the food industry, mainly as an emulsifier and stabilizer agent. In addition, it is also used in the paper and cosmetic industries. In the present study, we performed a molecular characterization based on chemical composition and physicochemical properties to understand the properties behind TG applications. TG was extracted and purified from Tara seeds distributed in different ecoregions of Bolivia. The monosaccharide composition analysis was determined by high-performance anion-exchange chromatography/pulsed amperometric detection (HPAEC-PAD). At the same time, their molecular characteristics, such as molar mass, root-mean-square radius, hydrodynamic radius, conformation, and densities, were studied by asymmetrical flow field-flow fractionation coupled to multi-angle light scattering refractive index (AF4-MALS-dRI), also the specific refractive index increment (dn/dc) was determined for the first time using AF4 for TG. The results revealed that the gum samples are galactomannans composed of mannose (Man) and galactose (Gal) in a ratio of 3.37 (Man/Gal), with an average molar mass range from 2.460 × 107 to 3.699 × 107 Da, distributed in a single population. The root-mean-square radius range from 260.4 to 281.6 nm, and dn/dc is 0.1454. The Kratky plots based on 14 scattering angles indicated that the conformation of all samples corresponds to random coil monodisperse, while their gyration radius/hydrodynamic radius ratio (ρ) is high. All these results suggest that the chains have a low branched density, consistent with the Gal/Man composition. To the best of our knowledge, we report for the first time an integrated physicochemical study of TG relevant to developing emulsifier and stabilizer formulations.

Construction of Probiotic Double-Layered Multinucleated Microcapsules Based on Sulfhydryl-Modified Carboxymethyl Cellulose Sodium for Increased Intestinal Adhesion of Probiotics and Therapy for Intestinal Inflammation Induced by Escherichia coli O157:H7

The decreased number of viable bacteria and the ability of Bifidobacterium to adhere to and colonize the gut in the gastrointestinal environment greatly limit their efficacy. To solve this problem, thiolated carboxymethyl cellulose sodium (CMC) probiotic double-layered multinucleated microcapsules with Bifidobacterium adolescentis FS2-3 in the inner layer and Bacillus subtilis SN15-2 embedded in the outer layers were designed. First, the viable counts and release rates of microcapsules were examined by in vitro simulated digestion assays, and it was found that microcapsules were better protected from gastrointestinal digestion than the controls. Compared with free Bifidobacterium strains, double-layered multinucleated microcapsules have higher viable bacterial survival rates and storage stability. Second, through in vitro rheology, tensile tests, isotherm titration calorimetry, and adhesion tests, it was observed that thiolated CMC could enhance the strong interaction of Bifidobacterium with intestinal mucus and significantly promote the proliferation and growth of probiotics. Finally, double-layered multinucleated microcapsules containing B. adolescentis FS2-3 and B. subtilis SN15-2 modified with sulfhydryl-modified CMC were studied in the intestine. Alleviation of Escherichia coli O157:H7 induced intestinal inflammation. The results showed that microencapsulation could significantly increase the colon content of Bifidobacterium, relieve intestinal inflammation symptoms in mice with bacterial enteritis, and repair the intestinal microbiota disorder caused by inflammation. The probiotic double-layered multinucleated microcapsules prepared in this study can improve the survival rate of probiotics and promote proliferation, adhesion, and colonization of probiotics.

The effect of periodate oxidation of basil seed gum and its addition on protein binding

This study attempted to determine the best point of basil seed oxidation by applying response surface methodology (RSM) with 3 factors of temperature (35-45 °C), pH (3-7) as well as time (3-7 h), at 3 levels. The produced dialdehyde basil seed gum (DBSG) was collected and its physicochemical properties were determined. Fitting of quadratic, linear polynomial equations was subsequently done by considering the insignificant lack of fit, as well as highly considerable R², in order to probe the probable relationship existing between these considered variables as well as the obtained responses. So the considered optimal related test conditions, which included pH = 3, T = 45 °C as well as Time = 3 h, were specified to produce the highest percentage of aldehyde (DBSG32), optimal (DBSG34) and the (DBSG74) samples with the highest viscosity. The results obtained by FTIR and aldehyde content determination provided the indication that dialdehyde groups were formed in a way that was in equilibrium with the considered the hemiacetal form which was dominant. Furthermore, AFM investigation related to the considered DBSG34 sample displayed over-oxidation as well as depolymerization; this might be due to the enhanced hydrophobic qualities, as well as the decreased viscosity. While the DBSG34 sample had the most dialdehyde factor group with a particular tendency for the combination having the proteins' amino group, DBSG32 and DBSG74 samples could be desirable for industrial uses owing to no overoxidation.

Insights into the remarkable attenuation of hen egg white lysozyme amyloid fibril formation mediated by biogenic gold nanoparticles stabilized by quercetin-functionalized tara gum

Aberrant protein misfolding and/or aggregation and fibrillation has been linked to the pathogenesis of several debilitating chronic diseases including Alzheimer's and Parkinson's disease. Inhibiting protein amyloidogenesis has been proposed as a viable strategy to prevent or ameliorate associated disorders. Herein, we investigated the anti-amyloidogenic properties of biogenic gold nanoparticles (QTG-GNP) prepared via a simple green chemistry route and stabilized by quercetin-functionalized tara gum (QTG). The synthesized QTG-GNP was extensively characterized for its physicochemical attributes via UV-visible spectroscopy, TEM, FESEM, EDX, DLS/Zeta potential, FTIR, RAMAN, XRD, XPS, and TGA analyses, as well as for its biological properties. The results revealed that small-sized (5.01 ± 1.17 nm), well-dispersed, highly stable and round-shaped biogenic gold nanoparticles were successfully synthesized at room temperature with QTG as the sole reductant /stabilizer. Importantly, QTG-GNP demonstrated potent anti-aggregation and fibrillation inhibitory effects against amyloidogenic hen egg white lysozyme (HEWL). Also, QTG-GNP was able to dissociate pre-formed HEWL amyloid fibrils. Furthermore, the constructed nanoparticles exhibited potent anti-radical activities against DPPH and ABTS⁺ and were cytocompatible with mouse L929 fibroblast cells. On the basis of these findings, it was established that QTG-GNP holds strong prospects for further development as an agent for countering protein aggregation and associated disease conditions.

Modification of chicha gum: Antibacterial activity, ex vivo mucoadhesion, antioxidant activity and cellular viability

The aim of the present work was to modify the exuded gum of Sterculia striata tree by an amination reaction. The viscosity and zero potential of the chicha gum varied as a function of pH. The modification was confirmed by X-ray diffraction (XRD), infrared spectroscopy (FTIR), size exclusion chromatography (SEC), zeta potential, thermogravimetric analysis (TG), and differential scanning calorimetry (DSC). Furthermore, the chemical modification changed the molar mass and surface charge of the chicha gum. In addition, the gums were used in tests for ex vivo mucoadhesion strength, antibacterial activity against the standard strain of Staphylococcus aureus (ATCC 25923), inhibitory activity of α-glucosidase, antioxidant capacity, and viability of Caco-2 cells. Through these tests, it was found that amination caused an increase in the mucoadhesive and inhibitory activity of chicha gum against the bacterium Staphylococcus aureus. In addition, the gums (pure and modified) showed antioxidant capacity and an inhibitory effect against the α-glucosidase enzyme and did not show cytotoxic potential.

Isolation of a New Polysaccharide from Dandelion Leaves and Evaluation of Its Antioxidant, Antibacterial, and Anticancer Activities

Dandelion, in China, has a long history as a medicinal and edible plant, and possesses high nutritional and medical value. The present study aimed to isolate a new polysaccharide (DLP-3) from dandelion leaves and to evaluate its antioxidant, antibacterial, and anticancer activities. The structure of DLP-3 was analyzed using HPLC, FT-IR, SEM, GC-MS, and NMR spectroscopy. DLP-3 mainly consisted of Man, Rha, GlcA, Glc, Gal, and Ara with molar ratios of 2.32, 0.87, 1.21, 3.84, 1.00, and 1.05, respectively, with a molecular weight of 43.2 kDa. The main linkages of DLP-3 contained (1→4)-α-d-Glc, (1→4,6)-α-d-Glc, (1→6)-α-d-Gal, (1→2)-α-d-Man, (1→4)-α-d-Man, β-l-Ara-(1→, and α-l-Rha-(1→. DLP-3 exhibited a smooth surface, purely flake-like structure, and a triple helix conformation. Moreover, DLP-3 presented obvious antioxidant and antibacterial activities in a concentration-dependent manner. DLP-3 showed significant anticancer activities by inhibiting tumor cell proliferation. These findings provide a theoretical basis for the application of DLP-3 as a natural functional active substance in functional foods.

Shear Viscosity Overshoots in Polymer Modified Asphalts

Polymer modification is one of the most common methods for improving the performance of asphalt binders. Despite in-depth research, the structural modifications induced by polymers are still not well understood. In this work, steady shear viscosity measurements and cryo-scanning electron microscopy (cryo-SEM) were used to better understand the internal structure of asphalts modified by styrene-butadiene-styrene with and without sulfur as a crosslinking agent, asphalts modified by polyphosphoric acid (PPA), and quaternary asphalt blends modified by SBS, sulfur, and PPA. The results showed that polymer and asphaltenes collaborate, thus SBS forms a three-dimensional network strengthened by asphaltenes clusters. The strength, extension, and physical nature of such a network is revealed by the appearance of overshoots in the viscosity curves. Moreover, the indirect information deduced from the magnitude and shape of the shear viscosity curves successfully correlated with direct observations of the internal structure by cryo-SEM. Steady shear viscosity is thus recommended as a useful tool in studying the structural development of asphalts modified by different technologies.

A Comparative Evaluation of the Structural and Biomechanical Properties of Food-Grade Biopolymers as Potential Hydrogel Building Blocks

The aim of this study was to conduct a comparative assessment of the structural and biomechanical properties of eight selected food-grade biopolymers (pea protein, wheat protein, gellan gum, konjac gum, inulin, maltodextrin, psyllium, and tara gum) as potential hydrogel building blocks. The prepared samples were investigated in terms of the volumetric gelling index, microrheological parameters, physical stability, and color parameters. Pea protein, gellan gum, konjac gum, and psyllium samples had high VGI values (100%), low solid−liquid balance (SLB < 0.5), and high macroscopic viscosity index (MVI) values (53.50, 59.98, 81.58, and 45.62 nm−2, respectively) in comparison with the samples prepared using wheat protein, maltodextrin, and tara gum (SLB > 0.5, MVI: 13.58, 0.04, and 0.25 nm−2, respectively). Inulin had the highest elasticity index value (31.05 nm−2) and MVI value (590.17 nm−2). The instability index was the lowest in the case of pea protein, gellan gum, konjac gum, and inulin (below 0.02). The color parameters and whiteness index (WI) of each biopolymer differed significantly from one another. Based on the obtained results, pea protein, gellan gum, konjac gum, and psyllium hydrogels had similar structural and biomechanical properties, while inulin hydrogel had the most diverse properties. Wheat protein, maltodextrin, and tara gum did not form a gel structure.

Twin-Screw Extrusion of Oat: Evolutions of Rheological Behavior, Thermal Properties and Structures of Extruded Oat in Different Extrusion Zones

Further investigation of material properties during the extrusion process is essential to achieve precise control of the quality of the extrudate. Whole oat flour was used to produce low moisture puffed samples by a twin-screw extruder. X-ray diffraction (XRD), Scanning electron microscopy (SEM), infrared spectroscopy (FTIR), thermal analysis, and rheological experiments were used to deeply characterize changes in the structure and cross-linking of oats in different extrusion zones. Results indicated that the melting region was the main region that changed oat starch, including the major transformation of oat starch crystal morphology and the significant decrease of enthalpy representing the starch pasting peak in the differential scanning calorimeter (DSC) pattern (p < 0.05). Moreover, the unstable structure of the protein increased in the barrel and then decreased significantly (p < 0.05) after being extruded through the die head. The viscosity of oats increased in the cooking zone but decreased after the melting zone. A transformation occurred from elastic-dominant behavior to viscoelastic-dominant behavior for oats in the melting zone and after being extruded. This study provides further theoretical support for the research of the change of materials during extrusion and the development of oat-based food.

One-pot biofabrication and characterization of Tara gum/Riceberry phenolics-silver nanogel: A cytocompatible and green nanoplatform with multifaceted biological applications

This work proposed a one-pot green route for the development of a biocompatible Tara gum-Riceberry phenolics‑silver nanosphere hybrid nanocomposite (TG/RiPE-SNG) with manifold biological potentialities. The reaction system comprised of AgNO₃ as nanosilver precursor, Riceberry phenolic extract as the green in situ reductant, and Tara gum as stabilizing and anchoring agent. TG/RiPE-SNG was extensively characterized using UV-vis spectroscopy, FTIR, RAMAN, TEM, FESEM, EDX, DLS/zeta potential, XRD, and TGA analyses. Small, stable, spherical, well-dispersed SNP with an average particle size of 13.01 nm and λ_max of 421 nm were synthesized in situ, and uniformly distributed within the gel-like TG/RiPE composite. The prepared nanocomposite demonstrated superior antibacterial properties (MIC of 12.5 μg/mL) against S. aureus and S. epidermidis compared to the gum or extract. Additionally, TG/RiPE-SNG exhibited strong light barrier, tyrosinase inhibitory and antioxidant functionalities. TG/RiPE-SNG also exhibited high stability at different pH and was more thermally stable relative to the plain TG/RiPE composite. Furthermore, TG/RiPE-SNG showed good biocompatibility towards mouse L929 fibroblasts and rat erythrocytes. The obtained findings revealed a simple, benign, and inexpensive approach using only natural ingredients for the preparation of gum-based biopolymer-nanosilver hybrid nanocomposite and underscored the strong attributes of TG/RiPE-SNP as a nanomaterial with desirable biomedical potentials.

A Tara Gum/Olive Mill Wastewaters Phytochemicals Conjugate as a New Ingredient for the Formulation of an Antioxidant-Enriched Pudding

Olive mill wastewater, a high polyphenols agro-food by-product, was successfully exploited in an eco-friendly radical process to synthesize an antioxidant macromolecule, usefully engaged as a functional ingredient to prepare functional puddings. The chemical composition of lyophilized olive mill wastewaters (LOMW) was investigated by HPLC-MS/MS and ¹H-NMR analyses, while antioxidant profile was in vitro evaluated by colorimetric assays. Oleuropein aglycone (5.8 μg mL^-1) appeared as the main compound, although relevant amounts of an isomer of the 3-hydroxytyrosol glucoside (4.3 μg mL^-1) and quinic acid (4.1 μg mL^-1) were also detected. LOMW was able to greatly inhibit ABTS radical (IC₅₀ equal to 0.019 mg mL^-1), displaying, in the aqueous medium, an increase in its scavenger properties by almost one order of magnitude compared to the organic one. LOMW reactive species and tara gum chains were involved in an eco-friendly grafting reaction to synthesize a polymeric conjugate that was characterized by spectroscopic, calorimetric and toxicity studies. In vitro acute oral toxicity was tested against 3T3 fibroblasts and Caco-2 cells, confirming that the polymers do not have any effect on cell viability at the dietary use concentrations. Antioxidant properties of the polymeric conjugate were also evaluated, suggesting its employment as a thickening agent, in the preparation of pear puree-based pudding. High performance of consistency and relevant antioxidants features over time (28 days) were detected in the milk-based foodstuff, in comparison with its non-functional counterparts, confirming LOWM as an attractive source to achieve high performing functional foods.

Natural Gums as Oleogelators

The natural gums used as high molecular weight oleogelators are mainly polysaccharides that deliver a broad spectrum of possible utilization methods when structuring liquid fats to solid forms. The review discusses a natural gums’ structuring and gelling behavior to capture the oil droplets and form the water/oil gelling emulsions basing on their structural conformation, internal charge, and polymeric characteristics. The specific parameters and characteristics of natural gums based oleogels are also discussed. In the future, oleogels may eliminate saturated and trans fats from food products and allow the production of low-fat products, thus reducing the environmental damage caused by the excessive use of palm oil. The increasing knowledge of molecular interaction in polysaccharide chains of natural gums allows to apply more sustainable and wiser strategies towards product formulation. Innovative solutions for using oleogels based on natural polysaccharide biopolymers let incorporate them into the food matrix and replace fats completely or create blends containing the source of fats and the addition of the oleogel. The profound insight into molecular characteristics of natural gums in the function of being oleogelators is presented.

Effects of enzymatic hydrolysis on the structural, rheological, and functional properties of mulberry leaf polysaccharide

Effects of enzymatic hydrolysis on the structural, rheological, and functional properties of mulberry leaf polysaccharide (MLP) were characterized in this study. The enzymatic hydrolysis of MLP raised the carbonyl, carboxyl, and hydroxyl groups from 7.21 ± 0.86 to 10.08 ± 0.28 CO/100 Glu, 9.40 ± 0.13 to 17.55 ± 0.34 COOH/100 Glu, and 5.71 ± 0.33 to 8.14 ± 0.24 OH/100 Glu, respectively. Meanwhile, an increase in thixotropic performance and structure-recovery capacities were observed in hydrolyzed MLP, while the molecular weight, surface tension, apparent viscosity, and thermal stability were decreased. An improved antioxidant activity of MLP was also achieved after the enzymatic degradation. Moreover, the hydrolyzed MLP showed greater ability to promote the growths of Bifidobacterium bifidum, Bifidobacterium adolescentis, Lactobacillus rhamnosus, and Lactobacillus acidophilus and the production of acetic acid, butyric acid, and lactic acid. The results demonstrate that enzymatic modification is a useful approach for polysaccharide processing.