Konjac Powder Research Articles

こんにゃく粉を使用した服薬用とろみ水の力学的特性

The mechanical properties of moderately dilute solution of Konjac powder (KP) and its hydrolysates (hKP) were characterized by viscosity and texture profile analysis. hKP was prepared by partial acid hydrolysis of KP in 70% ethanol solution at 130°C. The viscosities of 0.3%～0.5% KP solutions and 0.6%～1.0% hKP solutions were about 50～500 mPa·s and 80～400 mPa·s respectively. The hKP solution moved around the mouth more slowly and allowed better control of swallowing than KP solution. This indicates that hKP may be useful as a thickener to take medicine due to its low adhesiveness.

곤약의 최적 응고 및 항미생물 활성을 위한 조건 확립

This study was conducted to establish optimum conditions for coagulation of konjac jelly as well as antimicrobial activity by concentration of . Hardness, gumminess, and chewiness of konjac jelly increased according to concentration of konjac powder, the key material of konjac jelly. The highest sensory evaluation score was acquired with konjac jelly made with 3% konjac powder. A concentration of 0.4-0.6% as a coagulation agent was optimum for coagulation of konjac jelly. Further, sensory score was highest at a concentration of 0.6%. All populations of bacteria, yeast, and mold in konjac jelly were restrained by in a concentration- dependent manner. Furthermore, all tested microorganisms were strictly restrained at N of .

The Components and Activities of Flax-Degumming Enzymes Produced by <i>Bacillus licheniformis</i> HDYM-03

Bacillus licheniformis HDYM-03 was isolated from flax-retting water. In this research, the production of flax-degumming enzymes by this strain was investigated in four medium, whose sole carbon source was beef extract peptone (BP), pectin (PEC), konjac powder (KGM) and carboxymethylcellulose sodium (CMC), respectively. In PEC medium, the production of pectinase (455.06 U/mL) and polygalacturonase (540.32 U/mL) is higher than that in other medium. In KGM medium, the mannanase reach the highest activity 193.33 U/mL. The production of xylanase and cellulase is extremely lower and could be ignored in all of the four medium. The results show that the production of flax-degumming enzymes by this strain could be significantly induced by flax colloid. B.licheniformis HDYM-03 suggest an applicable potential in flax-retting industry.

Microwave-assisted Acid Hydrolysis of Konjac Products for Determining the Konjac Powder Content

The complete hydrolysis of konjac glucomannan (KGM) with an acid or enzyme generally takes a long time. To accelerate KGM hydrolysis without diminishing the conventional quality, a diluted acid hydrolysis of KGM with sulfuric acid was conducted using a microwave digestion system. The optimum conditions of microwave-assisted acid hydrolysis for KGM were: 10 mL of 0.25 M sulfuric acid, hydrolysis temperature of 135°C (microwave power of 600 W), and total microwave-irradiation time of 45 min. The yields of the component sugars, mannose and glucose, from two konjac powders were similar to those by conventional acid hydrolysis with 1 M sulfuric acid in a boiling water bath for 5 h. Furthermore, a pretest for microwave-assisted acid hydrolysis using mixtures of konjac powder and starch at different ratios proved that their konjac content can be calculated by determining the mannose generated by the new rapid hydrolysis method, if the raw materials are provided.

Gene Cloning and Enzymatic Characterization of an Alkali-Tolerant Endo-1,4-β-mannanase from Rhizomucor miehei

An endo-1,4-β-mannanase gene (RmMan5A) was cloned from the thermophilic fungus Rhizomucor miehei for the first time and expressed in Escherichia coli . The gene had an open reading frame of 1330 bp encoding 378 amino acids and contained four introns. It displayed the highest amino acid sequence identity (42%) with the endo-1,4-β-mannanases from glycoside hydrolase family 5. The purified enzyme was a monomer of 43 kDa. RmMan5A displayed maximum activity at 55 °C and an optimal pH of 7.0. It was thermostable up to 55 °C and alkali-tolerant, displaying excellent stability over a broad pH range of 4.0-10.0, when incubated for 30 min without substrate. The enzyme displayed the highest specificity for locust bean gum (K(m) = 3.78 mg mL⁻¹), followed by guar gum (K(m) = 7.75 mg mL⁻¹) and konjac powder (K(m) = 22.7 mg mL⁻¹). RmMan5A hydrolyzed locust bean gum and konjac powder yielding mannobiose, mannotriose, and a mixture of various mannose-linked oligosaccharides. It was confirmed to be a true endo-acting β-1,4-mannanase, which showed requirement of four mannose residues for hydrolysis, and was also capable of catalyzing transglycosylation reactions. These properties make RmMan5A highly useful in the food/feed, paper and pulp, and detergent industries.

High-level production of a cold-active B-mannanase from Bacillus subtilis Bs5 and its molecular cloning and expression

Mannanases can be useful in the food, feed, pulp and paper industries. In this research a Bacillus subtilis strain (named Bs5) which produced high-level beta-mannanase was isolated. Maximum level of beta-mannanase (1231.41 U/ml) was reached when Bacillus subtilis Bs5 was grown on konjac powder as the carbon source for nine hours at 32 degrees C. The beta-mannanase was a typical cold-active enzyme and its optimal temperature of 35 degrees C was the lowest among those of the known mannanases from bacteria. In addition, the optimal pH was 5.0 and much wide pH range from 3.0-8.0 was also observed in the beta-mannanase. These properties make the beta-mannanase more attractive for biotechnological applications. The DNA sequence coding the beta-mannanase was cloned and the open reading frame consisted of 1089 bp encoding 362 amino acids. A phylogenetic tree of the beta-mannanase based on the similarity of amino acid sequences revealed that the beta-mannanase formed a cluster with the beta-mannanases of Bacillus subtilis, which was separated from the mannanases of fungi and other bacteria. The beta-mannanase gene could be expressed in Escherichia coli and the recombinant beta-mannanase was characterized by Western blot. This study provided a new source of carbohydrate hydrolysis enzyme with novel characteristics from Bacillus subtilis.

High level expression of a novel β-mannanase from Chaetomium sp. exhibiting efficient mannan hydrolysis.

A novel β-mannanase gene (CsMan5A) was cloned from Chaetomium sp. CQ31 and expressed in Pichia pastoris. It had an open reading frame of 1251bp encoding 416 amino acids and contained two introns. The deduced amino acid sequence shared the highest similarity (73%) with the β-mannanase from Emericella nidulans and belongs to glycosyl hydrolase family 5. The recombinant β-mannanase (CsMan5A) was secreted at extremely high levels of 50,030UmL-1 and 6.1mgmL-1 in high cell density fermentor. The purified enzyme was optimally active at pH 5.0 and 65°C and displayed broad pH stability (pH 5.0-11.0) and exhibited specificity towards locust bean gum (Km=3.1mgmL-1), guar gum (Km=9.3mgmL-1) and konjac powder (Km=10.5mgmL-1). It efficiently degraded mannan polysaccharides into mannose and mannooligosacccharides, and also hydrolyzed mannotriose and mannotetraose. These properties make CsMan5A highly useful in food, feed and paper/pulp industries.

A Novel Processing Technique for the Production of Instant Rice Noodle with a Long Shelf-Life

Using additives to prevent retrogradation together with traditional Chinese fermentation technology for rice noodles and the steam sterilizing technique used in the preparation of Japanesewudonoodles, we have developed a novel processing technique which will be discussed in this report. The major changes in rice compositions during fermentation were compared, and the effects of various anti-retrogradation additives on the freshness of instant rice noodle during storage were also measured. The results showed that rice noodles produced by fermentation have a better texture and flavor than those which are not fermented; products which have been wrapped without the addition of any preservatives but which have been steam-sterilized at 90-95 °C for 30-25 min can be stored for 24 months without any deterioration; however, additives such as plant oil, konjac powder and potato starch etc. prevent retrogradation and insure that instant rice noodles remain fresh during storage; β-amylase has been found to be the most effective reagent in this respect.

A Novel Cold-Active and Alkali-Stable β-Glucosidase Gene Isolated from the Marine Bacterium Martelella mediterranea

A β-glucosidase gene designated gluc3m was cloned through construction of a genomic library of Martelella mediterranea 2928. The gluc3m consisted of 2,496bp and encoded a peptide of 832 amino acids that shared the greatest amino acid similarity (59%) with a β-glucosidase of family 3 glycoside hydrolase from Agrobacterium radiobacter K84. The optimum reaction temperature and pH of Gluc3M were 45°C and 8.0, respectively. The K (m) and V (max) for p-nitrophenyl-β-D: -glucopyranoside were 0.18mg/ml and 196.08µmol/min/mg enzyme, respectively. Gluc3M was found to be highly alkali stable, retaining 80% of its maximum enzymatic activity after treatment with pH 11.0 buffers for 24h. Furthermore, the activity of Gluc3M improved remarkably in the presence of univalent metal ions, whereas it was inhibited in the presence of divalent ions. Gluc3M also exhibited significant activities toward various substrates including pNPGlu, pNPGal, salicin, and konjac powder. It is important to note that Gluc3M is a cold-active enzyme that showed over 50% of the maximum enzymatic activity at 4°C. SWISS-MODEL revealed that the amino acids near the conserved domain SDW of Gluc3M contributed to the cold-active ability. Based on these characteristics, Gluc3M has the potential for use in additional studies and for industrial applications.

Interior Structure of Fiber Breads Containing Corn Husk, Wheat Bran, Konjac Powder, and Gobo Residue for Scanning Electron Microscopy

Interior Structure of Fiber Breads Containing Corn Husk, Wheat Bran, Konjac Powder, and Gobo Residue for Scanning Electron Microscopy

Investigation of nanostructure of konjac-based water absorbents with atomic force microscopy

Atomic force microscopy technology is gradually spreading to almost all aspects, including food science and technology, since it was first invented in 1986. In this study, this powerful instrument was applied to image nanostructures of three water absorbents-original konjac powder, konjac powder grafted with acrylic acid using 60Co γ-irradiation and regenerated grafted powder. Water absorption capacities and the rates of the three absorbents were also determined in this work. Original konjac powder could only absorb 60 times (w/w) of water, while 270 times for the grafted absorbent and 360 times for the regenerated absorbent. The initial water absorption rates in both tap and distilled water were high, but the rate decreased steeply as time elapsed. After 20 min, the absorbent was close to saturated status. These physical properties were in accordance with the nanostructures of these three water absorbents.

An alternative carbon source from konjac powder for enhancing production of bacterial cellulose in static cultures by a model strain Acetobacter aceti subsp. xylinus ATCC 23770

A new carbon source for bacterial cellulose production was successfully developed from konjac powder by using dilute acid hydrolysis and was detoxified by different alkaline treatment methods to remove microbial growth inhibitors. The various treatments included the addition of calcium hydroxide or sodium hydroxide to pH 10, and subsequent adjustment of the pH to 5 with acid as well as treatment with activated charcoal or laccase, respectively. The results showed that the detoxification effect using Ca(OH) 2 was much better than that using NaOH. If activated charcoal or laccase was added in the process, the detoxification effects would go further and bacterial cellulose production could be improved more. Based on the same concentration of total sugars, bacterial cellulose production using the hydrolyzates was three times higher than that using glucose, six times higher than that using mannose, and five times higher than that using glucose–mannose mixture as carbon source in static cultures. The addition of extra calcium in glucose media in the form of CaCl 2 at pH 5 did result in an improvement of less than 50% in BC production, which was not comparable to the Ca(OH) 2 treatments at pH 10. The possible mechanisms behind the findings were discussed and potential stimulatory factors for the fermenting bacterium formed during the alkaline processing deserve further attention. The results indicate that konjac powder could serve as a feedstock for bacterial cellulose production and cultivation of Amorphophallus rivieri Durieu would bring more economic benefits to farmers in future.

Optimization of medium composition for the production of alkaline β-mannanase by alkaliphilic Bacillus sp. N16-5 using response surface methodology

In this work, a 2(2) factorial design was employed combining with response surface methodology (RSM) to optimize the medium compositions for the production of alkaline beta-mannanase by alkaliphilic Bacillus sp. N16-5 isolated previously from sediment of Wudunur Soda Lake in Inner Mongolia, China. The central composite design (CCD) used for the analysis of treatment combinations showed that a second-order polynomial regression model was in good agreement with experimental results, with R (2) = 0.9829 (P < 0.05). The maximum activity was obtained at NaCl concentration (84.4 g l(-1)) and sodium glutamate (3.11 g l(-1)) and a high medium pH around 10.0. Under such conditions, the activity of alkaline beta-mannanase achieved 310.1 U/ml in the scale of 5-l fermenter, which was increased nearly twice compared with the original. Through optimization, the substrates shifted from the expensive substrates, such as locust bean gum and peptone, to the inexpensive ones such as konjac powder, soymeal, and sodium glutamate. The experiment results also suggested that the environmental conditions of high salinity and high alkalinity, as well as the inducer substrates, play very important roles in the production of the alkaline beta-mannanase by alkaliphilic Bacillus sp. N16-5.

Characteristics of galactomannanase for degrading konjac gel

Galactomannanase (Glmnase) is an enzyme product derived from Aspergillus niger. The activity of Glmnase degrading (hydrolyzing) the konjac gel were investigated. Significant loss in the enzyme activity was found when the temperature above 60 °C. Similar observations were obtained when the reaction pH above 5. Further increase in the pH value resulted in entirely loss of enzyme activity at the alkaline pH region (pH 8.0 and above). The optimal hydrolyzing temperature and pH were at 60 °C and 5.0, respectively. For the stability test, the purified Glmnase increased its thermostability up to 70 °C at pH 5.0, but it retained only about 60% activity after 60 min incubation at this temperature and its activity became zero after 20 min incubation at 80 °C. The Glmnase was stable at the pH range from 3.0 to 7.0 at room temperature and retained at least 80% activity for 60 min. For the storage temperature test, the lyophilized Glmnase still conserved about 90% activity during 7 days at 30 °C, and was higher than about 80% at 4 °C. The K m and V max, were 0.018 mg/ml konjac powder and 0.20 mg/ml reducing sugar per min, respectively.

High-level production, purification and characterization of a thermostable β-mannanase from the newly isolated Bacillus subtilis WY34

A newly isolated Bacillus subtilis WY34 produced high level of mannanase (1105 U/ml) when grown on konjac powder as the carbon source at 50 °C. The β-mannanase was purified 5.4-fold to homogeneity with a final recovery of 20.3% and a specificity of 8302.4 U/mg protein. The purified mannanase appeared as a single protein band on SDS–PAGE gel with a molecular mass of approx. 39.6 kDa. It was identified as a glycoprotein by periodic acid-Schiff staining with a carbohydrate content of 13.1%. The first 10 N-terminal amino acid sequence (HTVSPVNPNA) of the purified enzyme showed high homology (90% identity) with the N-terminal region of β-mannanase from B. subtilis NM-39. The optimal temperature and pH for mannanase activity was 65 °C and pH 6.0, respectively. The mannanase activity was stable within pH 5.5–10.1. It was stable up to 60 °C at pH 6.0. The mannanase was highly specific towards locust bean gum, but exhibited very low activity towards starch, CMC and birchwood xylan. Apparent K m values of the mannanase for locust bean gum, guar gum and konjac powder were 7.6, 10.5 and 27.4 mg ml −1, respectively. Copra mannan was degraded mainly to mannotetraose, mannobiose and mannotriose when incubated with the mannanase, suggesting that the mannanase is an endomannanase and is suitable for mannooligosaccharide production. These unique properties of the purified β-mannanase from B. subtilis WY34 make this enzyme attractive for biotechnological applications.

A New Immunomodulatory Function of Low-Viscous Konjac Glucomannan with a Small Particle Size: Its Oral Intake Suppresses Spontaneously Occurring Dermatitis in NC/Nga Mice

Background: Konjac glucomannan (GM) is a well-known dietary fiber with various beneficial functions: the higher viscosity displayed the stronger potency. However, the high-viscous GM powders, ordinary konjac powder and highly purified GM were mostly unsuitable for the application to various food industries. Our aims are to develop new physiological functions of low-viscous GM powder, pulverized GM or re-granulated fine GM, using a murine model of atopic dermatitis. Methods: Male 4-week-old NC/Nga mice were fed for 8 weeks on diets containing 5% of two high-viscous and two low-viscous GM powders, respectively. Results: Striking suppression against the aggravation of dermatitis, the increase in scratching behaviors, and the rise in IgE levels was recognized only in mice fed on the pulverized GM diet, but not in mice fed on the other GM diets or a control diet. Eczema prevention in the fine GM-fed mice was accompanied by a significant decrease in their plasma IFN-γ levels, a positive regulatory cytokine for atopic skin inflammation. Conclusion: Only the pulverized GM possessed the ability to suppress the development of dermatitis in NC/Nga mice. This is the new immunomodulatory function of low-viscous GM with a small particle size.

Kinetics of beta-mannanase fermentation by Bacillus licheniformis.

fs, fraction parameter; Kp, constant in Equation (6) (g l(-1)); Ks, Monod constant for bacteria growth (g l(-1)); m, maintenance coefficient (g g(-1) h(-1)); P, beta-mannanase concentration (g 1(-1)); qm, constant in Equation (6) (h(-1)); S, substrate concentration (g l(-1)); S0, initial substrate concentration (g l(-1)); Si, insoluble substrate concentration (g l(-1)); Ss, soluble substrate concentration (g l(-1)); t, fermentation time (h); tL, lag time (h); mu, specific growth rate (h(-1)); mu(max), maximum specific growth rate (h(-1)); X, biomass concentration (g l(-1)); YP/S, beta-mannanase yield on carbon substrate (g g(-1)); YX/S, biomass yield on carbon substrate (g g(-1)).

A kinetic correlation for konjac powder hydrolysis by β-mannanase from Bacillus licheniformis

The kinetics of konjac powder hydrolysis by β-mannanase from Bacillus licheniformis was studied for the production of manno-oligosaccharides, a bifidobacteria factor. It is assumed that, during the whole reaction, the substrate has an average degree of polymerization with which the apparent kinetic constants, K m and k +2, vary and the concentration of substrate remains unchanged. Based on the above assumptions, a set of simple expressions is proposed to correlate the initial concentration of substrate, enzyme concentration, degree of hydrolysis and reaction time. The results predicted are in good agreement with the experimental data.

.BETA.-1,4-Mannanases from marine bacteria, Vibrio spp. MA-129 and MA-138.

Two marine bacteria capable of producing extracellular β-1, 4-mannanases (strain nos. MA-129 and MA-138) were isolated from sea environment. A large amount of β-mannanases were induced with konjac powder from both strains and also with mannose from strain no. MA-138. Both strains showed high enzyme production when incubated with shaking at 25°C for 24h. The culture fluid of strain no. MA-129 was fractionated into one active peak and that of strain no. MA-138 two active peaks by ion-exchange chromatography. Every enzyme fraction had pH optimum of 7.0-7.5 and hydrolyzed β-mannan and glucomannan to form several oligosaccharides. Both strains belonged to genus Vibrio.

Production of \-mannanases by Trichoderma harzianum E58

The extracellular mannanase and endoglucanase activities of Trichoderma harzianum E58 were followed during growth of the fungus on 1% (w/v) mannose, Avicel, locust bean gum, konjac powder or the water-soluble fraction from stream-treated white spruce (SWS). Peak galactomannanase activities of 0.60 IU/ml and 0.66 IU/ml were detected in culture filtrates after 6–8 days growth on locust bean gum and Avicel respectively. When SWS or konjac powder were used as substrates, lower but relatively constant levels of activity were detected between 2 and 11 days of growth. Growth of the fungus on mannan-rich locust bean gum resulted in the highest specific glucomannanase and galactomannanase values. Although growth on 1% mannose failed to induce any mannanase activity, when 0.5% galactomannan was added with mannose, mannanase activity was detected in the culture filtrate. This indicated that mannanase production was not repressed in the presence of mannose. Samples were taken from each culture at the time of maximum galactomannanase activity. A protein profile obtained by isoelectric focusing was followed by a zymogram overlay to detect bands exhibiting galactomannanase, glucomannanase and endoglucanase activities. Several bands showed mannanase and endoglucananase activity. One band at pI 6.55 revealed both gluco- and galactomannanase activity and was free of detectable cellulase activity.