Konjac Glucomannan Hydrogel Research Articles

Impact of lecithin on the lubrication properties of konjac glucomannan gels

The effects of lecithin addition on the properties of konjac glucomannan (KGM) hydrogels prepared by controlled heating were investigated. Weak hydrogels were formed at 1 % KGM, which contained relatively thick strands. The shear viscosity and shear modulus of the hydrogels increased with increasing KGM concentration. The pure KGM hydrogels exhibited relatively poor boundary lubrication at all polysaccharide concentrations studied. The inclusion of lecithin (0.001 % to 0.20 %) in the KGM hydrogels appreciably altered their rheological properties, which could be modulated by varying the lecithin/KGM ratio. Microstructural analysis showed that lecithin caused a substantial restructuring of the strands in the hydrogel network. Lecithin was also found to be a highly effective lubricant in the KGM hydrogels. Incorporation of trace amounts of lecithin led to a significant improvement in the lubricating properties of the KGM hydrogels, especially boundary lubrication. Fourier transform infrared (FTIR) and differential canning calorimetry (DSC) analyses provided information about the molecular interactions between the lecithin and KGM molecules. The ability of lecithin to increase the lubricating performance of the KGM hydrogels was mainly attributed to the adsorption of phospholipid-biopolymer complexes onto solid surfaces, which reduced the friction between them.

Improved physicochemical properties of bigels produced with ethyl cellulose-based oleogel and moderately deacetylated konjac glucomannan hydrogel

The ideal physicochemical properties of bigels are important for food applications. Therefore, a new bigel was prepared based on mixed beef tallow and soybean oil oleogel and deacetylated konjac glucomannan (KGM) hydrogel. The effect of the deacetylation degree of KGM on the physicochemical properties and microstructure of bigels was studied. The bigel containing moderate deacetylation degree of KGM had better rheological properties and hardness (319.84 g) than that with low and high deacetylation degrees of KGM. The interactions among the bigel components were analyzed by Fourier transform infrared spectroscopy and molecular dynamics simulation, indicating that the formation of the bigels was dominated by electrostatic interactions. Overall, the bigels containing moderate deacetylation degree of KGM had better physical properties, which may provide a theoretical foundation to develop bigels with low cholesterol, trans and saturated fats levels to replace traditional solid fats in food industry.

Konjac Glucomannan hydrogel loaded with UIO-66 and silver: Antibacterial efficacy and dye adsorption

A composite hydrogel, consisting of Konjac Glucomannan (KGM), UIO-66, and AgCl nanoparticles, was developed. This KGM/UIO-66/AgCl hydrogel combines the biocompatibility of KGM, the large specific surface area and dye adsorption capacity of UIO-66, as well as the antibacterial properties of AgCl nanoparticles. The KGM/UIO-66/AgCl hydrogel effectively inhibited the growth of S. aureus, not only prevented the formation of biofilms but also eradicated already formed biofilms, showing outstanding biocompatibility to reduce the cell turbidity caused by bacterial growth. Additionally, the KGM/UIO-66/AgCl hydrogel demonstrated efficient absorption of various dyes, indicating its potential for the treatment of dye wastewater in an antibacterial setting.

Rapidly degradable konjac glucomannan hydrogels cross-linked with olsalazine for colonic drug release.

Polysaccharide hydrogel is one of the most important materials for the colon target drug release system. However, the degradation time of polysaccharide hydrogel is much longer than the retention time in the colon. The drugs are expelled from the body before being released. In order to match the degradation of drug carriers and their retention time in the colon, a rapidly degradable konjac glucomannan (KGM) hydrogel was designed for colon target drug release. A crosslinker containing azo bond, olsalazine, was used to prepare the rapidly degradable KGM hydrogel. The degradation and drug release of the hydrogels with different crosslinking densities in the normal buffer and the human fecal medium were studied to evaluate the efficiency of colon drug release. More than 50% of the KGM hydrogel by weight was degraded and more than 60% of the 5-fluorouracil (5-Fu) was released within 48h in 5% w/v human fecal medium. The drug was released more rapidly in a simulated colon environment than in a normal buffer. Furthermore, the drug release was controlled by the degradation of the hydrogel. The KGM hydrogel containing azo crosslinker has great potential for colon drug release.

Konjac glucomannan photocrosslinked hydrogels for in vitro 3D cell culture

Konjac glucomannan (KGM) is an attractive naturally-derived polysaccharide commercially available for use in food industry, but with limited application in tissue engineering (TE) as a standalone polymer. We successfully purified and chemically modified KGM, developing innovative covalently crosslinked, fast-forming and degradable KGM hydrogels with tunable mechanical properties for 3D cell culture. Human dermal fibroblasts embedded in KGM matrices remained viable and metabolically active, supporting its good biocompatibility. We further innovated by grafting a bioactive peptide to KGM backbone applying two different chemical approaches, one of them culminating in the synthesis of a novel pH-responsive KGM derivative. Cells embedded in biofunctionalized KGM hydrogels were able to adhere, spread and establish cell-to-cell interactions, encouraging the formation of a cellular network. This work reports different chemical approaches for targeting the fabrication of bioactive KGM-derived hydrogels for 3D cell culture and compares the biological performance of obtained KGM's covalent and semi-interpenetrating polymer networks (SIPN). These results will pave the way for further exploitation of KGM in TE, where it has been commonly applied as blended scaffold formulations rather than as stable extracellular matrix (ECM)-mimicking materials.

Studies on stabilized mechanism of high internal phase Pickering emulsions from the collaboration of low dose konjac glucomannan and myofibrillar protein

In this study, the effects of different concentrations (0%, 0.25%, 0.5%, 1%, 1.5%, w/v) of konjac glucomannan (KGM) on the structure and interfacial adsorption of myofibrillar protein (MP) and the mechanism of co-emulsification of high internal phase Pickering emulsions (Pickering HIPEs) by KGM and MP were investigated. The results showed that for interfacial MPs, KGM addition promoted MP structure unfolding and improved MP wettability with a three-phase contact angle from 73.69° (control) to 89.41° (0.5% KGM), thereby lowering the energy barriers to MP penetrating and rearranging at the interface. Furthermore, the adsorption kinetics and protein adsorption percentage (AP%) indicated that KGM (≤1%) facilitated the adsorption of MP from the aqueous phase to the oil-water interface. For MP in the aqueous phase, KGM induced a denser MP network structure by promoting “concentrated” MP and connecting MP through hydrogen bonding, which formed a stronger spatial site resistance and hindered oil droplet aggregation. KGM (≤1%, especially 0.5%) resulted in reduced droplet size, relaxation time (T2), lipid oxidation, and improved storage stability and energy storage modulus of Pickering HIPEs. However, the competitive adsorption of KGM (>1%) significantly decreased the interface MP, and the formation of continuous KGM hydrogel formed an unaggregated MP network structure, decreasing the emulsion performance further. Overall, KGM could modulate the physical properties of MP-stabilized Pickering HIPEs by altering the interfacial adsorption and network structure.

Enhanced mechanical property and freeze-thaw stability of alkali-induced heat-set konjac glucomannan hydrogel through anchoring interface effects of carboxylated cellulose nanocrystals

The alkali-induced heat-set konjac glucomannan (KGM) hydrogels have drawn increasing attention due to their high absorbency and thermal irreversibility ability, but pure KGM hydrogels generally have defects of low strength and high syneresis rate. Cellulose nanocrystals and their derivatives, which have a very high specific surface area, good biocompatibility, biodegradability, and low toxicity, are promising candidates to solve this challenge. In this work, we propose the use of carboxylated cellulose nanocrystals (C–CNCs) as nanofillers for the strengthening of KGM hydrogels. The effects of the C–CNCs content on the microstructure and physical properties of the KGM hydrogels and their possible mechanism were investigated. The compressive test results indicate great improvement in the mechanical properties upon the addition of the C–CNCs for the KGM hydrogel and reached a maximum value at 20% loading. The microstructure analyses of the KGM hydrogel revealed that the well-distributed C–CNCs can act as a physical cross-linker to connect the neighboring KGM chains to strengthen the resultant hydrogel, based on their strong interactions, including hydrogen bonding and chain entanglements. Moreover, adding 20% C–CNCs can significantly decrease the syneresis after five repeated freeze-thaw cycles of the KGM hydrogels. Compared to pure KGM hydrogels, KGM/C–CNCs nanocomposite hydrogels demonstrated higher water-binding capability based on Low-field nuclear magnetic resonance. These findings indicate that C–CNCs are considered anchors for KGM chains as well as reinforcement fillers in the polymer matrix, which contributes significantly to the mechanical property of the nanocomposite. Therefore, C–CNCs were a promising material to be applied for modulating the mechanical and freeze-thaw stability properties of the polysaccharide-based hydrogel in food and biomedical applications.

Freeze-thaw stability of konjac glucomannan hydrogels supplemented with natural tapioca/corn starch

The poor freeze-thaw stability of konjac glucomannan (KG) hydrogel will greatly affect its application in the frozen prepared foods. In this study, the filling effects of natural tapioca starch (TS) and corn starch (CS) on the properties of freeze-thaw KG hydrogel were evaluated. The addition of starches significantly improved the gel strength and water holding capacity and inhibited the freeze-induced syneresis of composite hydrogels, where CS is superior to TS. These beneficial effects could be the results of concurrent effects of the decrease of frequency dependence/freezing point, the formation of dense microstructure and the reinforced hydrogen bonds and hydrophobic interactions of composite hydrogels. The foregoing results suggested the potential feasibility of low-cost natural starches to improve the textural properties and freeze-thaw stability of KG hydrogels.

Preparation and Application of Double Network Interpenetrating Colon Targeting Hydrogel Based on Konjac Glucomannan and N-Isopropylacrylamide.

Konjac glucomannan (KGM) can be degraded by colon-specific enzymes in the colonic environment, making it one of the materials for treating colonic diseases, which has attracted more and more attention. However, during drug administration, especially in the gastric environment and due to its easy swelling, the structure of KGM is usually destroyed and the drug is released, thereby reducing the bioavailability of the drug. To solve this problem, the easy swelling and drug release properties of KGM hydrogels are avoided by creating interpenetrating polymer network hydrogels. In this study, N-isopropylacrylamide (NIPAM) is first formed into a hydrogel framework under the action of a cross-linking agent to stabilize the gel shape before the gel is heated under alkaline conditions to make KGM molecules wrap around the NIPAM framework. The structure of the IPN(KGM/NIPAM) gel was confirmed using Fourier transform infrared spectroscopy (FT-IR) and x-ray diffractometer (XRD). In the stomach and small intestine, it was found that the release rate and swelling rate of the gel were 30% and 100%, which were lower than 60% and 180% of KGM gel. The experimental results showed that this double network hydrogel has a good colon-directed release profile and fine drug carrier ability. This provides a new idea for the development of konjac glucomannan colon-targeting hydrogel.

Experimental preparation and mechanism analysis of a neotype composite gel for coal spontaneous combustion prevention and coal-fire extinguishment

Spontaneous coal combustion (SCC) seriously threatens the safety production of coal mines. A neoteric irreversibly thermo-sensitive composite gel based on konjac glucomannan (KGM) and expandable graphite (EG) was elaborately synthesized for preventing SCC disasters and coal fires. Firstly, the primary properties such as the gelation time, the water retention rate, the rheological law, the microstructure characteristics, and the thermal decomposition properties concerning the composite gel were explored systematically. The results demonstrated that composite gel is non-Newton fluids with excellent self-repairing capability, and the gel exhibited controllable gelation properties, favorable seepage capacity, and strong water retention characteristics. Besides, SEM observations and thermogravimetry analysis suggested that the interspersed network structures of KGM embedded by EG exhibits higher denseness, greater physical strength, superior structural stability, and more remarkable thermal stability, and EG was closely adhered to the KGM hydrogel network but distributed inhomogeneously. Furthermore, the high-temperature pyrolysis tests showed that the decomposition rate accelerated to 0.234 %/°C and 0.225 %/°C at the temperature of 266.5 °C and 275.1 °C, respectively. Meanwhile, both the low-temperature oxidation experiments and fire-extinguishing experiments showed a favorable inhibition effect of the composite KGM@EG gel, indicating that KGM@EG gel is applicable to inhibit the high-temperature pyrolysis rate of coal, and could effectively inhibit the heat buildup, O2 consumption, and CO formation over the oxidation and combustion process of coal, which would lower the possibility of SCC and coal fires. Therefore, KGM@EG composite gel can play an efficient SCC-preventing and fire-extinguishing role in the safety production of coal mines. Finally, the underlying mechanism for SCC preventing and fire-extinguishing concerning the thermo-sensitive gel was revealed and proposed.

Hydrogel Derived from Glucomannan-Chitosan to Improve the Survival of Lactobacillus acidophilus FNCC 0051 in Simulated Gastrointestinal Fluid.

The probiotic encapsulating hydrogel derived from porang (Amorphophallus oncophyllus) glucomannan and chitosan was investigated with regard to its encapsulation efficiency, physical properties, prebiotic activity, and survival under simulated gastrointestinal conditions. The hydrogel's encapsulation efficiency was improved by varying the number of the Lactobacillus acidophilus FNCC 0051, which also served to increase the diameter (2-3 mm), polydispersity index (1.23-1.65), positive zeta potential, whiteness, and brightness of the hydrogel. Moreover, the hydrogel's prebiotic activity score was higher than that of inulin after 24 h of incubation, reflecting its role as a cell encapsulant, particularly when it comes to maintaining cells during exposure to simulated gastrointestinal fluid. The cell viability increased from 86% to 100% when immersed in intestinal juice, which is comparable to the increase achieved using alginate and konjac glucomannan hydrogels. Future animal studies are required to determine the cell viability in actual gastrointestinal conditions and assess the health effects of the hydrogel.

Effects of L-lysine and L-arginine on the structure and gel properties of konjac glucomannan

To explore greener modifier of konjac glucomannan, a new type of thermal irreversible gel using konjac glucomannan (KGM) and basic amino acids (l-lysine, and l-arginine) was prepared in the present study. The effects of different concentrations (1%, 2%, 3%, 4%, and 5%) of these two basic amino acids on the structure and properties of KGM hydrogels were mainly studied. The results showed that there was a better texture characteristic of composite gel as the concentration of amino acids was above 4%. Besides, with the increase in amino acid concentrations, the pore size of composite gel was denser and the syneresis of composite gel was more obvious, respectively. The rheological results indicated that the storage modulus (G′) was influenced by the concentration of amino acids and temperature. It was found that the two basic amino acids removed the acetyl group of KGM molecule and changed the original crystalline domain of KGM as evidenced by FT-IR and X-ray diffraction (XRD) analysis. Furthermore, compared to l-lysine, l-arginine could exert a greater effect on the KGM gel. In conclusion, the two basic amino acids (l-lysine, and l-arginine) could remarkedly improve the structure and properties of natural KGM and could be used as modifiers of the KGM hydrosol.

Ultrasound Viscoelastic Properties of Biomass Polysaccharide Hydrogels as Evaluated by Rheometer Equipped with Sono-Device.

A viscoelastic rheometer was equipped with a sono-device and a water bath to enable measurement of storage moduli G′ and loss moduli G″ of biomass polysaccharide hydrogels such as Kanten agarose, κ-carrageenan, and konjac glucomannan under ultrasound (US) exposure. The action of low power of 43 kHz US on their hydrogels significantly decreased G′ of Kanten agarose and carrageenan after a few seconds of US exposure 0.1% strain. When US with 20 W output power was exposed under mechanical strain at 0.1%, lower values were obtained cyclically for 3 min US intervals. The values then reverted to the original moduli values when US was stopped in cases of Kanten agarose and carrageenan hydrogels. As G″ values were increased during US operation, the anhydro-L-galactose segments in their hydrogels were unable to relax the external US forces within the gel sufficiently, thereby leading to gel structure collapse at a higher strain percentage. These results suggest that US exposure induced deformational change in the hydrogel structure formed by hydrogen-bonded cross-links. However, US deformation was less in the case of deacetylated cross-linkage in konjac glucomannan hydrogel.

Construction of Konjac Glucomannan/Oxidized Hyaluronic Acid Hydrogels for Controlled Drug Release.

Konjac glucomannan (KGM) hydrogel has favorable gel-forming abilities, but its insufficient swelling capacity and poor control release characteristics limit its application. Therefore, in this study, oxidized hyaluronic acid (OHA) was used to improve the properties of KGM hydrogel. The influence of OHA on the structure and properties of KGM hydrogels was evaluated. The results show that the swelling capacity and rheological properties of the composite hydrogels increased with OHA concentration, which might be attributed to the hydrogen bond between the KGM and OHA, resulting in a compact three-dimensional gel network structure. Furthermore, epigallocatechin gallate (EGCG) was efficiently loaded into the KGM/OHA composite hydrogels and liberated in a sustained pattern. The cumulative EGCG release rate of the KGM/OHA hydrogels was enhanced by the increasing addition of OHA. The results show that the release rate of composite hydrogel can be controlled by the content of OHA. These results suggest that OHA has the potential to improve the properties and control release characteristics of KGM hydrogels.

Konjac glucomannan hydrogel dressing and its combination with Chinese medicine for the wound treatment

A biocompatible konjac glucomannan hydrogel dressing is developed and its combination with arnebia root oil displays improved wound healing in acute and chronic wound models.

Konjac Glucomannan (KGM), Deacetylated KGM (Da-KGM), and Degraded KGM Derivatives: A Special Focus on Colloidal Nutrition.

Konjac flour, mainly obtained and purified from the tubers ofAmorphophallus konjac C. Koch, yields a high molecular weight (Mw) and viscous hydrocolloidal polysaccharide: konjac glucomannan (KGM). KGM has been widely applied in the food industry as a thickening and gelation agent as a result of its unique colloidal properties of effective viscosity enhancement and thermal-irreversible gelling. This review first narrates the typical commercial KGM source species, the industrial production, and the purification process of KGM flour. The structural information on native KGM, gelation mechanisms of alkali-induced deacetylated KGM (Da-KGM) hydrogel, progress on degraded KGM derivatives, cryoprotection effect, and colloidal nutrition are highlighted. Finally, the regulatory requirements of konjac flour and KGM among different countries are briefly introduced. The fine structure and physicochemical properties of KGM can be regulated in a great range via the deacetylation or degradation reaction. Here, the relationship between the physicochemical properties, such as viscosity, solubility, gelation, and nutritional effects, of native KGM, Da-KGM, and degraded KGM derivatives was preliminary established, which would provide theoretical guidance for designing KGM-based products with certain nutritional needs.

Ionic liquid functionalized non-releasing antibacterial hydrogel dressing coupled with electrical stimulation for the promotion of diabetic wound healing

Chronic wounds are more difficult to be cured than the general wounds, particularly for the wounds of diabetic patients. It also increases the risk of bacterial infections and may cause other serious complications. Electrical stimulation (ES) can promote the healing of wounds efficiently. However, single electrode-based ES strategy is difficult to cover the entire part of the wounded area that may cause unsatisfactory treatment efficiency. We herein reported a multifunctional and conductive hydrogel dressing developed based on the polymerized ionic liquid and konjac glucomannan (KGM). It was found that this newly developed hydrogel dressing not only possesses excellent mechanical properties and biocompatibility but also provides a durable and efficient sterilization effect without releasing antibacterial factors. With the enhancement of current electrical stimulation by using this hydrogel dressing, the migration and proliferation of fibroblast cells and the treatment effect towards diabetic skin wounds were significantly improved. The polymerized and ionic liquid functionalized KGM hydrogel dressing coupled with ES may be able to provide a novel strategy for treating chronic wounds efficiently.

Magnetic hydrogel for the rapid elimination of environmental harmful ions

We have newly devised konjac glucomannan hydrogel pellets containing micrometer-sized iron particles and hydrotalcite powder [1], by which we can efficiently remove environmental harmful ions such as selenium, boron, fluorine and arsenic. Glucomannan hydrogel forms three-dimensional network which can stably immobilize these materials Figure 1. Iron Magnetic hydrogel (Japanese Patent 6667880 (2019)).

Konjac glucomannan/kappa carrageenan interpenetrating network hydrogels with enhanced mechanical strength and excellent self-healing capability

Konjac glucomannan (KGM) hydrogels have attracted considerable interest in many fields, such as drug delivery, tissue engineering, bio-medicine, and food processing, due to their good biocompatibility, biodegradability, gelation performance and security. However, KGM hydrogels prepared by traditional methods often exhibit poor mechanical properties, severely limiting their practical applications. To obtain hydrogels of excellent mechanical performance, a simple one-step method was developed. Through this method, KGM/kappa-carrageenan (KC) hydrogels of interpenetrating network (IPN) structure were prepared, where the chemical gel network was constructed via reaction between the KGM and borax and the physical network was built by introducing a KC component. Besides, the –OSO3− groups on the KC chains will also interact with the hydroxyl groups on the KGM chains to form hydrogen bonds, effectively binding the two networks into a whole. We find that the tensile strength of the obtained IPN hydrogels can reach to 100.2 kPa. Since the second physical network structure is temperature sensitive and recoverable, the hydrogels obtained by our method are of excellent self-healing performance. Our results showed that the mechanical strength of the self-healed hydrogels can recover by 96.7% after heat treating at 60 °C for 30 min.

Insight into the mechanism of physicochemical influence by three polysaccharides on myofibrillar protein gelation

In this study, the effect and mechanism of myofibrillar protein (MP) gelation influenced by the hydration characteristic of three polysaccharides were studied through puncture test, paraffin section, SEM and Raman spectroscopy. The gel strength and water holding capability reflect that MP gelation only significantly improves until modified starch (MS) addition beyond 1.0%. The MS granule improves MP gel property through simply physical swelling effect. At gelatinization temperature, MS absorbs the moisture nearby to compress the MP three-dimensional networks, but the swelling effect is limited. The insoluble dietary fiber (IDF) improves MP gelation property through moisture stability. The IDF addition could lessen the appearance of moisture channel in MP gel networks and promote the interaction of hydrophobic groups. The MP gelation with 2.0% IDF addition has the highest gel strength (279 g) and water holding capability (91.87%). The konjac glucomannan (KG) (>1.0%) could degrade gel property of MP gelation through interpenetrate structure, because the KG hydrogel hinders the aggregation of the MP gel networks. In conclusion, the IDF, which has strong water-holding capability at room temperature and distribute individually, is the best polysaccharides-based fat replacement in low-fat restructured products.