• Journal of the Korean Society of Food Culture
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• v.29 no.5
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• pp.415-420
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• 2014

This study was conducted to establish optimum conditions for coagulation of konjac jelly as well as antimicrobial activity by concentration of $Ca(OH)_2$. 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 $Ca(OH)_2$ concentration of 0.4-0.6% as a coagulation agent was optimum for coagulation of konjac jelly. Further, sensory score was highest at a $Ca(OH)_2$ concentration of 0.6%. All populations of bacteria, yeast, and mold in konjac jelly were restrained by $Ca(OH)_2$ in a concentration- dependent manner. Furthermore, all tested microorganisms were strictly restrained at $1.0{\times}10^{-2}$ N of $Ca(OH)_2$.

• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.11
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• pp.1763-1775
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• 2019

Objective: The influence of konjac gel level on fermentation process and product qualities were assessed to evaluate the feasibility of using it as fat analog in Northeastern Thai fermented sausage (Sai Krok E-san). Methods: Five treatments of fermented sausages were formulated by replacing pork backfat with 0%, 7.5%, 22.5%, and 30% konjac gel. The changes in lactic acid bacteria (LAB) and important physicochemical properties of samples were assessed during 3 days of fermentation. After the end of fermentation at day 3, water activity ($a_w$), instrumental texture, color, microbial counts, and sensory evaluation were compared. The best product formulation using konjac for replacing pork back fat were selected and used to compare proximate composition and energy value with control sample (30% pork backfat). Results: An increase in konjac gel resulted in higher values of LAB, total acidity, and proteolysis index with lower pH and lipid oxidation during 3 days of product fermentation (p<0.05). It was noted that larger weight loss and product shrinkage during fermentation was observed with higher levels of konjac gel (p<0.05). The resulting sausage at day 3 with 15% to 30% konjac gel exhibited higher hardness, cohesiveness, gumminess, springiness, and chewiness than control (p<0.05). The external color of samples with 22.5% to 30% konjac gel were redder than others (p<0.05). Mold, Salmonella spp., Staphylococcus aureus, and Escherichia coli in all finished products were lower than detectable levels. Product with 15% konjac gel had the highest scores of sourness linking and overall acceptability (p<0.05). Conclusion: The product with 15% of konjac gel was the optimum formulation for replacing pork backfat. It had higher sensorial scores of sourness and overall acceptability than control with less negative impact on external appearance (product shrinkage) and weight loss. Moreover, it provided 46% fat reduction and 32% energy reduction than control.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8
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• pp.1195-1204
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• 2019

Objective: The purpose of this study was to investigate whether addition of konjac gel with three different vegetable powders can increase quality of low-fat frankfurter-type sausage. Methods: Low-fat frankfurter-type sausages were manufactured with formulations containing konjac gel and three vegetable powders (aloe vera, cactus pear, or wheat sprout) as pork fat replacers. The formulations of frankfurters were as follows: NF (normal-fat; 20% pork fat), LF (low-fat; 10% pork fat), KG (low-fat; 10% pork fat+10% konjac gel), and konjac gel with three vegetable powders (KV), such as KV-AV (10% pork fat+10% konjac gel with aloe vera), KV-CP (10% pork fat+10% konjac gel with cactus pear), and KV-WS (10% pork fat+10% konjac gel with wheat sprout). Proximate analysis, pH value, color evaluation, cooking loss, water-holding capacity, emulsion stability, apparent viscosity, texture profile analysis, and sensory evaluation were determined. Results: The konjac gel containing groups showed lower fat content (p<0.05) and higher moisture content than NF group (p<0.05). The pH value of frankfurters was decreased in three KV groups (p<0.05). The three KV groups had increased dark color (p<0.05) compared with KG, and KV-CP had the highest redness (p<0.05). The water-holding capacity and emulsion stability were higher in the three KV groups than KG and LF (p<0.05). Cooking loss was generally decreased in the three KV groups, compared with KG (p<0.05). The apparent viscosity of KV groups was similar with NF group and overall texture properties were improved in KV-CP. In the sensory evaluation, the highest overall acceptability was found in KV-CP groups (p<0.05). Conclusion: The four fat replacers improved physicochemical properties of low-fat frankfurters. Particularly, konjac gel with cactus pear powder seems more acceptable as a pork fat replacer.

• 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.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.1008-1014
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• 2016

This study was conducted with the purpose of investigating the rheological characteristics of noodle flour dough supplementary konjac powder comprising 0%, 0.5%, 1.0%, 1.5% or 2.0% of the total mixture. In farinograph analysis, water absorption increased with the increased content of konjac powder. Both the arrival times and the development times of the dough with added konjac powder were longer than original wheat flour dough. Dough stability was found to be increased as compared to the control, but decreased as konjac powder content was increased. As konjac powder content increased, the resistance of the dough as shown by farinograph data was highest in the original wheat flour dough as 130 BU. Starting temperature, maximum viscosity temperature and maximum viscosity were decreased as shown in amylograph analysis. In extensograph analysis, the dough's extensibility and resistance to extension of the dough decreased as the amount of konjac powder was increased. The ratio of resistance to extensibility (R/E) decreased with the an increase in the amount of konjac powder included in the dough. The dough's tensile strength after cooking was increased in proportion to the additional amount of konjac powder used.

• 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.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.5
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• pp.613-619
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• 2013

Konjac gel is known as a low calorie food, because the main component is water. Mugwort has been used for food and medicine for a long time due to itsfunctional property, which contains a lot of vitamins and minerals. Therefore, konjac noodle-added mugwort was prepared. The konjac gel was made by from a centrifuge after adding water, alkali and mugwort power in konjac flour. The centrifuge was used to remove air in the gel. After centrifuging by heating the gel in boiling water for one hour, konjac noodle was made by pressing using a flat heating press. The results are as follows. In the drying process of mugwort freeze drying after blanching in 1% $NaHCO_3$ solution is better than other drying methods. The physical properties (hardness, elasticity, cohesiveness, gumminess) of konjac gel were measured with a Rheometer. The optimum processing conditions were decided by these measured values. The optimum condition of making konjac gel is 9% concentration of konjac flour, a ph of 12.0, $Na_3PO_4$ coagulant and 1.5% concentration of mugwort power in konjac flour.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.282-289
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• 2017

This study was conducted to investigate the noodle-making characteristics of a noodle dough with konjac powder added. The water-binding capacity was significantly increased by increasing amounts of the konjac powder. When the weight and volume of the noodles were measured after cooking, there was no difference between the control and konjac powder groups. Turbidity was significantly reduced in a concentration-dependent manner. Chromaticity, in the case of raw noodle lightness (L), decreased significantly, while redness (a) and yellowness (b) significantly increased. Cooked noodles also showed the same pattern of results, however, as a whole, the results were lower when compared to wet noodles. The texture characteristics of hardness and chewiness significantly increased by increasing concentrations of the konjac powder. Cohesiveness was determined to not be significantly different by observing the surface of the noodle with a scanning electron microscope. In a sensory evaluation of the cooked noodle, no significant differences in gloss, taste, hardness, springiness or overall acceptability were observed between the control and konjac powder groups. This study indicates the that addition of 1.5% konjac powder to noodle dough may improve the functionality and preference of noodles.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.250-253
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• 2004

본 연구는 Soy Protein Isolate, Egg Albumin 및 Konjac의 보습제(humectants)를 첨가하여 제조한 육포의 이화학적, 미생물학적 및 관능적 특성 등을 조사하기 위하여 실시되었다. 보습제를 첨가한 처리구들은 대조구보다 높은 수분함량 및 제품수율을 나타내었으며, 낮은 puncture force를 나타내어 우수한 조직감을 보였다. 모든 처리구가 저장기간이 경과함에 따라 지질산패도 및 총균수가 증가하였으나 konjac을 첨가한 처리구에서 대조구에 비해 다소 낮은 TBA가를 나타냈었다. 또한 Soy protein isolate와 konjac을 첨가한 처리구가 다른 처리구에 비해 낮은 총균수를 나타내었다. 따라서 보습제 종류별 육포의 품질에 미치는 영향이 다소 차이는 있었지만, 저장성면에서 육포 제조시 보습제로서 konjac 첨가가 보다 유효한 것으로 판단된다.