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Concept: Konjac


To study the preparation and separation of Konjac oligosaccharides, Konjac Glucomannan was degraded by the combination of γ-irradiation and β-mannanase, and then the degradation product was separated by ultrafiltration. To our interest, for most of Konjac oligosaccharides obtained by this method, the molecular mass was lower than 2200Da. In addition, the 1000Da molecular weight cut off membrane could effectively separate the Konjac oligosaccharides. In conclusion, the combination of γ-irradiation and β-mannanase was an efficient method to obtain Konjac oligosaccharides, and the oligosaccharides of molecular mass lower than 1000Da could be effectively separated by ultrafiltration.

Concepts: Molecule, Mass, Atomic mass unit, Molecular mass, Separation, Glucomannan, Konjac, Shirataki noodles


TEMPO-oxidized Konjac glucomannan (OKGM) was developed as new material for preparing vegetarian hard capsules. OKGM of different degrees of oxidation: DO30%, DO50%, and DO80% were prepared to select optimum DO for capsule formation. FT-IR results proved that the primary alcohol groups on KGM were oxidized into carboxyl groups. XRD analysis suggested that TEMPO-oxidation decreased the crystallinity of KGM. DO80% was considered as the optimum candidate for capsule preparation owing to its superior solubility, transparency and reduced viscosity. The hydrophilicity of OKGM films, measured by contact angle measurement, increased with increasing DO. The elongation at break and tensile strength of the OKGM films enhanced with increasing DO. In vitro drug dissolution profile of OKGM capsules showed that the shell rupture time of DO80% capsule is about 5-10min, and 80% of the drugs were released within 30-45min. Thus DO80% OKGM was qualified to be used for gastric soluble hard capsules.

Concepts: Alcohol, Carbon dioxide, Iron, Redox, Solubility, Glucomannan, Konjac, Shirataki noodles


Changes in body composition and blood chemistries between overweight adult subjects receiving a supplement containing either 3 g of konjac glucomannan/300 mg calcium carbonate or a placebo containing only 300 mg of calcium carbonate were compared as the primary objective. A secondary objective was to compare outcome differences between compliant and partially compliant subjects.

Concepts: Protein, Nutrition, Calcium carbonate, Dieting, Calcite, Glucomannan, Konjac, Shirataki noodles


Glucomannan (GM), a soluble fiber derived from the plant Amorphophallus konjac, is marketed as being helpful in reducing body weight. However, the data supporting this claim are scarce. The aim of this review was to systematically evaluate the effects of GM on body weight (BW) and body mass index (BMI) in otherwise healthy obese or overweight children and adults.

Concepts: Nutrition, Obesity, Randomized controlled trial, Mass, Body mass index, Body shape, Body weight, Konjac


A nonwoven fabric of Konjac glucomannan (KGM) for the adsorption of tannin was fabricated by using electrospinning and then followed by deacetylation with alkaline solution. To analyze the adsorption dynamics of tannin, the time course of the adsorption of tannin on the nonwoven KGM fabric was measured by immersing the fabric in tannin solution at different concentrations of tannin and amounts of the fabric. The initial and late stages of the adsorption behavior could be expressed, respectively, by using a diffusion-limited equation and a stoichiometric equation. A discussion on the dependence of the control parameters on the adsorption behavior is presented. The results represent the first step to provide an effective adsorption procedure for tannin in the use of modified KGM fabric.

Concepts: Chemistry, Glucomannan, Konjac, Shirataki noodles


Konjac glucomannan (KGM) is a water-soluble dietary fibre extracted from Amorphophallus konjac K. Koch (Araceae). Konjac fibre has been clinically proven as an effective antioxidant agent in weight control but its traditionally known tumour suppression property remains to be explored.

Concepts: Glucomannan, Konjac, Shirataki noodles, Amorphophallus


In this paper, carboxymethyl konjac glucomannan (CMKGM) was obtained by carboxyl modification of konjac glucomannan. Then CMKGM and chitosan (CS) were crosslinked and freeze-dried to prepare CMKGM/CS composite sponges with different proportions. The structure and micromorphology of CMKGM/CS sponges were investigated by FTIR spectroscopy and SEM. The SEM results showed that the pore structure of the composite sponge gradually increased with the increase of CMKGM content. To assess the applicability of CMKGM/CS composite sponges as wound dressing, the swelling behavior, water vapor transmission rate (WVTR), biocompatibility (cytotoxicity and hemolysis) were analyzed. The results indicated that CMKGM/CS composite sponges possessed high swelling ratio, proper WVTR and good biocompatibility, which might accelerate tissue regeneration. Meanwhile, in vivo experiments demonstrated that CMKGM/CS composite sponges could effectively heal full-layer wound of skin defects of male ICR mice.

Concepts: Water, Cellular differentiation, Polysaccharides, Glucomannan, Konjac, Shirataki noodles


Cationic derivatives of konjac glucomannan (KGM) were homogeneously synthesized by reacting KGM with 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC) in NaOH/urea aqueous solutions. The derivatives were characterized by FT-IR, 1H NMR, elemental analysis, thermogravimetric analysis and zeta potential analysis. The results showed that the degree of substitution (DS) of the CKGM with the value of 0.15-0.46 could be obtained by changing the molar ratio between KGM and CHPTAC. The TG/DTG revealed that the thermal stability of KGM after cationization was lower than that of raw KGM. Among a wide range of pH value, the zeta potential in CKGM solution was shown with positive charges. The flocculation capacity of the CKGM was assessed through Kaolin suspension using the light transmission test. The results exhibited that the CKGM had excellent flocculation performance and could be used as an emerging flocculant agent in the wastewater treatment.

Concepts: Concentration, Chemistry, Colloid, Solutions, Aqueous solution, Suspension, Glucomannan, Konjac


This study was to evaluate the protective effects of a dietary fiber, konjac glucomannan (KGM) from the plant tuber of Amorphohallus konjac on Bifidobacteria against antibiotic damage. KGM (∼8.8×108Da) was partially degraded with high-intensity ultrasound to KGM-US (∼1.8×106Da) and then hydrolyzed with trifluoroacetic acid (TFA) to KGM-AH (1369Da). KGM-US (at 5g/l) showed the most significant protective effect on most bifidobacterial strains against penicillin and streptomycin inhibition, increasing the minimal inhibitory and bactericidal concentration (MIC and MBC) dramatically, and KGM also showed significant effects on enhancing the MBC of enrofloxacin, penicillin, tetracycline and streptomycin. In addition, the adsorbance ability and biofilm formation effects of KGM and degraded KGM products may be partially responsible for the protective effects. The results suggested that natural KGM and ultrasound treated KGM have protective effects for the human gut probiotic bacteria against the damage caused by specific antibiotics.

Concepts: Bacteria, Gut flora, Microbiology, Antibiotic resistance, Antibiotic, Probiotic, Glucomannan, Konjac


Intelligent hydrogels are attractive biomaterials for various applications, however, fabricating a hydrogel with both adequate self-healing ability and mechanical properties remains a challenge. Herein, a series of novel intelligent konjac glucomannan (KGM)/microcrystalline cellulose (MCC) hydrogels were prepared vis the mussel-inspired chemistry. MCC was firstly functionalized by the oxidative polymerization of dopamine, and the intelligent hydrogels were obtained by mixing aqueous solutions of KGM and functionalized MCC (PDMCC). By introducing PDMCC, a more compact interconnected porous structure formed for the resulting hydrogels. The self-healing ability and mechanical properties of intelligent hydrogels were dependence on the PDMCC content. Compared with KGM hydrogels, KGM/PDMCC hydrogels exhibited a more distinct pH sensitivity and a lower initial burst release, which was attributed to the compact structure and strong intermolecular hydrogen bond interaction between PDMCC and KGM. These results suggest that the KGM/PDMCC intelligent hydrogels may be promising carriers for controlled drug delivery.

Concepts: Hydrogen, Concentration, Chemistry, Aqueous solution, Hemicellulose, Glucomannan, Konjac, Shirataki noodles