Effect of xanthan structure on its interaction with locust bean gum: Toward prediction of rheological properties

State-of-the-art progress on locust bean gum polysaccharide for sustainable food packaging and drug delivery applications: A review with prospectives

Locust bean gum (LBG), a polysaccharide-based natural polymer, is being widely researched as an appropriate additive for various products, including food, gluten-free formulations, medicines, paper, textiles, oil well drilling, cosmetics, and medical uses. Drug delivery vehicles, packaging, batteries, and catalytic supports are all popular applications for biopolymer-based materials. This review discusses sustainable food packaging and drug delivery applications for LBG. Given the benefits of LBG polysaccharide as a source of dietary fiber, it is also being investigated as a potential treatment for many health disorders, including colorectal cancer, diabetes, and gastrointestinal difficulties. The flexibility of LBG polysaccharide allows it to form hydrogen bonds with water molecules, a crucial characteristic of biomaterials, and the film-forming properties of LBG are critical for food packaging applications. The extraction process of LBG plays an important role in properties such as viscosity and gel-forming properties. Moreover, there are multiple factors such as temperature, pressure, pH, etc. The LBG-based functional composite film is effective in improving the shelf life as well as monitoring the freshness of fruits, meat and other processed food. The LBG-based hydrogel is excellent carrier of drugs and can be used for slow and sustainable release of active components present in drugs. Thus, the primary goal of this review was to conduct a comprehensive evaluation of the literature with a focus on the composition, properties, processing, food packaging, and medicine delivery applications of LBG polysaccharides. Thus, we investigated the chemical composition, extraction, and characteristics of LBG polysaccharides that underlie their applications in the food packaging and medicine delivery fields.

An Innovative Methodology to Characterize, at the Molecular Scale, Interactions in Polysaccharide Aqueous Solutions

Characterizing molecular interactions at the microscopic level remains difficult and, therefore, represents a key target to better understand macromolecule and biomacromolecule behaviors in solution, alone, or in mixtures with others. Therefore, accurate characterization in liquid media, especially in aqueous solutions, without causing any perturbation of the system in which they are studied, is quite difficult. To this purpose, the present paper describes an innovative methodology based on fluorescence spectrophotometry. Two molecular fluorescent probes, namely 8-anilino-1-naphtalenesulfonic acid (ANS) and 2-benzofuryl-3-hydroxy-4(1H)-quinolone (3HQ-Bf), were selected to characterize, respectively, the dipole-dipole interactions and hydrophobic micro-domains, for the first one, and hydrogen bonding, for the second. As a support to study molecular interactions, xanthan, galactomannan, and corresponding mixtures of these substances which are well known to exhibit a synergy of interactions in well-defined mixture conditions were chosen. Once the methodology was set up, the existence of the three types of interactions in these systems was demonstrated, thus allowing the elucidation of the mechanisms of interactions at the molecular scale.

Rheological Properties and Kinetics of Gelation of Binary Polymers between Xanthan Gum and Locust Bean Gum

The synergistic interaction and gelling kinetics between xanthan gum (XG) and locust bean gum (LBG) at different mass ratios (XG/LBG 9:1, 7:3, 5:5, 3:7, 1:9) were investigated using a rheometer. The results showed that the mixtures of XG and LBG induced gel formation, and the strongest gel structure was found for the mixture of XG/LBG 3:7 according to the yield stress, storage modulus (G'), and power law parameters. Temperature ramp studies indicated that heating destroyed the gels at 55~60 °C, while cooling induced the sol-gel transition at around 52 °C for all mixtures. Structure developing rate (SDR) curves showed that XG/LBG 3:7 exhibited the highest SDR during the cooling ramp among all the samples. Non-isothermal kinetic analysis demonstrated that the gelation process of XG/LBG mixtures during cooling included two steps: a high-temperature region (55~39 °C) needing higher activation energy (Ea, 111.97 to 199.20 kJ/mol for different mixtures) and a low-temperature region (39~20 °C) needing lower Ea (74.33 to 85.31 kJ/mol), which indicated higher energy barriers to overcome at the initial stage of gel formation. The lowest Ea of 74.33 kJ/mol was found for XG/LBG 3:7 in the low-temperature region. Scanning electron microscopy (SEM) showed that the gel of XG/LBG 3:7 presented the densest entanglements. These results indicated the strongest synergism interaction occurred in XG/LBG 3:7 to form gel network structures. This study will help promote the application of XG-LBG blends to design novel food structures.

In Situ Hydrogel Polymerization to Form a Flexible Polysaccharide Synergetic Binder Network for Stabilizing SiOx/C Anodes

Today, the commercial application of silicon oxides (SiOx, 1 < x < 2) in lithium-ion batteries (LIBs) still faces the challenge of rapid performance degradation. In this work, by integrating hydrothermal and physicomechanical processes, water-soluble locust bean gum (LBG) and xanthan gum (XG) are utilized to in situ form an LBG@XG binder network to improve the performance of SiOx/C anodes. As a synergy of LBG and XG polysaccharides in hydrogel polymerization, LBG@XG can tightly wrap around SiOx/C particles to prevent plate damage. The flexible SiOx/C anode with the LBG@XG binder exhibits capacity retentions of 74.1% and 76.4% after 1000 cycles at 0.5 A g-1 and 1 A g-1, respectively. The full battery capacity remains stable for 100 cycles at 1 C and the rate performance is excellent (103 mAh g-1 at 3 C). This LBG@XG is demonstrated to be highly electronegative and has a strong attraction to SiOx/C particles, thereby reducing the expansion and increasing the stability of the SiOx/C anodes when coupled with the flexible binder network. In addition to the promising LBG@XG binder, this work also provides a research idea for developing green water-based binders suitable for application in the SiOx/C anodes of LIBs.

Structural, rheological and functional properties of ultrasonic treated xanthan gums

Xanthan gum can improve the freeze-thaw stability of frozen foods. However, the high viscosity and long hydration time of xanthan gum limits its application. In this study, ultrasound was employed to reduce the viscosity of xanthan gum, and the effect of ultrasound on its physicochemical, structural, and rheological properties was investigated using High-performance size-exclusion chromatography (HPSEC), ion chromatograph, methylation analysis, 1H NMR, rheometer, etc.. The application of ultrasonic-treated xanthan gum was evaluated in frozen dough bread. Results showed that the molecular weight of xanthan gum was reduced significantly by ultrasonication (from 3.0 × 107 Da to 1.4 × 106 Da), and the monosaccharide compositions and linkage patterns of sugar residues were altered. Results revealed that ultrasonication treatment mainly broke the molecular backbone at a lower intensity, then mainly broke the side chains with increasing intensity, which significantly reduced the apparent viscosity and viscoelastic properties of xanthan gum. The results of specific volume and hardness showed that the bread containing low molecular weight xanthan gum was of better quality. Overall, this work offers a theoretical foundation for broadening the application of xanthan gum and improving its performance in frozen dough.

Textural and Rheological Properties of Sliceable Ketchup

This study investigates the effect of different mixtures of gums [xanthan (Xa), konjac mannan (KM), gellan, and locust bean gum (LBG)] on the physical, rheological (steady and unsteady), and textural properties of sliceable ketchup. Each gum had an individually significant effect (p < 0.05) on viscosity; however, the addition of Xa in combination with other gums had a greater effect on viscosity. By increasing the use of Xa in ketchup formulations, the amount of syneresis decreased such that the lowest amount of syneresis related to the sample prepared with 50% Xa and 50% gellan. Although the use of different levels of gums did not have a significant effect on the brightness (L) and redness (a) indices (p < 0.05), the use of different ratios of gums had a significant effect (p < 0.05) on the yellowness (b) index. The effect of different levels of gums used had a significant effect only on firmness (p < 0.05), and their effects on other textural parameters were not statistically significant (p > 0.05). The ketchup samples produced had a shear-thinning behavior, and the Carreau model was the best model to describe the flow behavior. Based on unsteady rheology, G’ was higher than G” for all samples, and no crossover between G’ and G” was observed for any of the samples. The constant shear viscosity (η) was lower than the complex viscosity (η*), which showed the weak gel structure. The particle size distribution of the tested samples indicated the monodispersed distribution. Scanning electron microscopy confirmed the viscoelastic properties and particle size distribution.

Poly(ethylene oxide)/Gelatin-Based Biphasic Photocrosslinkable Hydrogels of Tunable Morphology for Hepatic Progenitor Cell Encapsulation

Macroporous hydrogels have great potential for biomedical applications. Liquid or gel-like pores were created in a photopolymerizable hydrogel by forming water-in-water emulsions upon mixing aqueous solutions of gelatin and a poly(ethylene oxide) (PEO)-based triblock copolymer. The copolymer constituted the continuous matrix, which dominated the mechanical properties of the hydrogel once photopolymerized. The gelatin constituted the dispersed phase, which created macropores in the hydrogel. The microstructures of the porous hydrogel were determined by the volume fraction of the gelatin phase. When volume fractions were close to 50 v%, free-standing hydrogels with interpenetrated morphology can be obtained thanks to the addition of a small amount of xanthan. The hydrogels displayed Young's moduli ranging from 5 to 30 kPa. They have been found to be non-swellable and non-degradable in physiological conditions. Preliminary viability tests with hepatic progenitor cells embedded in monophasic PEO-based hydrogels showed rapid mortality of the cells, whereas encouraging viability was observed in PEO-based triblock copolymer/gelatin macroporous hydrogels. The latter has the potential to be used in cell therapy.

Enhancement of Self-Healing Efficacy of Conductive Nanocomposite Hydrogels by Polysaccharide Modifiers

The proper design of a polysaccharide/hydrocolloid modifier significantly affects the conductivity, self-healing, and viscoelastic properties of nanocomposite hydrogels. Due to the presence of different functional groups, these hydrogels can participate in the covalent, hydrogen and dynamic bonding of a system. The improvement of interactions in this system can lead to the development of high-performance nanocomposite hydrogels. In this study, resilient, self-healing and self-adhesive conductive nanocomposite hydrogels were produced by multiple and diverse coordination connections between various polysaccharide-based modifiers (Arabic gum, sodium carboxymethyl cellulose, and xanthan), the poly(vinyl alcohol) (PVA) network and different graphene-based fillers. Graphene nanoplatelets (GNP), activated carbon black (ACB), and reduced graphene oxide (rGO) have distinct functionalized surfaces, which were analyzed by X-ray photoelectron spectroscopy (XPS). Furthermore, the introduction of fillers balanced the hydrogels' viscoelastic properties and electrical conductivity, providing the hydrogels with resilience, improved electrical conductivity, and extreme stretchability (5000%). The self-healing properties were analyzed using time-dependent measurements in a shear strain mode using an RSO Rheometer. The improvement in electrochemical and conductivity properties was confirmed by electrochemical impedance spectroscopy (EIS). The obtained conductive nanocomposite hydrogels design opens new possibilities for developing high-performance polysaccharide-based hydrogels with wearable electrical sensors and healthcare monitoring applications.

Synergistic studies of Cassia tora gum with xanthan and guar gum: Carboxymethyl synthesis of cassia gum-xanthan synergistic blend and characterization

The present study describes the study of synergistic behavior of the Cassia tora (CTG) gum with xanthan gum (XG) and comparison with CTG and guar gum (GG) at varying temperatures. A carboxymethyl derivative of CTG: XG blend, having synergistic activity was synthesized and the reaction conditions were optimized using Taguchi's L'9 statistical design. The effect of solvent medium on the degree of substitution (DS) and the gelling property was also studied. The results reveal that synergistic interaction was found in the CTG: XG mixture whereas CTG: GG blend did not show synergistic behavior. The CTG: XG blend shows a highly viscous solution having 8371.9 cps viscosity at ambient temperature and gel is obtained by heating the blending solution and thereafter lowering the temperature. In continuum, an optimized carboxymethyl derivative (DS 0.16) also exhibits gelling properties. The carboxymethyl derivative was characterized by ¹H NMR, FTIR spectroscopy and FESEM analysis. The synergistic action of gums may be utilized in food, cosmetics and pharmaceutical applications.

Heat- and shear-reversible networks in food: A review

While nature behaves like an irreversible network with respect to entropy and time, certain systems in nature exist that are, to some extent, reversible. The property of reversibility imparts unique benefits to systems that possess them, making them suitable for designing self-healing, stimuli-responsive, and smart materials that can be used in widely divergent fields. Reversible networks are currently being exploited for applications in tissue engineering, drug delivery, and soft robotics. They are also being utilized as low-calorie fat mimetics with melt-in-your-mouth textures, as well as being explored as potential scaffolds for three-dimensional (3D) printable food, among other applications. This review aims to gather representative examples of heat- and shear-reversible networks in the food science literature from the last 30 or so years, in other words, reversible food gels made either from linear biopolymers or from colloidal, particulate dispersions, including those that have been modified specifically to induce reversibility. An overview of the network mechanisms involved that impart reversibility, including a discussion of the strength and range of forces involved, will be highlighted. A model that explains why certain networks are thermoreversible while others are shear-reversible, and why others are both, will also be proposed. A fundamental understanding of these mechanisms will prove invaluable when designing reversible networks in the future, making possible the precise control of their properties, thus fostering innovative applications within the food industry and beyond.

An overview of factors affecting the quality of beef meatballs: Processing and preservation

Beef meatball (BM) is a traditional delicious snack with rich nutrition and unique flavor, making it a preferred choice for most consumers. However, the quality of BM is easily affected by many factors, such as the processing, storage, and preservation, which limit the competitive positioning with respect to its market. Therefore, it is essential to pay attention to each step during the processing of BMs. Based on previous studies, this systematic review focuses on the effect of key processing factors (including raw materials and ingredients, beating, cooking methods, storage, and preservation) on the quality of BMs. Additionally, this study assessed the effect of each process factor on the physicochemical, sensory, nutritional, and safety attributes of BMs. Finally, the existing review will be beneficial in examining/describing the factors impacting the quality of BMs during processing, which would provide theoretical reference and scientific basis for the standardization and industrialization of BMs.

Scaffolds for Cultured Meat on the Basis of Polysaccharide Hydrogels Enriched with Plant-Based Proteins

The world population is growing and alternative ways of satisfying the increasing demand for meat are being explored, such as using animal cells for the fabrication of cultured meat. Edible biomaterials are required as supporting structures. Hence, we chose agarose, gellan and a xanthan-locust bean gum blend (XLB) as support materials with pea and soy protein additives and analyzed them regarding material properties and biocompatibility. We successfully built stable hydrogels containing up to 1% pea or soy protein. Higher amounts of protein resulted in poor handling properties and unstable gels. The gelation temperature range for agarose and gellan blends is between 23-30 °C, but for XLB blends it is above 55 °C. A change in viscosity and a decrease in the swelling behavior was observed in the polysaccharide-protein gels compared to the pure polysaccharide gels. None of the leachates of the investigated materials had cytotoxic effects on the myoblast cell line C2C12. All polysaccharide-protein blends evaluated turned out as potential candidates for cultured meat. For cell-laden gels, the gellan blends were the most suitable in terms of processing and uniform distribution of cells, followed by agarose blends, whereas no stable cell-laden gels could be formed with XLB blends.

Utilization of xanthan to stabilize water in water emulsions and modulate their viscosity

Water in water emulsions were prepared by mixing aqueous solutions of dextran and poly(ethylene oxide) at three volume fractions. The xanthan was added to the emulsions up to 0.5 wt%. The stability of the emulsions was probed by measuring the time dependence of the transmission profiles at different centrifugal forces. At lower concentrations, xanthan partitioned to the dextran phase and strong shear-thinning was observed at higher concentrations. At lower concentrations, destabilization was caused by a combination of coalescence and creaming or sedimentation. Above 0.1 wt%, xanthan strongly increased the viscosity of the emulsions and stabilized them under gravity for at least one week. The time evolution of the emulsion microstructure was observed using confocal scanning laser microscopy. The effect of shear on the microstructure was investigated using a specific rheo-optical device. It showed the formation of thin strands that broke up into small drops after stopping the flow.

Evaluation of natural gum-based cryogels for soft tissue engineering

In this study, three natural biomaterials, Locust bean gum (LBG), Xanthan gum (XG), and Mastic gum (MG), were combined to form cryogel scaffolds. Thermal and chemical characterizations revealed the successful blend formation from LBG-XG (LX) and LBG-XG-MG (LXM) polymers. All blends resulted in macro-porous scaffolds with interconnected pore structures under the size of 400 μm. The swollen cryogels had similar mechanical properties compared with other polysaccharide-based cryogels. The mean tensile and compressive modulus values of the wet cryogels were in the range of 3.5-11.6 kPa and 82-398 kPa, respectively. The sustained release of the small molecule Kartogenin from varying concentrations and ratios of cryogels was in between 32 and 66% through 21 days of incubation. Physical, mechanical, and chemical properties make LX and LXM polysaccharide-based cryogels promising candidates for cartilage and other soft tissue engineering, and drug delivery applications.

Spray-drying encapsulation of microwave-assisted extracted polyphenols from Moringa oleifera: Influence of tragacanth, locust bean, and carboxymethyl-cellulose formulations

In this work, polyphenols from Moringa oleifera (Mor) leaves were extracted by microwave-assisted extraction (MAE) and encapsulated by spray-drying (SD). Particularly, we explored the influence of tragacanth gum (TG), locust bean gum (LBG), and carboxymethyl-cellulose (CMC) as wall-materials on the physicochemical behavior of encapsulated Mor. Single or combined wall-material treatments (100:00 and 50:50 ratios, and total solid content 1%) were tested. The results showed the wall-material had a significant effect on the process yield (55.7-68.3%), encapsulation efficiency (24.28-35.74%), color (yellow or pale-yellow), total phenolic content (25.17-27.49 mg GAE g^-1 of particles), total flavonoid content (23.20-26.87 mg QE g^-1 of particles), antioxidant activity (DPPH^• = 5.96-6.95 mg GAE g^-1; ABTS^•+ = 5.61-6.18 mg TE g^-1 of particles), and particle size distribution (D₅₀ = 112-1946 nm) of the encapsulated Mor. On the other hand, SEM analysis showed smooth and spherical particles, while TGA and DSC analyses confirmed the encapsulation of bioactive compounds based on the changes in thermal peaks. Finally, XRD analysis showed that the particles have an amorphous behavior. The encapsulated Mor produced with individual TG or CMC demonstrated better properties than those obtained from mixed gums. Thus, TG or CMC might be feasible wall materials for manufacturing encapsulated Mor that conserve the phenolic content and antioxidant activity.

Impact of the synergistic interaction between xanthan and galactomannan on the stickiness properties of residual film after application on a surface

The objective was to investigate the influence of synergism between xanthan gum (X) and galactomannans (guar gum (G) and locust bean gum (L)) on the stickiness of the film formed after the application of polysaccharides on a surface. The adhesion of the film was evaluated using a texture analyzer. X, G, and L were examined in concentrated solutions (0.5, 1 and 1.5 %, w/w) and as a function of the gums mixing ratios (0/100, 20/80, 40/60, 50/50, 60/40, 80/20 and 100/0). The film stickiness increased significantly with gum concentration with G exhibiting less sticky films than with X and L. The binary mixture of X/G and X/L confirmed a synergistic interaction, increasing the firmness of mixtures and decreasing the film stickiness. Such findings open interesting applications for skincare product development using natural texturing agents with enhanced consistency with the residual film on the skin being pleasant and not sticky.

Effect of sucrose on rheological properties of xanthan gum-locust bean gum mixtures

The effect of sucrose (0, 10, 20, 30, and 40%) on flow and dynamic rheological properties of xanthan gum (XG) mixed with locust bean gum (LBG) at different mixing ratios (100/0, 75/25, 50/50, and 0/100) were evaluated. The addition of sucrose significantly changed the flow behavior index (n), consistency index (K), storage modulus (G'), and loss modulus (G″) of XG, LBG, and XG-LBG mixtures. When XG and LBG were mixed, there was a synergistic effect on K and G' values, and 50XG/50LBG mixture exhibited stronger synergy than 75XG/25LBG mixtures. However, the addition of sucrose reduced the magnitude of the synergistic effects, indicating that the presence of sucrose in XG-LBG mixtures negatively affected the synergistic interaction between gum molecules. Sucrose may competitively inhibit the binding of gum polymers to water molecules. The rheological properties of XG, LBG, and XG-LBG mixtures were affected by the addition of sucrose in a concentration-dependent manner.

Biopolymers interaction elaborating using viscoelastic relaxation spectra, network parameters, and thermodynamic properties

Herein, oscillatory rheological measurements were performed to study the interaction behavior of xanthan gum-sage seed gum blends at different ratios (SSG-XG: 1-0, 3-1, 1-1, 1-3, 0-1), from the dynamic viscosity behavior, relaxation spectrum, fracture properties, network parameters, and thermodynamic points of view at the temperature range of 10-90°C. Then, the coefficient of the interaction of four parameters, which were obtained from the clustering technique and Han curves, were used to investigate the interaction behavior quantitatively. At 90°C, SSG showed 2.01 extent of loss modulus overshoot, which was the highest value among different gum dispersions at different temperatures, while XG showed strain softening behavior. At 10 and 90°C, SSG and 1-1 SSG-XG showed the highest spreadability reflected by the slope of loss tangent after flow point stress (tan δ_AF ) of 0.52 and 0.40, respectively. The high values of ψ parameter, which represented the Gibbs free energy change, of both 1-3 and 3-1 SSG-XG blends and the lowest entropy value of 1-3 SSG-XG, suggested that the role of entropy change in incompatibility behavior of 1-3 SSG-XG was higher than that of 3-1 SSG-XG blend. With the increase in temperature from 10 to 70°C, the XG Euclidean distance from SSG decreased, while it increased from 70 to 90°C and showed the highest Euclidean distance with XG at 10°C (3.92) and 90°C (4.05). Interaction coefficients and Han curves results showed that all blends were incompatible with the lowest antagonistic behavior for 1-1 SSG-XG dispersion at 50°C. Often, a mixture of hydrocolloids, especially xanthan gum and a galactomannan, are employed in processed foods to modify their rheological properties and cut the cost. The synergistic/non-synergistic effect of biopolymers mixture, which is invaluable from the practical and economical points of view, seems to be mainly induced by their thermodynamic status of interaction. Our former study showed that the thermodynamic indices of mixing could be probed by mechanical parameters. On the other hands, we found that the mechanical properties of materials are highly temperature dependent. Therefore, in this study, to better investigate the effect of temperature on the biopolymers interaction, first we classified all the thermodynamic and mechanical properties (relaxation spectrum, fracture properties, and network parameters) of hydrocolloids into four classes, then one parameter was selected randomly from each class. The selected parameters were employed to investigate the synergistic/non-synergistic effect at all temperature ranges by determining the interaction coefficient and decide on the best interaction temperature.

Hydrogels as a water bolus during hyperthermia treatment

The feasibility of using hydrogels as a water bolus during hyperthermia treatment was assessed. Three types of gels, high methoxyl (HM) pectin/alginate, xanthan/locust bean gum (LBG) and xanthan/LBG/agarose were evaluated based on their dielectric, rheological and mechanical properties. The most suitable, xanthan/LBG/agarose gel was further used as a water bolus in a hyperthermia array applicator. The gels composed of polysaccharides carrying low charge displayed dielectric properties close to those of water, while the dielectric properties of HM pectin/alginate gel was deemed unsuitable for the current application. The mechanical examination shows that the xanthan/LBG gel has a non-brittle behaviour at room temperature, in contrast to the agarose gel. The moduli of the xanthan/LBG gel weaken however considerably between the temperature range of 40 °C and 50 °C, reducing its potential to be used as water bolus. The ternary system of xanthan/LBG/agarose had advantageous behaviour as it was dominated by the thermal hysteresis typical of agarose upon temperature increase, but governed by the typical non-brittle behaviour of the xanthan/LBG at low temperatures. The final evaluation within the hyperthermia applicator showed excellent signal transmission from the antennas. The agarose/xanthan/LBG gel reduced the scattering of electromagnetic waves, enabled a tight closure between the body and the antennas, and offered a less bulky solution than the currently used water-filled plastic bags. The results presented here open up a new application area for hydrogels in improving heat delivery during hyperthermia treatment and other near-field microwave applications.

Linear Viscoelastic Properties of Selected Polysaccharide Gums as Function of Concentration, pH, and Temperature

Hydrocolloids have been intensively investigated due to their ability to modify the rheology of the system where they are employed. They find application as thickening and gelling agents in many food, cosmetic, and pharmaceutical preparations, due to their biocompatibility and biodegradability. The present study aims to provide an exhaustive and comprehensive viscoelastic characterization of a series of hydrocolloid formulations, as function of concentration, pH, and temperature. Glucomannan, xanthan gum, tara gum, guar gum, konjac gum, and gellan gum have been analyzed at two concentrations (0.5% w/w and 1.5% w/w), using three different pH conditions (pH 1.2, 5.5, and 6.8). Their viscoelastic properties have been monitored measuring the main rheological parameters, namely, storage modulus G' and loss modulus G'' as function of frequency, time, and temperature. The results obtained show a clear dependence of the linear viscoelastic properties of the systems on concentration and pH, while the temperature was not a critical factor. Glucomannan, xanthan gum, tara gum, and guar gum samples prepared in phosphate buffer (pH 6.8) at the final concentration of 1.5% (w/w) have been selected as the most promising systems for further investigations, exploring the possibility of combinations to improve the rheological properties. PRACTICAL APPLICATION: Glucomannan, xanthan gum, tara gum, guar gum, konjac gum, and gellan gum have been chosen among the most common thickening agents derived from plants to perform a systematic investigation of the influence of pH, concentration, and temperature on the rheological properties of their water dispersions. The data obtained may be useful for further application of these hydrogels in the nutraceutical field as thickeners, texture modifiers, emulsifiers, stabilizers, and gelling agents.

κ-Carrageenan/locust bean gum as hard capsule gelling agents

A novel gelling agent, comprising blended κ-carrageenan (κ-C), a seaweed polysaccharide and locust bean gum (LBG), was used to prepare hard capsules. The distinct synergism between κ-C and LBG were verified by the textural profile analysis (TPA), FTIR and rheological measurement. Afterwards, films and hard capsules were prepared with the optimized LBG/κ-C blend gel. And the mechanical properties and morphology of films and hard capsules were analyzed by tensile testing and SEM, respectively. The results showed that the LBG/κ-C at 1:3 ratio could serve as an excellent gelling agent, which endowed hard capsule with the promoted mechanical properties, homogenous and smooth surface morphology. This work suggests that a novel blended LBG/κ-C gelling agent successfully prepared for hard capsules with improving physicochemical properties.