• Food Science and Preservation
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• v.15 no.4
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• pp.532-541
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• 2008

A central composite design was applied to investigate the effects of the independent variables of NaOH concentration(X1) and extraction time(X2) on dependent variables such as Yield(Y1), Xyl/Ara ratio(Y2), uronic acid(Y3), $\beta$-glucan(Y4) and total sugars(Y5) of hemicelluloses separated from rice bran. The Coefficients of determination(R2) in various models ranged from 0.8626 to 0.9319. Yield increased with increased NaOH concentration and extraction time. The optimum extraction conditions were NaOH concentration at 2.45M and extraction time of 24.2 h. Predicted values at the optimized conditions were acceptable, compared with experimental values. The structural characteristics of an optimum hemicellulose extract were explored. As a result, it showed that the surfaces of hemicellulose had a highly irregular reticulated structure. And also it was both small and large molecular particle in the hemicelluloses. Their average molecular weights were in the ranges $235{\sim}240$ kDa and $8.0{\sim}9.4kDa$, respectively.

• Clean Technology
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• v.25 no.3
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• pp.189-197
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• 2019

In this study an optimization of the preparation conditions of activated carbon with a ternary metal ion material to treat $H_2S$, which is classified as a representative odor substance, was carried out. For a metal ion material for enhancing the adsorption performance of hydrogen sulfide, performance enhancement was confirmed by combining Li and Fe or a ternary combination (K, Li, Fe) based on KI, which is a substance promoting hydrogen sulfide adsorption performance. Also, it was determined by XRD analysis that the reaction of each active substance with $H_2S$ was because of binding. The adsorption performance increased more than 3 times with heat treatment of the adsorbent with nitrogen compared with heat treatment with air. The maximum adsorption constant ($q_m$) value of the optimum adsorbent was 97.07, which is 6 times higher than that of the existing K-based impregnated activated carbon. It was confirmed that the objective adsorption amount ($0.3g\;g^{-1}$) was secured by an equilibrium between the mass transfer rate and adsorption rate. From the results, it was confirmed that the performance improvement was noticeable even when activated carbon with a reagent grade activated carbon particle size was modified. It was confirmed that the adsorption performance exists at high relative humidity levels of 60 and 100%, and the optimized preparation can be applied to a wet process such as a scrubber downstream.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.195-203
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• 2021

Aureobasidium pullulans, a black yeast, produces pullulan, a linear α-glucan composed of maltotriose repeating units linked by α(1→6)-glycosidic linkages. Pullulan can be widely used in food, cosmetic, and biotechnology industries. In this study, we isolated eight strains of A. pullulans from Forsythia koreana, Magnolia kobus DC., Spiraea prunifolia var. simpliciflora, Cornus officinalis, Cerasus, and Hippophae rhamnoides. Among them, A. pullulans MR was selected as the best pullulan producer. The effects of a carbon source, a nitrogen source, and pH on pullulan production were examined. The optimal cultivation conditions for pullulan production by A. pullulans MR were determined by response surface methodology as 15% sucrose, 0.4% soy peptone, and an initial pH of 7 at 26℃. Under these conditions, the predicted pullulan production was 47.6 g/L, which was very close to the experimental data (48.9 g/L).

• Journal of the Korean GEO-environmental Society
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• v.18 no.4
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• pp.23-29
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• 2017

As the Enforcement Ordinance of Environmental Policy Act was revised in 2013, Total Organic Carbon (TOC) was added as an indicative parameter for organic matter in Water and Aquatic Ecosystem Environmental Criteria. Under these imminent circumstances, a regulatory standard is needed to achieve the proposed TOC limitation control water quality from the STP (Sewage Treatment Plant). In this study, a electrolysis utilizing the electrochemical reaction was investigated in lab-scale experiments for the treatment of TOC in sewage effluent. TOC reduction by a electrolysis was investigated response surface methodology using the Box-Begnken methods were applied to the experimental results. A central composite design was used to investigate the effects of the independent variables of electrode space ($x_1$), current density ($x_2$) and electrolyte concentration ($x_3$) on the dependent variables removal efficiency of TOC (y). The optimal conditions for electrolysis were determined: electrode space, current density and electrolyte concentration were 50 mm, $10.3mA/cm^2$ and 0.1M, respectively. Statistical results showed the order of significance of the independent variables to be electrode space > current density > electrolyte concentration.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.640-647
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• 2016

By minimizing fluorescence interference phenomena, aequorin-based luminescence technology can provide a relatively sensitive detection platform with integration of $G{\alpha}16$ protein in order to track internal calcium mobilization by G protein-coupled receptors (GPCR). In this type of cell-based functional assay format, it is essential to optimize the transfection process of a receptor and $G{\alpha}16$ protein. For this study, corticotropin releasing factor receptor subtype 2(CRF2) was set as a model system to generate three stable cells with CRF2 and $G{\alpha}16$ in addition to transiently transfected cells under three different conditions. Agonist (sauvagine) and antagonist (K41498) responses in those cells were analyzed to develop the optimum transfection process. As a result, the effective signal ratio in the dose response experiments of sauvagine and K41498 were at least 10-fold higher (z'=0.77) in CRF2-$G{\alpha}16$ stable cells. For the transient transfection cells, stable expression of $G{\alpha}16$ prior to the CRF2 represented a two-fold higher signal (z'=0.84) than the other cases of transient transfection. In conclusion, for the utilization of transient transfection processes to develop a cell-based GPCR functional assay system, it is suggested to introduce various target receptors after stable expression of $G{\alpha}16$ protein.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.10
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• pp.1307-1313
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• 2011

The mechanical limited slip differential (LSD) in vehicles is being replaced by the electromagnetic LSD because of its fast response and better active control characteristics. The coil housing made of STS 304 is one of the most important parts in the solenoid assembly of the electromagnetic LSD. High geometrical accuracy is a prerequisite for the manufacture of such coil housings, but precision machining is difficult because of the use of STS 304 thin plate and the variance in machining variables. The aim of this study is to optimize the mean and variance of the shape accuracy in the coil housing by finding a robust solution for the machining process conditions. The mean and standard deviation of the jaw contact pressure, cutting speed, and feed rate are considered to be the major parameters for minimizing the geometrical mean and variance. The response surface model based on the second-order Taylor series is combined together to minimize the mean and variance of the shape accuracy of the coil housing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.629-635
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• 2007

Response surface methodology (RSM) was used for the analysis and optimization of the production process of Kochujang added with Maesil extract. The process variables were the amount of Maesil extract ($0{\sim}8%$) and red pepper powder ($6{\sim}10%$). pH and all color characteristics (L*-, a*-, and b*-value) decreased but titratable acidity and water activity increased with the addition of Maesil extract. Amino nitrogen content appeared to decrease with the addition of red pepper powder. The highest sensory flavor score was obtained when 2.20% Maesil extract and 8.62% red pepper powder were blended, the highest sensory taste score with 6.63% Maesil extract and 9.50% red pepper powder, and the highest sensory color score with 7.80% Maesil extract and 8.62% red pepper powder respectively. The point chosen as representative of the optimal area corresponds to $X_1=3.60%,\;X_2=10%\;and\;X_1=4.08%,\;X_2=9.96%$ for physicochemical and sensory quality, respectively.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.86-92
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• 2012

A characteristic study of chlorine dioxide generation by the electrolysis system was performed after chlorite ($ClO_2^-$) is adsorbed from sodium chlorite by a polymer ion exchange resin. A strongly basic anion exchange resin was used and a Ti plate coated with Ru and Ir was used as an electrode. Various parameters such as reaction stirring velocity, reaction temperature, chlorine dioxide product concentration, ion exchange resin content and product maker type for the adsorption quantity in the chlorite adsorption of ion exchange resin were investigated and found the ion exchange resin with the maximum adsorption quantity. A generation trend of chlorine dioxide was observed by the electrolysis system and optimum conditions on the desired value were found using response surface design of DOE (Design of Experiments). The strongly basic anion exchange resin with the maximum adsorption quantity was SAR-20 (TRILITE Gel type II) and the adsorption quantity was around 110 mg/IER (g). Observed generation optimum conditions of chlorine dioxide were constant-current (electrode area base; $A/dm^2$) and flow rate of $N_2$ gas (4.7 L/min) at the desired value of sterilization (900~1000 ppm, 1 h).

• Journal of Life Science
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• v.20 no.11
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• pp.1589-1594
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• 2010

Glutaraldehyde was used to cross-link chitosan beads to immobilize the crude enzyme $\beta$-glucosidase from Exiguobacterium sp. DAU5. The conditions for preparing cross-linking chitosan beads and immobilization such as concentration of glutaradehyde, cross-linking time, immobilization pH and time were optimized. The chitosan beads were cross-linked with 1.5% glutaraldehyde for 1.5 hr. The immobilized $\beta$-glucosidase had an overall yield of 20% and specific activity of 5.22 U/g. The optimized pH and temperature were 9.0 and $55^{\circ}C$, respectively. More than 80% of its activity at pH 7.0-10.0, 80% at $40^{\circ}C$ for 2 hr and 48% at $50^{\circ}C$ for 1 hr, were retained. However, the immobilization product showed higher pH and thermal stabilities than free enzymes. It also showed high hydrolyzing activity on soybean isoflavone glycoside linkage. These results suggest the broad application prospects of immobilization enzymes.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.843-850
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• 2000

We have produced the microcapsule composed of ${\alpha}-tocopherol$ as a core material (Cm) and the gelatinized polysaccharide as a wall material (Wm). Firstly, we have developed a simple, sensitive, and quantitative analysis method of the microencapsulation product using 5% cupric acetate pyridine solution. We could then optimize all the conditions for the microencapsulation process such as the ratio of [Cm] to [Wm], the temperature of dispersion fluid, and the emulsifier concentration using response surface methodology (RSM). As for the microencapsulation of ${\alpha}-tocopherol$, the regression model equation for the yield of microencapsulation (YM, %) to the change of an independent variable could be predicted as follows : YM=99.77-1.76([Cm]:[Wm])-1.72$([Cm]\;:\;[Wm])^2$. From the ridge of maximum response, the optimum conditions for the microencapsulation of ${\alpha}-tocopherol$ were able to be determined as the ratio of [Cm] to [Wm] of 4.6:5.4(w/w), the emulsifier concentration of 0.49%, and dispersion fluid temperature of $25.5^{\circ}C$, respectively. Finally, the microcapsules produced under the optimal conditions were applied for the analysis of storage stability. The optimal conditions for the storage were found to be the values of pH 9.0 and $25{\sim}35^{\circ}C$. And the storage stability of the microcapsules containing ${\alpha}-tocopherol$ were higher than 99% for a week at pH 9.0 and $25^{\circ}C$.