• Korean Journal of Food Science and Technology
• /
• v.27 no.2
• /
• pp.246-250
• /
• 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
• /
• v.26 no.6
• /
• pp.799-804
• /
• 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
• /
• v.15 no.5
• /
• pp.820-823
• /
• 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.

• Journal of the East Asian Society of Dietary Life
• /
• v.15 no.1
• /
• pp.40-48
• /
• 2005

This study was carried out to investigate the effect of body weight reduction of patty containing glucomannan in high fat diet-induced obese rats. Male Spraque-Dawley rats were randomly assigned to control and high fat diets groups for 4 weeks. After 4 weeks, the control and high fat diet groups were rearranged into 5 groups by different levels of patty containing glucomannan (60%). After 5 weeks, serum and whole blood levels were analyzed. Obesity index was significantly lower in the group fed patty containing glucomannan than that of high fat diet groups. The status of white blood cells in hematological examination was significantly higher in rats fed high fat diet and not significantly different from those fed patty. Serum albumin levels were not significantly different, while serum glucose levels were significantly different among groups. Serum Triglyceride and total cholesterol levels were the highest in rats fed high fat diets, while the lowest in rats fed patty containing glucomannan.

• Journal of Food Hygiene and Safety
• /
• v.6 no.2
• /
• pp.73-78
• /
• 1991

As reported previously, it was found that glucomannan, contains a potent cholesterol-lowering material. This study was designed to characterize this material further. Both the water sluble and the alcohol soluble extracts of glucomannan were prepared, and each of these extracts were capable of reducing serum and liver cholestrol levels of rats: This finding indicates that a potent cholesterol-lowering material contained in glucomannan is an organic compound with hydrophilic groups.

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

• Korean Journal of Food Science and Technology
• /
• v.39 no.1
• /
• pp.55-60
• /
• 2007

This study used glucomannan as a fat substitute to produce low-fat patties with chicken meat, of which consumer consumption is increasing. In the case of a cooked meat patty, the crude fat content of the group treated with glucomannan was higher than that of a control when cooked. The cooking loss and reduction rate in the diameter of the control patties were higher than those of the group treated with glucomannan. Cohesiveness and chewiness of the group treated with glucomannan were higher than those of the control. As a result of sensory evaluation, there were no significant differences in the tenderness, color, odor and overall taste among the patties, but the juiciness of the group treated with glucomannan was lower than that of the control. There were no big differences in the pH of the patties during the frozen storage period. The volatile basic nitrogen (VBN) content of all of the types of patties gradually increased up to 7.97-8.56 mg% at the fourth week of storage, but these VBN values are hygienically safe. From these results, there was no large quality difference between a low-fat chicken patty to which glucomannan was added and a control. Therefore, it was confirmed that a good quality low-fat chicken patty can be made by controlling the fat and glucomannan content.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.9
• /
• pp.1324-1332
• /
• 2016

The effects of different hydrocolloids, including hydroxypropyl methylcellulose (HPMC), xanthan gum (XG), guar gum (GG), and glucomannan (GM), on bread quality characteristics were investigated. The composite flour used for bread production consisted of 80% bread flour and 20% rice flour with 1% different hydrocolloids based on baker's%. Loaf volume, specific loaf volume, baking and cooling loss rate, moisture content, crumb texture and color, and sensory evaluation were determined. Breads containing HPMC and GM showed the highest loaf volumes, but the difference was not significant. Bread containing GM showed the lowest baking and cooling loss rate (7.03 and 7.78%, respectively), and the highest moisture content. Breads containing HPMC and GM showed increased springiness and decreased hardness based on texture profile analysis. Cohesiveness, chewiness, and gumminess of breads containing GM and HPMC showed their lowest values, whereas breads containing XG revealed their highest values. Bread with HPMC showed lightest coloured crumbs. In the sensory evaluation, bread containing GM and HPMC presented their highest scores, whereas bread containing XG showed the lowest scores. Overall, HPMC and GM significantly and positively affected quality characteristics of bread.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.3
• /
• pp.469-473
• /
• 2003

This study was conducted to determine the effect of a mixture of two water-soluble dietary fibers, psyllium husk and glucomannan, on serum lipids, fecal fat excretion and body fat. Twenty one female Sprague-Dawley rats were randomly assigned into three groups (control, pair-fed control and test group) and fed a high saturated fat (20% lard) diet (control diet) or a test diet (psyllium husk and glucomannan added to the control diet at the level of 0.9% and 0.68%, respectively) for 8 weeks. Pair-fed control rats were allowed to eat the amount of diet consumed by test group the preceding day. The body weight gain and food efficiency ratio of test group were significantly lower compared with these of control group. The mean values of body weight gain and food efficiency ratio were lower in test group than in pair-fed control group, but the difference was not significant. There were no differences in food intake. The dry weight and water content of feces and fecal fat excretion were markedly greater in test group than in control groups. Serum total cholesterol and triacylglycerol levels were significantly lower in test group than in two control groups.1'he rats of two control groups had higher body fat contents than that of test group. These results indicate that the combination of the two water-soluble dietary fibers, psyllium husk and glucomannan, can be used as a potent lipid-lowering agent in individuals consuming high saturated fat diet.

• Asian-Australasian Journal of Animal Sciences
• /
• v.15 no.7
• /
• pp.1051-1056
• /
• 2002

In vitro binding efficacy of esterified glucomannan (E-GM) (0.1%) on aflatoxin B1 (AF) (300 ppb), ochratoxin A (OA) (2 ppm) and T-2 toxin (T-2) (3 ppm), when present alone or in combination, was evaluated in toxin-contaminated feed at pH 4.5 and 6.5. Esterified glucomannan showed significantly (p<0.01) higher binding with AF (81.6%), whereas those recorded with T-2 (27.8%) and OA (25.6%) were moderate. Binding of each toxin decreased as the number of toxins in feed increased. pH of medium showed no effect on mycotoxin binding ability of E-GM. A $2{\times}2{\times}2{\times}2$ factorial experiment of 5 week duration was conducted to study the effects of two dietary levels each of AF (0 and 300 ppb), OA (0 and 2 ppm), T-2 (0 and 3 ppm ) and E-GM (0 and 0.1%) on the immune competence of a total of 960 day-old commercial broilers. Reductions in size of thymus (by AF and T-2) and bursa (by AF) and antibody titers against Newcastle disease and Infectious Bursal disease (by all the toxins) were noted. Additive and antagonistic interactions were seen among the toxins on certain parameters. Esterified glucomannan significantly (p<0.01) improved antibody titers and weights of bursa ofFabricius and thymus indicating its counteracting efficacy against immunosuppression in mycotoxicosis of multiple origin.