Carboxymethyl Konjac Glucomannan Research Articles

Fabrication, characterization and in vitro controlled-releasing of naringin nano-particles encapsulated by chitosan-carboxymethyl konjac glucomannan

Naringin (NR) is a prominent citrus bioflavonoid, but the application is greatly limited by its low bioavailability. To solve this problem, NR was encapsulated in carboxymethyl konjac glucomannan (CKGM) and chitosan (CS) to form core-shell nanoparticles (CS/CKGM-NR NPs). The physicochemical properties of CS/CKGM-NR NPs with ideal encapsulation efficiency of 82.70 ± 0.30% were characterized by fourier transform infrared spectroscopy and differential scanning calorimetry. The morphology and core-shell structure of CS/CKGM-NR NPs were observed to be successful formation (diameter 700 nm, +35 mV). Moreover, the releasing behavior of NR was evaluated in In Vitro digestion mode. The underlying mechanism indicated that carboxyl groups of CKGM were cross-linked with ammonium ion of CS by electrostatic interaction. Moreover, the releasing efficiency of NR in simulated gastric fluid (SGF, 20.62 ± 0.59%), simulated intestinal fluid (SIF, 17.08 ± 0.01%) and simulated colon fluid (SCF, 18.82 ± 0.61%) were greatly lowered compared with that of naked NR (52.70 ± 0.01% in SGF, 46.42 ± 3.30% in SIF, 69.35 ± 12.63% in SCF). The findings implied that CS/CKGM-NR NPs were created in core-shell structure with controlled-releasing effect. This study provided new insight into the fabrication of CS/CKGM-NR NPs that could be developed as a potential nano-delivery with controlled-releasing effect.

Antibacterial activity of lysozyme after association with carboxymethyl konjac glucomannan

The unique high isoelectric point of lysozyme (LYZ) restricts its application in composite antibacterial coating due to the unfavorable liability to electrostatic interaction with other components. In this work, the antibacterial activity of a dispersible LYZ–carboxymethyl konjac glucomannan (CMKGM) polyelectrolyte complex was evaluated. Kinetic analysis revealed that, compared with free LYZ, the complexed enzyme exhibited decreased affinity (Km) but markedly increased Vmax against Micrococcus lysodeikticus, and QCM and dynamic light scattering analysis confirmed that the complex could bind with the substrate but in a much lower ratio. The complexation with CMKGM did not alter the antibacterial spectrum of LYZ, and the complex exerted antibacterial function by delaying the logarithmic growth phase and impairing the cell integrity of Staphylococcus aureus. Since the LYZ–CMKGM complex is dispersible in water and could be assembled easily, it has great potential as an edible coating in food preservation.

Co-delivery system based on multilayer structural nanoparticles for programmed sequential release of fucoxanthin and curcumin

Multilayer structural nanoparticles (MSNPs) fabricated by gliadin (Gli), carboxymethyl konjac glucomannan (CMK) and chitosan hydrochloride (CHC) were used to co-encapsulate fucoxanthin (FUC) and curcumin (Cur), and the effect of CHC level on the physiochemical properties of MSNPs (FUC-Gli-CMK-Cur-CHC) was evaluated. The prepared FUC-Gli-CMK-Cur-CHC had a particle size of about 628.1 nm and showed a spherical shape with high ζ potential (+27.1 mV) and maximal encapsulation efficiency of FUC (96.3%) and Cur (72.8%). Lyophilized FUC-Gli-CMK-Cur-CHC exhibited excellent water redispersibility after the addition of CHC. Furthermore, the physical stability, storage stability and thermal stability of MSNPs were dramatically improved by CHC coating. FUC-Gli-CMK-Cur-CHC were shown to be effective at retarding the photo- and thermal-degradation of the encapsulated FUC and Cur. In addition, in vitro release and in vivo gastrointestinal distribution studies demonstrated that the prepared MSNPs exhibited programmed sequential release properties, which enabled the delivery of Cur and FUC in the small intestine and colon, respectively. This research provides new insights for MSNPs in constructing co-delivery systems and programmed sequential release of active substances.

A pH-sensitive hydrogel based on carboxymethylated konjac glucomannan crosslinked by sodium trimetaphosphate: Synthesis, characterization, swelling behavior and controlled drug release

The pH-sensitive hydrogel consisting of carboxymethylated konjac glucomannan (CMKGM) and sodium trimetaphosphate (STMP) was prepared for a potential intestinal targeted delivery system. Both the CMKGM and the CMKGM hydrogel were characterized by FT-IR spectra, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The Congo red and atomic force microscope (AFM) results showed a coil-to-helix transition of CMKGM in alkaline conditions with the degree of substitution (DS) increased from 0.20 to 0.49. Rheological measurements indicated that the DS and the STMP content collectively influence the mechanical stiffness and swelling properties of the obtained hydrogels. In addition, the swelling behavior of the hydrogels revealed that they were sensitive to pH value changes and were following a Korsmeyer-Peppas gastrointestinal release behavior, indicating that the release was controlled by non-Fickian diffusion. Furthermore, all the results suggested that the prepared pH-sensitive hydrogel may serve as a potential biomaterial for the intestine-targeted delivery system.

Association between Lysozyme and Carboxymethyl Konjac Glucomannan to Produce Dispersible Coacervates

Association between Lysozyme and Carboxymethyl Konjac Glucomannan to Produce Dispersible Coacervates

Fabrication, characterization of carboxymethyl konjac glucomannan/ovalbumin-naringin nanoparticles with improving in vitro bioaccessibility.

Naringin is potential functional and therapeutic ingredient, has low bioavailability because of poor aqueous solubility. In this study, an ovalbumin (OVA)-carboxymethyl konjac glucomannan (CKGM) nano-delivery system was developed to enhance the bioavailability of naringin. The effects of proportion (OVA: CKGM), pH and naringin concentration were studied on the formation, encapsulation efficiency (EE) and bioaccessibility of OVA/CKGM-Naringin nanoparticles (OVA/CKGM-Naringin NPs). Its morphology and size were viewed by Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). The cross-linkage between OVA and CKGM was verified by Fourier Transform Infrared Spectroscopy (FTIR) and Fluorescence Intensity analysis. The size of OVA/CKGM-Naringin NPs were 463.83±18.50nm (Polydispersity Index-PDI, 0.42±0.05). It indicated that 2:1 of OVA: CKGM, pH 3 and 7mg/mL of naringin concentration were optimized processing parameters of OVA/CKGM-Naringin NPs with EE (97.90±2.97%) and remarkably improved bioaccessibility (85.01±2.52%). The OVA/CKGM-Naringin NPs was energy efficiently prepared and verified as an ideal carrier of naringin.

Effect of carboxymethyl konjac glucomannan coating on the stability and colon-targeted delivery performance of fucoxanthin-loaded gliadin nanoparticles

Fucoxanthin (FUC) is a hydrophobic carotenoid that has a protective effect on the colon. To exert the beneficial effects of FUC in the colon and expand its application in functional food, FUC was encapsulated in carboxymethyl konjac glucomannan (CMKGM)-coated gliadin nanoparticles (Gli-CMKGM NPs) in this paper. Gli-CMKGM NPs were prepared at pH 5.0 with Gli/CMKGM mass ratio of 1:1. The formation of Gli-CMKGM NPs was associated with hydrogen bonding, hydrophobic interactions and electrostatic attractions. Additionally, Gli-CMKGM NPs exhibited good stability to pH, salt, heating and storage. The results showed that FUC had been successfully encapsulated in Gli-CMKGM NPs, and the encapsulation efficiency of FUC-Gli-CMKGM NPs was significantly higher than that of uncoated FUC-Gli NPs. FUC-Gli-CMKGM NPs had a nano-spherical structure, and embedded FUC in Gli-CMKGM NPs improved their stabilities to photodegradation and thermal degradation. Furthermore, in vitro release and in vivo organ distribution studies showed that FUC-Gli-CMKGM NPs had an excellent colon targeting function. Overall, our findings illustrated the promise of CMKGM-coated Gli NPs for constructing targeted delivery systems for FUC.

Effect of carboxymethyl konjac glucomannan coating on curcumin-loaded multilayered emulsion: stability evaluation

The stability against various environmental stresses of the curcumin-loaded secondary and tertiary emulsions that was emulsified by whey protein isolate (WPI) and coated by chitosan (CHI), carboxymethyl konjac glucomannan (CMKGM), or their combination through layer-by-layer assembly was investigated. Generally, the multilayered emulsions were destabilized in high NaCl concentrations or medium pH that could interrupt the electrostatic interaction between the three polyelectrolytes or deprotonate CHI, indicating that electrostatic interaction played an important role in the stability of emulsions. Compared with the primary emulsion that was solely stabilized by WPI, extra coating with CHI and CMKGM generally increased the stability of the emulsion against repeated freezing-thawing, improved the retention of curcumin against heating, UV irradiation, and long-term storage, and the effects were more remarkable in the tertiary emulsion with CMKGM locating in the outmost layer. Since CMKGM has shown the colon-targeted delivery potency, the multilayered emulsions assembled by layer-by-layer deposition, especially the tertiary emulsion, could be used as an effective carrier for the targeted delivery of curcumin.

Formation of composite hydrogel of carboxymethyl konjac glucomannan/gelatin for sustained release of EGCG

Development of functional bioinspired hydrogels that have good releases control character is necessary for the application of these materials in biomedical engineering. Herein, we report a composite hydrogel prepared from several biocompatible carboxymethyl konjac glucomannan (CKGM)/gelatin (G)/tannic acid (TA) functional nano-hydroxyapatite (TA@n-HA), which has good biodegradability and pH sensitivity. The mechanism of interaction between hydrogels was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, Scanning electron microscopy and Thermogravimetric analysis. The physico-chemical properties of CKGM/G hydrogels have been significantly improved through the incorporation of TA@n-HA within the matrix. Studies in the sustained release of epigallocatechin gallate (EGCG) demonstrated that the TA@n-HA/CKGM/G hydrogels exhibit not only better pH sensitive properties, but also enhanced biocompatibility and encapsulation in comparison to the matrix devoid of TA@n-HA. Consequently, TA@n-HA/CKGM/G hydrogels using EGCG as a drug release model show the potential for drug delivery.

Thermostable physically crosslinked cryogel from carboxymethylated konjac glucomannan fabricated by freeze-thawing

Physically crosslinked cryogels of carboxymethylated konjac glucomannan (CMKGM) with different molecular weights (Mw, 1.57 × 105–7.33 × 105 Da) and degrees of substitution (DS, 0.19–1.63) were fabricated by using the freeze-thaw technique. The acidification of CMKGM solution at a sufficiently low pH of 1.0 is a prerequisite to produce a cryogel. Both the Mw and DS of CMKGM significantly affected the formation and mechanical strength of the cryogels. A high DS value cannot ensure the formation of the cryogel when the Mw of CMKGM is not sufficiently high. While the cryogel from CMKGM with the highest Mw of 7.33 × 105 Da and lowest DS of 0.19 exhibited the highest gel strength, cryogels could not be effectively formed for CMKGM with a DS beyond 1 and Mw below 2.24 × 105 Da. Furthermore, the gel strength could be enhanced by increasing polysaccharide concentration, freezing time, and the number of freeze-thaw cycles or thawing at a moderate temperature (25 °C). It was demonstrated that the intermolecular multiple hydrogen bonding was the major driving force in the formation of CMKGM cryogels with negligible, if any, participation of crystalline ordered structures. Detailed hydrogen bonding patterns in the gel network were proposed. In acidic cryogels, there existed three types of hydrogen bonds formed by –COOH and –OH groups, whereas in neutral cryogels, two kinds of hydrogen bonding among -COO- and –OH groups were involved. The intermolecular multiple hydrogen bonding endows the physical hydrogels with excellent thermostability.

Construction of carboxymethyl konjac glucomannan/chitosan complex nanogels as potential delivery vehicles for curcumin

Construction of nanoscale delivery systems from natural food biopolymer complexes have attracted increasing interests in the fields of food industries. In this study, novel carboxymethyl konjac glucomannan/ chitosan (CMKGM/CS) nanogels with and without 1-ethyl-3-(3-dimethylaminopropyl) /N-hydroxysuccinimide) (EDC/NHS)-initiated crosslinking were prepared. The physicochemical and structural properties of the CMKGM/CS nanogels and their potential to be a delivery vehicle for curcumin were investigated. Compared to original uncrosslinked nanogels, crosslinking did not alter particle size and morphology but decreased zeta potential of nanogels. Fourier transform infrared spectrum confirmed that the amide linkage was formed between CMKGM and CS, which obviously enhanced the stability of crosslinked nanogels under gastrointestinal conditions. Furthermore, the crosslinked nanogels not only had higher encapsulation efficiency of curcumin but also better sustained release behavior under simulated gastrointestinal conditions. These findings suggested that the crosslinked CMKGM/CS nanogels might be a promising delivery system for nutrients.

Comprehensive physical visualisation of the chain conformation and solution property of carboxymethylated konjac glucomannan: Comparison of charged and uncharged polyelectrolytes

The present work deals with a comprehensive molecular characterization and delineation of solution property of a series of charged and uncharged carboxymethylated konjac glucomannan (CMKGM) with different molecular weights (Mw, 1.57 × 105–7.33 × 105) and degrees of substitution (DS, 0.19–1.63) by using various rheological models and solution scaling theory. CMKGM macromolecules in aqueous solutions are found to adopt semi-flexible chain conformation and show a tendency close to rigid chains with decreasing Mw and increasing DS. For uncharged CMKGM solutions, the Huggins–Kraemer, Heller, Fuoss and Wolf approaches can achieve equally excellent fitting results for the determination of intrinsic viscosity [η], whereas for charged CMKGM solutions, only the Huggins–Kraemer and Wolf plots are valid. In accordance with the physical scaling law, a scaling relationship exists between rheological parameters and concentration c for salt and salt-free aqueous solutions of CMKGM. The relationship of specific viscosity ηsp ~ c[η] and ηsp ~ c ~ Mw is derived for CMKGM in a high ionic strength environment (NaCl 0.15 M) by using the Kulicke-Keniewske approach. The constitutive models of the linear Maxwell model and two kinds of non-linear PTT and Giesekus models have also been applied to quantitatively describe the rheological properties of CMKGM entangled solutions under either dynamic or steady shear flow.

Complex coacervation of carboxymethyl konjac glucomannan and ovalbumin and coacervate characterization

Carboxymethyl konjac glucomannan (CMKGM) is an anionic derivative of konjac glucomannan (KGM). Its coacervation with ovalbumin (OVA) was investigated through turbidity and coacervate yield measurements and the resultant CMKGM-OVA coacervates were characterized as a function of phase separation pH. The results indicated that CMKGM could coacervate with OVA in pHs ranging from 2.0 to 4.5. OVA to CMKGM mass ratios higher than 1:1 led to insoluble coacervates, while lower ratios conferred soluble complexes. NaCl suppressed the interaction between CMKGM and OVA and could resuspend their precipitated coacervates. The interaction between the two polyelectrolytes was not affected in temperatures ranging from 25 °C to 55 °C, but was weakened in higher temperatures. The coacervation increased the thermal stability and induced structural changes in both the polyelectrolytes. Atomic force microscope observation revealed that the CMKGM-OVA coacervates separated in mass ratio 1:1 was not susceptible to aggregation, and quartz crystal microbalance with dissipation analysis demonstrated that OVA exhibited the strongest absorption towards CMKGM in pH 3.0 in multilayer mode. Hence, CMKGM is a promising polyelectrolyte for coacervation with proteins and could be used in the construction of targeted delivery systems through the electrostatic interaction with oppositely charged biopolymers.

A novel glucomannan incorporated functionalized carbon nanotube films: Synthesis, characterization and antimicrobial activity

A novel nanocomposite film was developed by incorporating functionalized carbon nanotube (PCNT) and gallic acid (GA) into carboxymethyl konjac glucomannan (CKGM) and gelatin (GL) matrix. The influences of the PCNT content on the structural, morphological, mechanical, barrier, thermal and antimicrobial properties of CKGM/GL nanocomposite film were discussed. The structure of PCNT@CKGM/GL nanocomposite film was characterized by FT-IR, SEM, and AFM. The crystal structure and thermal ability of the film were generated by XRD and TGA-DTG. The analyses of FT-IR revealed that the amide linkage and strong hydrogen bonding were formed between CKGM, GL, and PCNT. Moreover, the characterization of mechanical properties, moisture barrier, and antimicrobial activities indicated the benefits of adding PCNT into CKGM/GL films. The results suggested that the PCNT@CKGM/GL films exhibited antimicrobial activity against Staphylococcus aureus and Escherichia coli. Therefore, such antimicrobial nanocomposite films have the potential of maintaining the quality and prolong the shelf life of food products.

Novel synthesis of mussel inspired and Fe3+ induced pH-sensitive hydrogels: Adhesion, injectable, shapeable, temperature properties, release behavior and rheological characterization

A novel EGCG-loaded DCKGM-CCKGM-Fe3+hydrogel was prepared by Dopamine–carboxymethyl konjac glucomannan (DCKGM) and an l-Cysteine–carboxymethyl konjac glucomannan (CCKGM) with Fe3+ as a cross-linking agent. Due to the dynamic property of Fe3+-phenolic hydroxyl coordination bond and intermolecular hydrogen bonding, the resultant hydrogel featured injectable, adhesive, temperature and pH-sensitive properties. The mechanisms were characterized using Rheological analysis, Fourier transform infrared spectroscopy, X-ray diffraction patterns, and scanning electron microscopy. Furthermore, the weak alkaline condition (pH 7.4) can trigger the release of EGCG, there was a cumulative release of 54.71 % of the loaded EGCG within 12 h in PBS at pH 1.2. When the pH of PBS was increased to 7.4, the cumulative release of EGCG increased to 68.54 %. Consequently, the EGCG-loaded DCKGM-CCKGM-Fe3+hydrogel (Fe3+Hydrogel) is a good candidate for the carrier for drug delivery. This paper provided a novel way for the preparation of hydrogel.

Carboxymethyl konjac glucomannan mechanically reinforcing gellan gum microspheres for uranium removal

Biosorbents have been a promising adsorbent to remove uranium while their poor mechanical properties prevent them from being widely used in practice. In this study, carboxymethyl konjac glucomannan (CMKGM) was incorporated to gellan gum to form a double-network gel micro spheres (CMKGM/GG-Al) for uranium removal with its mechanical strength fairly being reinforced. The compressive strength of the CMKGM/GG-Al microspheres was about 6 times than that of GG-Ca microspheres we prepared before while the adsorption capacity still be at a better value with the fitting maximum adsorption capacity being of 97.94 mg/g. Its uranium adsorption properties were investigated by considering the influence of pH, the adsorbent dosage, temperature, initial uranium concentration, time and coexisting ions. The adsorption mechanism was also investigated according to the SEM, EDX, FT-IR and XPS data analysis. The isotherm equilibrium data which were best fitted with Langmuir model and the kinetics data which were best fitted with pseudo-second-order model. It was inferred that the adsorption process was mainly the ion-exchange and the coordination with hydroxyl groups on the adsorbent surface and the adsorption process was endothermic and spontaneous. The CMKGM/GG-Al microspheres prepared in this study would be more conducive to practical application for uranium removal.

Characterization of carboxymethylated konjac glucomannan for potential application in colon-targeted delivery

Carboxymethylation is a potential way to extend the application of konjac glucomannan (KGM) in the construction of colon-targeted delivery systems through electrostatic interaction-based techniques. Hence, some related properties of carboxymethylated KGM (CMKGM) were characterized as a function of its degree of substitution (DS). Carboxymethylation decreased the molecular weight and viscoelasticity, increased the thermal stability and water solubility of KGM in a DS-dependent manner, but did not destroy the sensitivity of solution viscosity to temperature variation. The gelation ability of the CMKGMs was greatly weakened and the hardness of their gels was greatly impaired. The CMKGMs carried negative charges with zeta potentials proportional to their DSs, but still maintained similar resistance to proteolytic enzymes and susceptibility to β-mannanase with the native KGM. Hence, the CMKGMs are potential in the construction of colon-targeted and enzyme-triggered delivery systems through layer-by-layer assembly, complex coacervation, and other similar techniques.

Complex coacervation of carboxymethyl konjac glucomannan and chitosan and coacervate characterization

Carboxymethyl konjac glucomannan (CMKGM) shows potential in the construction of colon-targeted delivery systems through electrostatic interaction-based techniques. Its coacervation with chitosan (CHI) was investigated as a function of degree of substitution (DS). CMKGMs displayed the same optimum coacervation conditions of pH 6.5 and mass ratio 1:1 with CHI, but the coacervate yield was positively related to their DS. The coacervation was weakened by the presence of NaCl, but was not affected in temperatures 25–75 °C and total biopolymer concentrations 0.05–0.15% (w/v). Both electrostatic interaction and hydrogen bonding were involved in the coacervation and a higher DS contributed a denser network structure, a smaller particle size, and greater elasticity. The coacervates maintained their structures in simulated gastrointestinal fluids, but could be degraded by the β-mannanase in simulated colonic fluid. Hence, CMKGMs could be used in colon-targeted and enzyme-triggered delivery systems and the delivery performance could be tailored by varying their DS.

Adsorption of phosphorus from slaughterhouse wastewater by carboxymethyl konjac glucomannan loaded with lanthanum

Phosphorus removal was an important measure in the control of eutrophication of water environment. In this study, a novel phosphorus removal adsorbent of lanthanum-loaded carboxymethyl konjac glucomannan microspheres (CMKGM-La) was successfully prepared by the method of electrostatic spraying and sol-gel, and was characterized by SEM, XPS and EDX. Batch experiments were performed to evaluate the adsorption capacity at different conditions: pH, temperature, initial concentration, adsorbent dosage and contact time. The results showed that the adsorption kinetics data correlated well with the pseudo-second-order kinetic model and the adsorption isotherm was well described by the Langmuir isotherm model with the maximum capacity of 16.06 mg·g−1 for CMKGM-La microspheres at pH of 4 and 318.15 K. The adsorption of phosphorus was a spontaneous, entropy-increasing and endothermic process. The possible adsorption mechanism of phosphorus on the CMKGM-La microspheres consisted of the coordination reaction of La (III) with phosphorus and electrostatic attraction between protonated hydroxyl and phosphorus. The presence of co-existing ions (such as NH4+, Cl−, SO42−, SiO32− and CO32−) had no significant effect on phosphorus removal. These results suggested that the adsorbent of CMKGM-La microspheres was a promising adsorbent for the removal of phosphorus from slaughterhouse wastewater.

Preparation of Modified Konjac Glucomannan Nanoparticles and their Application as Vaccine Adjuvants to Promote Ovalbumin-Induced Immune Response in Mice.

Herein, we reported a facile strategy for synthesis of two types of modified konjac glucomannan nanoparticles (NPs). The goal of this project was to explore the potential of the NPs as vaccine adjuvants. Firstly, anionic carboxymethylated konjac glucomannan (CKGM) and cationic quaternized konjac glucomannan (QKGM) were synthesized by chemical modification of konjac glucomannan (KGM). Subsequently, two types of NPs, CKGM/QKGM and sodium tripolyphosphate (TPP)/QKGM, were prepared through polyelectrolyte complex method and ionic cross-linking method, respectively. The thus-synthesized NPs were then loaded with ovalbumin (OVA) to further evaluate the effect of NPs on immune response in mice. The encapsulation efficiency of OVA for CKGM/QKGM/OVA and TPP/QKGM/OVA NPs could be 49.2% and 67.7%, respectively, while the drug loading capacity could reach 10.9% and 60%. The NPs showed irregular spherical shape and exhibited good sustained-release properties. In vitro cytotoxicity assay revealed that both the blank and OVA-loaded NPs were not toxic to cells. The OVA-specific IgG, splenocytes proliferation and cytokine levels indicated that the OVA-induced humoral and cellular immune responses were up-regulated by OVA-loaded NPs. What's more, CKGM/QKGM/OVA NPs elicited both higher IL-2 and IFN-γ production, while TPP/QKGM/OVA NPs elicited both higher IL-4 and IL-10 production. These results suggest that TPP/QKGM and CKGM/QKGM NPs are promising to be used as vaccine adjuvants. The TPP/QKGM/OVA NPs could induce stronger humoral immune response, while CKGM/QKGM/OVA NPs could enhance the cellular immune response more effectively.