Gellan Gum Solutions Research Articles

Enhanced mucoadhesive properties of ionically cross-linked thiolated gellan gum films

Localized oral drug delivery offers several advantages for treating various disease conditions. However, drug retention at the disease site within the oral cavity is indeed a significant challenge due to the dynamic oral environment. The present study aimed to develop a mucoadhesive inner layer for a three-layer mucoadhesive bandage suitable for localized oral drug delivery. using gellan gum (GG) biopolymer. Gellan gum (GG) was modified using L-cysteine moieties via carbodiimide chemistry. Subsequently, gellan gum solution at different extents of thiolation was ionically cross-linked using aluminum ammonium sulfate. Thiolated gellan gum films of uniform thickness were prepared using a solvent casting method. The thickness of bare gellan gum film was 0.035 ± 0.0043 mm, whereas the thiolated gellan gum films, GG 1S and GG 2S showed a thickness of 0.0191 ± 0.0011 mm and 0.0188 ± 0.0004 mm respectively. A high work of adhesion was noted for thiolated gellan gum (GG 2S) with a value of 10 N.mm while using porcine buccal mucosa. An average tensile strength of 48.2 ± 2.46 MPa was measured for thiolated gellan gum films irrespective of the extent of thiolation. The high work of adhesion, favorable cytocompatibility, desirable mechanical properties, and free swell capacity in saline confirmed the suitability of ionically cross-linked thiolated gellan gum films as an inner mucoadhesive layer for the mucoadhesive bandage.

Development of novel protein-rich foods: Studies of composite hydrogels formed from potato proteins and gellan gums with different degrees of acylation

The textural attributes of mixed hydrogels formed from potato protein (PP) and gellan gum (GG) were examined for their potential application as novel protein-rich foods (NPFs). Initially, the properties of gels formed by the individual biopolymers were characterized using dynamic shear rheology, compression testing, and confocal fluorescence microscopy. Rheological analysis revealed that PP dispersions formed irreversible heat-set gels, whereas GG formed reversible cold-set gels at lower temperatures. The effects of adding PP to high acyl gellan gum (HA-GG) or low acyl gellan gum (LA-GG) solutions on the microstructure and rheology of the mixed gels formed were then examined. The PP/LA-GG composite gels had a highly heterogeneous microstructure consisting of protein-rich and polysaccharide-rich regions. In contrast, the PP/HA-GG composite gels had a more uniform microstructure. Interestingly, the incorporation of the PP weakened the PP/LA-GG composite gels (antagonism) but strengthened the PP/HA-GG composite gels (synergism), which was mainly attributed to their different impacts on gel microstructure. This study shows that semi-solid plant protein-dietary fiber composites can be formed with a variety of textural attributes by altering the nature and concentration of biopolymers used to formulate them. These mixed gels may be useful for the creation of NPFs. This study also highlights the complexity of the interactions between different food biopolymers and their impacts on food properties, highlighting the need for further research on understanding structure-function relationships in multicomponent biopolymer materials.

Formulation and characterization of ionically crosslinked gellan gum hydrogels using trilysine at low temperatures for antibody delivery

Research of the nontraditional polysaccharide gellan gum (GG) is a growing space for the development of novel drug delivery systems due to its tunable physic-mechanical properties, biocompatibility, and stability in a wide range of environments. Unfortunately, high temperature crosslinking is often required, representing a limiting factor for the incorporation of thermosensitive therapeutic agents. Here, we demonstrated that GG can be crosslinked at a low temperature (38 °C) using a simple fabrication process that utilizes trilysine as an alternative to traditional mono- or divalent ion crosslinkers. While elevated temperature mixing is still required to form a clear GG solution, crosslinking of 0.5 – 1 % GG (w/v) in the presence of trilysine (0.03 % - 0.05 % w/v) was achieved at 38 °C resulting in hydrogels with suitable working formulations to facilitate syringe loading. Low injection forces (< 20 N), and biocompatibility was evaluated with normal human dermal fibroblast (cell viability > 90 %). Frequency sweep showed a transition from purely liquid-like behavior to gel-like behavior with increased trilysine concentration. A temperature dependent behavior was lost with higher trilysine concentrations, indicating stable hydrogel formation. NMR results suggest that trilysine participates in gelation via both ionic interactions between the primary amines of trilysine and the carboxylate residues of glucuronic acid and hydrogen bonding. Released studies showed that GG hydrogels can entrap and provide sustained release of IgG in relation to the crosslinker, and antibody concentration used, with a burst release within the first 24 h (∼80 % cumulative released) followed by a sustained released for up to 5 days. Overall, findings demonstrate a promising nontoxic injectable hydrogel that requires lower crosslinking temperatures, is simple to manufacture and serves as a carrier of thermosensitive therapeutic agents.

Super-Transparent Soil for In Situ Observation of Root Phenotypes.

Transparent soil (TS) presents immense potential for root phenotyping due to its ability to facilitate high-resolution imaging. However, challenges related to transparency, mechanical properties, and cost hinder its development. Herein, we introduce super-transparent soil (s-TS) prepared via the droplet method using low acyl gellan gum and hydroxyethyl cellulose crosslinked with magnesium ions. The refractive index of the hydroxyethyl cellulose solution (1.345) closely aligns with that of water (1.333) and the low acyl gellan gum solution (1.340), thereby significantly enhancing the transmittance of hydrogel-based transparent soil. Optimal transmittance (98.45%) is achieved with polymer concentrations ranging from 0.8 to 1.6 wt.% and ion concentrations between 0.01 and 0.09 mol·L-1. After 60 days of plant cultivation, s-TS maintains a transmittance exceeding 89.5%, enabling the detailed visualization of root growth dynamics. Furthermore, s-TS exhibits remarkable mechanical properties, withstanding a maximum compressive stress of 477 kPa and supporting a maximum load-bearing depth of 186 cm. This innovative approach holds promising implications for advanced root phenotyping studies, fostering the investigation of root heterogeneity and the development of selective expression under controlled conditions.

Mesenchymal Stem Cell-Laden In Situ-Forming Hydrogel for Preventing Corneal Stromal Opacity.

The aims of this study were to construct a mesenchymal stem cell (MSC)-laden in situ-forming hydrogel and study its effects on preventing corneal stromal opacity. The native gellan gum was modified by high temperature and pressure, and the rabbit bone marrow MSCs were encapsulated before adding Ca 2+ to initiate cross-linking. The effects of the hydrogel on 3D culture and gene expression of the rabbit bone marrow MSCs were observed in vitro. Then, the MSC-hydrogel was used to repair corneal stromal injury in New Zealand white rabbits within 28 days postoperation. The short-chain gellan gum solution has a very low viscosity (<0.1 Pa·s) that is ideal for encapsulating cells. Moreover, mRNA expressions of 3D-cultured MSCs coding for corneal stromal components (decorin, lumican, and keratocan) were upregulated (by 127.8, 165.5, and 25.4 times, respectively) ( P < 0.05) on day 21 in vitro and were verified by Western blotting results. For the in vivo study, the corneal densitometry of the experimental group was (20.73 ± 1.85) grayscale units which was lower than the other groups ( P < 0.05). The MSC-hydrogel downregulated mRNA expression coding for fibrosis markers (α-smooth muscle actin, vimentin, collagen type 5-α1, and collagen type 1-α1) in the rabbit corneal stroma. Furthermore, some of the 5-ethynyl-2'-deoxyuridine (EdU)-labeled MSCs integrated into the upper corneal stroma and expressed keratocyte-specific antigens on day 28 postoperation. The short-chain gellan gum allows MSCs to slowly release to the corneal stromal defect and prevent corneal stromal opacity. Some of the implanted MSCs can integrate into the corneal stroma and differentiate into keratocytes.

Engineering an injectable gellan gum-based hydrogel with osteogenesis and angiogenesis for bone regeneration

Injectable hydrogels are currently a topic of great interest in bone tissue engineering, which could fill irregular bone defects in a short time and avoid traditional major surgery. Herein, we developed an injectable gellan gum (GG)-based hydrogel for bone defect repair by blending nano-hydroxyapatite (nHA) and magnesium sulfate (MgSO4). In order to acquire an injectable GG-based hydrogel with superior osteogenesis, nHA were blended into GG solution with an optimized proportion. For the aim of endowing this hydrogel capable of angiogenesis, MgSO4 was also incorporated. Physicochemical evaluation revealed that GG-based hydrogel containing 5% nHA (w/v) and 2.5 mM MgSO4 (GG/5%nHA/MgSO4) had appropriate sol-gel transition time, showed a porosity-like structure, and could release magnesium ions for at least 14 days. Rheological studies showed that the GG/5%nHA/MgSO4 hydrogel had a stable structure and repeatable self-healing properties. In-vitro results determined that GG/5%nHA/MgSO4 hydrogel presented superior ability on stimulating bone marrow mesenchymal stem cells (BMSCs) to differentiate into osteogenic linage and human umbilical vein endothelial cells (HUVECs) to generate vascularization. In-vivo, GG/5%nHA/MgSO4 hydrogel was evaluated via a rat cranial defect model, as shown by better new bone formation and more neovascularization invasion. Therefore, the study demonstrated that the new injectable hydrogel, is a favorable bioactive GG-based hydrogel, and provides potential strategies for robust therapeutic interventions to improve the repair of bone defect.

Effect of magnetic field on quality improvement of medium‐term delivery frozen pepper

AbstractThe water loss of medium‐term delivery frozen pepper is significant, resulting in the decline of product quality and the loss of nutrients. Hydrocolloids have been proved to help reduce the water loss of fruits and vegetables. Applying magnetic field can reduce the size of ice crystals during freezing, thus preventing cell damage and reducing water loss. In this study, the pickled red pepper was first soaked in gellan gum solution, and then frozen by magnetic field assisted freezing method to reduce the water loss of pepper products during storage. The process was accelerated by repeated (2–6 times) freezing and thawing, so as to reach the standard of medium‐term delivery faster. At the same time, the thawing stage was also supplemented by the action of magnetic field to explore its thawing effect. The results showed that freezing at 10 mT and −20°C and thawing at 4°C and 10 mT can better maintain the texture characteristics of pepper products compared to the control group, thereby reducing the water loss from 40% to 5%, increasing the color appeal, and reducing the loss of red pigment.Practical applicationsThis study provides a simple and novel method to reduce the water loss of frozen products during thawing. These steps combine hydrophilic colloid and magnetic field exploration to reduce the water loss of frozen products, and provide new ideas for product freezing and thawing.

Anion specific conformational change in aqueous gellan gum solutions

127I NMR is applied to investigate the motional state and the selective interaction of I− ions in tetramethylammonium form of gellan gum (TMA gellan), together with monitoring the conformational change by the optical rotation measurement. The experimental results indicate that I− ion promotes the conformational transition, and there exists the preferential affinity of I− ion for the ordered conformation of TMA gellan.

Injectable Hydrogel Based on Gellan Gum/Silk Sericin for Application as a Retinal Pigment Epithelium Cell Carrier.

The damage to retinal pigment epithelium (RPE) cells can lead to vision loss and permanent blindness. Therefore, an effective therapeutic strategy has emerged to replace damaged cells through RPE cell delivery. In this study, we fabricated injectable gellan gum (GG)/silk sericin (SS) hydrogels as a cell carrier by blending GG and SS. To determine the appropriate concentration of SS for human RPE ARPE-19, 0, 0.05, 0.1, and 0.5% (w/v) of SS solution were blended in 1% (w/v) GG solution (GG/SS 0%, GG/SS 0.05%, GG/SS 0.1%, and GG/SS 0.5%, respectively). The physical and chemical properties were measured through Fourier-transform infrared spectroscopy, scanning electron microscopy, mass swelling, and weight loss. Also, viscosity, injection force, and compressive tests were used to evaluate mechanical characteristics. Cell proliferation and differentiation of ARPE-19 were evaluated using quantitative dsDNA analysis and real-time polymerase chain reaction, respectively. The addition of SS gave GG/SS hydrogels a compressive strength similar to that of natural RPE tissue, which may well support the growth of RPE and enhance cell proliferation and differentiation. In particular, the GG/SS 0.5% hydrogel showed the most similar compressive strength (about 10 kPa) and exhibited the highest gene expression related to ARPE-19 cell proliferation. These results indicate that GG/SS 0.5% hydrogels can be a promising biomaterial for cell delivery in retina tissue engineering.

Experimental Study on the Kinetics of the Natural Gas Hydration Process with a NiMnGa Micro-/Nanofluid in a Static Suspension System

Natural gas is a resource-rich clean energy source, and natural gas hydration technology is a promising method for natural gas storage and transportation at present. To realize the rapid generation of hydrates with a high gas storage capacity, in this paper NiMnGa micro/nanoparticles (NMGs) with different mass fractions (0.1 wt%, 1 wt%, 2 wt%) were prepared with 0.05 wt% sodium dodecyl sulfate (SDS) and 1 wt% L-tryptophan to form static suspension solutions of gellan gum, and the methane hydration separation kinetics experiments were carried out under the condition of 6.2 MPa for the SDS-NMG-SNG (SNG) and L-tryptophan-NMG-LNG (LNG) systems. The results showed that the induction time of the systems with NMG micro-/nanoparticles was shortened to different degrees and the gas consumption rate was increased. The best effect was achieved in the SNG system with 1 wt% NMG, and the induction time was shortened by 73.6% compared with the SDS-gellan system (SG). The gas consumption rate of the system with L-tryptophan was better than that of the system with SDS, and the best effect was achieved in the system with 2 wt% NMG. The system with 2 wt% NMG had the best effect, and the problem of foam decomposition did not occur. The analysis concluded that NMG has strong mass transfer and phase-change heat absorption properties, which can significantly improve the kinetics of the natural gas hydrate generation process; L-tryptophan can weaken the diffusion resistance of methane molecules in the suspended static solution, further enhancing the mass transfer of the hydrate generation process. These findings will provide new perspectives regarding the application of phase-change micro-/nanoparticles in methane hydrate generation under static conditions.

The influence of Ca/Mg ratio on autogelation of hydrogel biomaterials with bioceramic compounds

Hydrogels, which are versatile three-dimensional structures containing polymers and water, are very attractive for use in biomedical fields, but they suffer from rather weak mechanical properties. In this regard, biocompatible particles can be used to enhance their mechanical properties. The possibility of loading such particles with drugs (e.g. enzymes) makes them a particularly useful component in hydrogels. In this study, micro/nanoparticles containing various ratios of Ca2+/Mg2+ with sizes ranging from 1 to 8 μm were prepared and mixed with gellan gum (GG) solution to study the in-situ formation of hydrogel-particle composites. The particles provide multiple functionalities: 1) they efficiently crosslink GG to induce hydrogel formation through the release of the divalent cations (Ca2+/Mg2+) known to bind to GG polymer chains; 2) they enhance mechanical properties of the hydrogel from 2 up to 100 kPa; 3) the samples most efficiently promoting cell growth were found to contain two types of minerals: vaterite and hydroxymagnesite, which enhanced cells proliferation and hydroxyapatite formation. The results demonstrate that such composite materials are attractive candidates for applications in bone regeneration.

Permeability reduction by gellan gum solutions

This paper summarizes the results of laboratory experiments with gellan gum. Gellan gum solutions demonstrated plugging in distilled water and brine saturated sand packs. Progressive plugging in distilled water saturated sand packs is explained by the presence of gel particles in the gellan gum solutions, whereas plugging in brine saturated sand packs is explained by the instantaneous gelation of gellan gum upon contact with brine. Gellan gum gel strength and its injectivity depend on brine salinity in the rage of 0–60 g⋅L−1. Gellan gum plugging behavior in porous media depends on polymer concentration, permeability, and temperature. However, in these tests internal pressure taps were not used, making conclusions impossible as to whether gellan gum solutions provide in-depth plugging in matrix rocks. Fracture models with an impermeable matrix and fractured sandstone cores were used in this study to compare gellan gum and hydrolyzed polyacrylamide gels. Alternating injection of gellan gum and brine demonstrated an effective way to plug 1-mm-height fractures. The plugging efficiency of polyacrylamide gel depends on the initial viscosity of the solution, if it is injected prior to gelation, and post flush salinity. Whereas in the case of gellan gum, these factors are not critical because the solution gels instantaneously upon contact with brine, with higher brine salinity improving gel strength. Although, maximal gel and post flush injection pressures were several times higher in the case of gellan gum, stabilized post flush injection pressure was higher in the case of hydrolyzed polyacrylamide gel placed as a mature gel in a sandstone fractured core.

In vitro and in vivo evaluation of an ionic sensitive in situ gel containing nanotransfersomes for aripiprazole nasal delivery

In the current study, a composite in-situ gel formulation containing aripiprazole (APZ) loaded transfersomes (TFS) was developed for the intranasal brain targeting of APZ. APZ loaded TFS were prepared by applying the film hydration method and optimized using an irregular factorial design. The prepared formulations were optimized based on different parameters including particle size, polydispersity index (PdI), zeta potential, encapsulation efficiency (EE) and release efficiency (RE). The optimized APZ-TFS were distributed in an ion-triggered deacetylated gellan gum solution (APZ-TFS-Gel) and evaluated in terms of pH, gelling time, rheological properties and in-vitro release study. The therapeutic efficacy of the best APZ-TFS-Gel was then tested in the mice model of schizophrenia induced by ketamine by evaluating various behavioral parameters. The optimized formulation showed the particle size of 72.12 ± 0.72 nm, the PdI of 0.19 ± 0.07, the zeta potential of −55.56 ± 1.9 mV, the EE of 97.06 ± 0.10%, and the RE of 70.84 ± 1.54%. The in-vivo results showed that compared with the other treatment groups, there was a considerable increase in swimming and climbing time and a decrease in locomotors activity and immobility time in the group receiving APZ-TFS-Gel. Thus, APZ-TFS-Gel was found to have desirable characteristics for therapeutic improvement.

Thermo-and pH-responsive chitosan/gellan gum hydrogels incorporated with the β-cyclodextrin/curcumin inclusion complex for efficient curcumin delivery

Thermo- and pH-sensitive hydrogels based on chitosan (CS) and gellan gum (GG) were used for efficient curcumin (CUR) delivery for the first time. β-Cyclodextrin/curcumin (βCD/CUR) inclusion complex was mixed with aqueous GG solution and associated with CS solution aliquots. CS/GG hydrogels incorporated with the βCD-CUR inclusion complex containing CS between 40 and 80 wt% were prepared by cooling CS/GG/βCD/CUR mixtures. The materials were characterized by infrared spectroscopy, thermal analysis, X-ray diffraction, scanning electron microscopy, confocal scanning microscopy, and mechanical measurements. The CS/GG-βCD-CUR ratio in the mixture significantly influenced the hydrogel properties. The pH-responsive hydrogels presented porosity between 76 and 84%, mechanical strength between 247 and 747 Pa, and disintegration rate lower than 25% in simulated intestinal fluid (SIF). The CUR release was investigated in simulated intestinal (SIF) and simulated gastric (SGF) fluids with and without lysozyme (27.8 μg/mL) and Tween 80 (1% v/v). Lysozyme and Tween 80 enhanced the CUR release in SIF, reaching 69.40% (10.10 mg/g) after 240 h. The Ritger-Peppas and Higuchi mathematical models adjusted well to the experimental CUR release kinetic curves. The materials were cytocompatible toward healthy VERO cells. This study reports durable polysaccharide-based assemblies for CUR delivery created following a method in-situ.

A Preliminary Study on Tensile Properties of Gellan Gum/KCF Biocomposite Films

In this preliminary study, kenaf core fiber (KCF) was utilized as a natural filler for the preparation of the gellan gum/KCF biocomposite films. The films were prepared by casting gellan gum solutions containing glycerol and KCF, followed by gelation and drying. The weight ratio of gellan gum and glycerol was fixed at 2:3, while the content of KCF varied from 6 to 15 wt.% relative to the weight of gellan gum. The tensile properties of the prepared films have been determined by using a universal testing machine. The tensile test results demonstrated that the tensile extension and tensile energy at break of the biocomposite films have significantly increased with the incorporation of KCF. Nevertheless, the tensile stress and tensile modulus at maximum load have drastically decreased with the increase of KCF content. This study implied that the incorporation of KCF had enhanced the ductility of the gellan gum/KCF biocomposite films and at the same time, reduced the stiffness of the films.

A Novel Gel-Forming Solution Based on PEG-DSPE/Solutol HS 15 Mixed Micelles and Gellan Gum for Ophthalmic Delivery of Curcumin.

Curcumin (Cur) is a naturally hydrophobic polyphenol with potential pharmacological properties. However, the poor aqueous solubility and low bioavailability of curcumin limits its ocular administration. Thus, the aim of this study was to prepare a mixed micelle in situ gelling system of curcumin (Cur-MM-ISG) for ophthalmic drug delivery. The curcumin mixed micelles (Cur-MMs) were prepared via the solvent evaporation method, after which they were incorporated into gellan gum gels. Characterization tests showed that Cur-MMs were small in size and spherical in shape, with a low critical micelle concentration. Compared with free curcumin, Cur-MMs improved the solubility and stability of curcumin significantly. The ex vivo penetration study revealed that Cur-MMs could penetrate the rabbit cornea more efficiently than the free curcumin. After dispersing the micelles in the gellan gum solution at a ratio of 1:1 (v/v), a transparent Cur-MM-ISG with the characteristics of a pseudoplastic fluid was formed. No obvious irritations were observed in the rabbit eyes after ocular instillation of Cur-MM-ISG. Moreover, Cur-MM-ISG showed a longer retention time on the corneal surface when compared to Cur-MMs using the fluorescein sodium labeling method. These findings indicate that biocompatible Cur-MM-ISG has great potential in ophthalmic drug therapy.

Effect of different edible coatings on biochemical quality and shelf life of apricots (Prunus armenica L. cv Canino)

As apricots have limited marketability due to their high degree of perishability that usually leads to extensive postharvest losses, this study determined the effect of different edible coatings on the quality, enzyme activity and shelf life of apricots. Apricots were dipped in different solutions of alginate, chitosan or gellan gum then stored at 4 °C and 80% ± 2% relative humidity for 15 days. Uncoated fruits were similarly stored as controls. Results revealed that the application of edible coatings reduced a range of degradative changes in the fruits. There were significant differences in a number of biochemical characteristics [pH, titratable acidity (TA), total soluble solids (TSS) and vitamin C], external color, carotenoids, weight loss and firmness when treated samples were compared to control samples. All coatings were effective in inhibiting oxidative enzymes, with significant reductions observed in peroxidase (POD) and polyphenol oxidase (PPO) activities. Specifically, alginate (AL) 1%, chitosan (CH) 1% and gellan gum (GE) 1% demonstrated superiority in inhibiting enzyme activity. Therefore, coating apricots with alginate, chitosan and gellan gum can be considered a useful strategy for minimizing deterioration, maintaining quality and improving the shelf life of apricots under the storage temperature of 4 °C.

Evaluation of Cartilage Regeneration in Gellan Gum/agar Blended Hydrogel with Improved Injectability

Gellan gum is known to be one of the biocompatible materials that resemble living tissues, continuously delivering stem cells or general cells, and filling voids in the wound. In spite of the many advantages of gellan gum, it has difficulty in the application by inserting the scaffolds into the body. In order to generalize gellan gum for medical purpose, it is necessary to increase the injectability of gellan gum. In this study, gellan gum solutions with 0.2, 0.4, 0.6, 0.8 wt% of agar were prepared. The obtained hydrogels were tested for rheological properties and chondrocytes adhesion, morphology and proliferation. Results showed that the addition of agar, in the starting GG solution, allows extruding the material producing micro-porous scaffolds. The biological evaluation demonstrated that the adhesion and proliferation of chondrocytes increase with the presence of agar in the final structure. The solutions composed of GG and agar represent an efficient, fast and high reproducible methodology with the potential to be used as an injectable hydrogel for cartilage regeneration purposes.

Chitosan content modulates durability and structural homogeneity of chitosan-gellan gum assemblies.

Here we report a new and straightforward method to yield durable polyelectrolyte complexes (hydrogel PECs) from gellan gum (GG) and chitosan (CS) assemblies, without metallic and covalent crosslinking agents, commonly used to produce GG and CS-based hydrogels, respectively. This new approach overcomes challenges of obtaining stable and durable GG-based hydrogels with structural homogeneity, avoiding precipitation and aqueous instability, typical of PEC-based materials. PECs are created by blending CS:GG solutions (at 60 °C) with GG:CS weight ratios between 80:20 to 40:60. X-ray photoelectron spectroscopy (XPS) analysis shows that CS-GG chains are interacting by electrostatic and intermolecular forces, conferring a high degree of association to the washed PECs, characteristic of self-assembling of polymer chains. The CS:GG weight ratio can be tuned to improve polyelectrolyte complex (PEC) high porosity, stability, porous homogeneity, and degradation rate. Physical and thermosensitive CS/GG-based hydrogels can have advantages over conventional materials produced by chemical processes.

Large amplitude oscillatory shear behavior and gelation procedure of high and low acyl gellan gum in aqueous solution

The rheological properties of gellan fluid gels were investigated using large amplitude oscillatory shear (LAOS) technique in both linear and non-linear viscoelastic regimes, with consideration of high acyl (HA)/low acyl (LA) gellan ratio and Ca2+ concentration. The Lissajous curves and Chebyshev coefficients were used to analyze the LAOS data and successfully provided visual and quantitative representation of microstructural differences between HA and LA gellan gum, respectively. Temperature sweep measurements were performed to monitor the gelation procedure of gellan gum solution. The results show that HA gellan gum forms softer but more stable gels than LA gellan gum, especially at high temperature. And a synergistic interaction between HA and LA gellan gum may exist in the presence of abundant Ca2+ ions. The abovementioned study can allow a better understanding of structural characteristic of gellan gum and provide a practical approach to rheological assessment that facilitates the processing and diversified application of mixed gellan gum.