• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.246-250
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• 1995

Konjac(Amorphophallus konjac) glucomannan dispersions were prepared from konjac flour, pretreated konjac flour and purified glucomannan. Konjac glucomannan dispersions showed non-Newtonian fluid behavior without yield stress and higher shear stress at fixed shear rate than the dispersions of gum xanthan, gum carrageenan and sodium alginate. While temperature increased, shear stress at fixed shear rate of konjac glucomannan dispersion steadily decreased. The apparent viscosity of konjac glucomannan dispersion was in its maximum at pH 7, whereas decreased on the outskirts of pH 7. The change in apparent viscosity was not found up to 1% sodium chloride addition in case of konjac glucomannan dispersion. However, the apparent viscosity of konjac glucomannan dispersion decreased up to sugar addition of 10%, afterwards increased.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.799-804
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• 1994

A 0.625% dispersion of the pretreated konjac (Amorphophallus konjac) flour was treated with 3 volumes of ethanol and the precipitate was dried at room temperature to produce purified glucomannan in 67.2% yield. Konjac glucomannan was analyzed for proximate composition and the contents of total dietary fiber and minerals. TLC analysis with a mobile phase of isopropanol : $H_2O$(4 : 1, v/v) revealed the presence of mannose and glucose as component sugars. The molecular mass of konjac glucomannan was in the range between 240 and 370 kDa as determined by HPLC with a Protein Pak 300SW column. Water holding capacity of konjac glucomannan was greater than those of most other gums except guar and xanthan gums. Konjac glucomannan accelerated foam formation of bovine serum albumin. As the concentration of konjac glucomannan increased up to 2%, maximum viscosity increased drastically, whereas the swelling time at maximum viscosity decreased. When swelling temperature increased, maximum viscosity and the swelling time at maximum viscosity decreased simultaneously.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.820-823
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• 2006

Five oligosaccharides were isolated from the hydrolysate of konjac (Amorphophallus konjac) glucomannan by a purified ${\beta}$-mannanase from Trichoderma sp. These oligosaccharides were identified as M-M, G-M, M-G-M, M-G-M-M, and M-G-G-M; where G- and M- represent ${\beta}$-1,4-D-glucopyranosidic and ${\beta}$-1,4-D-mannopyranosidic linkages, respectively. The mode of action of the mannanase on the glucomannan is discussed on the basis of the structure of the above oligosaccharides.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.255-260
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• 1997

Glucomannan was isolated from konjac (Amorphophallus konjac) flour by precipitating in aqueous alcohol solution. Konjac glucomannan films were prepared at various concentrations up to 1.0% (w/v) in aqueous glycerol solutions. Tensile strength (TS), percent elongation (E), water vapor permeability (WVP) as the barrier property and the solubility of the films were varied with glucomannan concentrations, glycerol contents and storage humidities. TS was decreased as the glucomannan concentration in the film and relative humidity for storage increased, and E was vice versa. WVP showed better barrier properties compared with other polysaccharides films. Glycerol contents in the film significantly affccted TS and E, but did not affect WVP. The glucomannan films were completely dissolved in the water by 150 min stirring at room temperature.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.188-194
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• 2013

The effects of white bread supplemented with konjac glucomannan on diet-induced obesity in rats were investigated. Four groups of male Sprague-Dawley rats were examined: a non-obese control group (NC), an obese high fat diet group (HF), an obese high fat diet group given bread supplemented with 10% konjac glucomannan (KGM1) and an obese high fat diet group given bread supplemented with 20% konjac glucomannan (KGM2). The daily weight gain of the KGM1 group increased slightly and decreased in the KGM2 group compared to the HF group. The serum triglycerides, total lipid, total cholesterol, and HDL-cholesterol increased in the HF compared to the NC group, whereas they decreased in KGM1 and KGM2 groups. After having this experimental diet for 6 weeks, the body weight in KGM1 and KGM2 groups decreased compared to the HF group. While the initial R$\ddot{o}$hrer index was 23.13 in the NC group, and 31.50~32.59 in the HF, KGM1, and KGM2 groups, the index after the experimental diets for 6 weeks was 28.39 in the NC group, 36.88 in the HF group, 33.48 in the KGM1 group and 29.64 in the KGM2 group. The level of body fat increased from 1% to 7.14% in the NC group, from 15.60% to 60.05% in the HF group, and from 10.60% to 10.83% in the KMG1 group, but decreased from 10.45% to 8.20% in the KGM2 group. These results demonstrate that white bread with glucomannan is effective in reducing body weight and serum lipids in high fat diet-induced obese rats.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.159-163
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• 2008

Xylogone sphaerospora ${\beta}$-mannanase was purified by Sephadex G-100 column chromatography. The specific activity of the purified enzyme was 8.44 units/ml protein, representing an 56.27-folds purification of the original crude extract. The final preparation thus obtained showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight was determined to be 42kDa. Konjac glucomannan was hydrolyzed by the purified ${\beta}$-mannanase, and then the hydrolysates was separated by activated carbon column chromatography. The main hydrolysates were composed of D.P. (Degree of Polymerization) 3 and 4 glucomannooligosaccharides. For elucidate the structure of D.P 3 and 4 glucomannooligosaccharides, sequential enzymatic action was performed. D.P 3 and 4 were identified as M-G-M and M-M-G-M (G- and M- represent glucosidic and mannosidic link-ages). To investigate the effects of konjac glucomannooligosaccharides on in vitro growth of Bifido-bacterium longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, B. auglutum and B. breve. Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon source such as D.P. 3 and D.P. 4 glucomannooligosaccharides, respectively. B. longum and B. bifidum grew up 3.9-fold and 2.8-fold more effectively by the treatment of D.P. 4 glucomannooligosaccharides, compared to those of standard MRS medium. Especially, D.P. 4 was more effective than D.P. 3 glucomannooligosaccharide on the growth of Bifidobacterium spp.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1186-1191
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• 2004

Bacillus sp. $\beta$-mannanase was purified by DEAE-sephadex ion exchange column chromatography. The partially purified P-mannanase exhibited maximum activity at pH 6.0 and 5$0^{\circ}C$, and was stable at a pH range of 5.5 to 7.0, and at temperature between 30 to 5$0^{\circ}C$. Konjac glucomannan was hydrolyzed by the purified $\beta$-mannanase, and then hydrolysates separated by 1st activated carbon column chromatography and 2nd sephadex G-25 gel filtration. The main hydrolysates were composed of D.P 5 and 7 glucomannooligosaccharides by TLC and FACE method. To investigate the effects of guar gum glucomannooligosaccharides on the in vitro growth of B. longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, and B. breve, Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon SOUTce such as D.P 5, and D.P 7 glucomannooligosaccharides, respectively. B. longum grew up 4.6-fold and 5.3-fold more effectively by the replacement of D.P 5 and 7 glucomannooligosaccharides as the carbon source in a comparasion of standard MRS. Also, B. breve and B. animalis slightly grew up by the treatment of D.P 5 glucomannooligosaccharide.

• The Korean Journal of Rheology
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• v.5 no.2
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• pp.161-169
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• 1993

Glucomannan(G.M.)은 Amorphophallus Konjac C. Koch의 tuber로부터 분리되었고. 이 G.M.은 다시 침전제로 메탄올을 사용하여 4단계로 분별되었다.(F.1, F.2, F.3, F.4,). 각분 별물에 비하여 직선으로부터 벗어남을 보였다. Low shear viscometer로 G.M. 용액의 viscosity를 측정하였고 농도와 zero shear specific viscosity의 logarithm을 도시한 결과 inflection point를 나타내었다. 이것은 G.M. 분자들의 coil overlap의 시작에서 기인한 것이 고 묽은 용액에서 진한 용액으로의 전이행동은 임계농도. C＊=4/[η]에서 일어났고 이때의 zero shear specific viscosity는 10을 나타내었다. 또한 specific viscosity는 묽은 용액에대해 서는 C14로써 변화하였고 진한 요액에서는 C3.0으로변화하였다. G.M.의 고체상태에 대한 유 전성($\varepsilon$＇,$\varepsilon$＂)과 점탄성(C＇,C＂)계수들을 액체질소 온도에서부터 15$0^{\circ}C$ 온도범위에 걸쳐 4단계로 film을 건조시키면서 10Hz에서 측정하였다. G.M. film의 유전성과 점탄성의 허수부 분은 ($\varepsilon$＂, C＂), -10$0^{\circ}C$에서 peak를 나타내었고 이 peak는 hydroxy methyl 기들의 회전 운동에서 생겨난 것이다. 건조시키지 않은 상태의 G.M. film의 유전성과 점탄성의 허수부분 의 값들은 -5$0^{\circ}C$에서 물 분자의 운동에 의하여 생긴 peak를 보였다.

• The Korean Journal of Rheology
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• v.9 no.1
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• pp.27-32
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• 1997

GM 은 Amorphopallus Konjac K. Koch의 tuber의 주성분으로알카리 응고제를 첨가 함에 따라 열적으로 안정한 gel을 형성한다. GM에 침전제로 메탄올을 사용하여 4단계로 분 별하였고 각 분별물(F.1, F.2, F.3, F.4)들은 Mark-Houwink 식을 이용하여 분자량을 산출하 였다. Ubbelohde를 이용한 농도에 따른 환산점도로부터 고유 점성도값을 구한 결과 분자량 이 높은 분별물이 분자량이 낮은 분별물에 비하여 직선으로부터 벗어남을 알수 있었다. 또 한 고유점성도는 분자량이 증가할수록 증가하였고, 분자량 분포 범위가 broad하게 나타났다. GM용액의 frequency와 shear rate에 따른 viscosity를 측정한결과 낮은 frequency에서는 loss modulus(G＂)가 storage modulus(G＂)보다 큰 값을 가졌으나 높은 frequency에서는 G ＇가 G＂보다 크게 나타났다. 이 현상은 분자들의 얽힘에 관한 시간 의존도로써 설명할수 있다. 즉높은 frequency에서는 탄소 사슬간의 얽힘들이 진동기간내에 분자결합이 끊어지기 에 충분한 시간을 갖지 못하여 그 조직이 교차 결합을 한 gel처럼 행동하게 되고 한편 낮은 frequency에서는 탄소사슬들의 얽힘이 풀리고 흐르기에 충분한 시간을 갖게된다. Shear rate에 따른 viscosity값과 frequency에 대한 dynamic viscosity값은 거의 유사한 변화를 나 타내었다.

• Nano
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• v.13 no.10
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• pp.1850113.1-1850113.11
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• 2018

Environmental and energy issues have always been a hot topic of global research. Oil leakage has caused great damage to the environment, affecting a wide area and it is difficult to clean up. In most cases, carbon-based adsorbents are typically utilized to remove oil spills because of their economic benefits and high adsorbent efficiency. At the same time, its excellent material properties can also be used for the preparation of supercapacitors. In this paper, the carbon aerogels were prepared by the one-step method. The prepared materials endowed a 3D network structure with a huge number of micropores and mesoporous, and the material is light-weight, stable, hydrophobic and has affinity for oil (17.02 g/g) to the KGM carbon aerogel. Through the physicchemical characterization, the KGM carbon aerogel shows specific surface area is $689m^2/g$, high water contact angle ($136.64^{\circ}$) and excellent reusability (more than 15 cycle times). In addition, we also discussed the electrochemical properties of the material and obtained the specific electrical capacity of 139 F/g under the condition of 1 A/g.