• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.9
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• pp.1314-1320
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• 2011

Vacuum drying was conducted for a steamed pumpkin-sweet potato slab to improve its quality, convenience and preference as snack. Steamed sweet potato was dried from 30 to $60^{\circ}C$ for 12 hr, after which moisture contents, colors, and taste were evaluated. The lowest moisture content was 0.22% upon vacuum drying at $60^{\circ}C$ for 12 hr. Lightness decreased while other color values (a, b and ${\Delta}E$) increased with increasing drying temperature and drying time. Reducing sugar and soluble solid contents ranged from 98.7~268.11 mg/g and $19{\sim}72^{\circ}Brix$, respectively. Sensory score of the sample was the highest when dried at $50^{\circ}C$ for 6 hr. The optimum drying conditions were predicted to be $48.5{\sim}62^{\circ}C$ and 5.1~7.1 hr by response surface methodology.

• Journal of Ginseng Research
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• v.33 no.2
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• pp.143-148
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• 2009

This study was carried out to detennine the optimal submerged culture conditions for the growth increase of ginseng adventitious roots containing germanium by means of a fractional factorial design with four factors and three levels, using the response surface methodology (RSM). The ginseng (Panax ginseng CA. Meyer) adventitious roots were induced by plant growth regulators and cultured in a liquid SH medium. The effects of various $GeO_2$ and phosphoric acid ($H_3P0_4$) concentrations in the medium, $GeO_2$ addition time and the pH of the medium on the fresh weight of the ginseng adventitious roots were investigated. The optimum pH of the medium and the phosphoric acid concentration detennined by the partial differentiation of the model equation were 4.7 and 6.0 roM, respectively. The predicted optimal $GeO_2$ concentration was 10 ppm and the $GeO_2$ addition time did not affect the growth of ginseng adventitious roots. Under these conditions, the growth of the ginseng adventitious root containing germanium was predicted to be 2.47 g.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.37-41
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• 2009

In this study, supercritical carbon dioxide extraction (SFE) was utilized for the extraction of tocotrienol from grape seeds. The optimal conditions for vitamin E and tocotrienol extraction were determined via response surface methodology (RSM). Central composite design was utilized to assess the effects of oven temperature (30-$50^{\circ}C$, X1), operating pressure (17-25 MPa, X2), and extraction time (1-5 hr, X3) of supercritical fluid extraction. Vitamin E and tocotrienol contents were 8.65 mg/100 g and 7.88 mg/100 g at $40^{\circ}C$, 20MPa and 5 hr, respectively. The predicted extraction condition was validated via actual experimentation. The predicted extraction conditions were $40^{\circ}C$, 3.8 hr, and 20.7MPa. The vitamin E and tocotrienol contents under these conditions were 8.20 mg/100 g and 7.42 mg/100 g, respectively. The vitamin E and tocotrienol contents of solvent extraction with hexane were 8.18 mg/100 g and 7.24 mg/100 g, respectively.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.24-37
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• 2008

Yeast with excellent ferment ability was isolated and selected from wild grape to manufacture wild grape wine. Wild grape wine by SMR-3 isolated from wild grape was better than other strains in quality, such as high alcohol content and low acidity, residual sugar, organic acid and fusel oil content. Fermentation condition was optimized to manufacture wild grape wine with response surface methodology using isolated SMR-3 as an alcohol fermentation strain. As a result of culture conditions, 10.61% of alcohol content was expected under the conditions of $21.91^{\circ}C$ fermenting temperature, $21.48^{\circ}brix$ of initial sugar content, and 14.65 day of fermentation time. Residual sugar content showed the lowest value at $24.48^{\circ}C$ fermentation temperature, $12.78^{\circ}brix$ of initial sugar content, and 9.02 day fermentation time. The highest level of sensory evaluation was found at $20.23^{\circ}C$ fermentation temperature, $25.30^{\circ}brix$ of initial sugar content, and 5.94 day fermentation time. Ethyl alcohol was the main alcohol component in wild grape wine and fusel oil in wild grape wine was hardly detected; thus, the quality of wild grape wine was considered excellent. The optimal fermentation conditions of wild grape wine was superimposed by deriving a regression equation for alcohol content, fusel oil, ethyl alcohol content, and overall palatability for each variable of wild grape wine. Hence, the optimal fermentation conditions are estimated to be: fermentation temperature $24{\sim}28^{\circ}C$, initial sugar content $20{\sim}24^{\circ}brix$, and fermenting time $12{\sim}14$ days.

• Journal of Aerospace System Engineering
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• v.13 no.3
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• pp.78-86
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• 2019

This paper describes the stiffness optimization of the torsion spring hinge of the large SAR antenna considering the deployment performance. A large SAR antenna is folded in a launch environment and then unfolded when performing a mission in orbit. Under these conditions, it is very important to find the proper stiffness of the torsion spring hinge so that the antenna panels can be deployed with minimal impact in a given time. If the torsion spring stiffness is high, a large impact load at the time of full deployment damages the structure. If it is weak, it cannot guarantee full deployment due to the deployment resistance. A multi-body dynamics analysis model was developed to solve this problem using RecurDyn and the development performance were predicted in terms of: development time, latching force, and torque margin through deployment analysis. In order to find the optimum torsion spring stiffness, the deployment performance was approximated by the response surface method (RSM) and the optimal design was performed to derive the appropriate stiffness value of the rotating springs.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.4
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• pp.415-424
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• 2020

In the present study, we have refined gomisin N, which represents activity in the proliferation of dermal papilla cells (HFDPCs) from the fruit of Schisandra chinensis (S. chinensis), and have identified optimal extraction conditions for obtaining extracts with high content of gomisin N. The activity of the extracts and fractions was evaluated, and the results indicated approximately 29% proliferation activity in the group treated with 1 ㎍/mL of n-hexane fraction. Column chromatography was used to assess the active ingredient in the n-hexane fraction, and two compounds, namely gomisin N(1) and schisandrin(2), were isolated and identified. When the HFDPCs proliferation activity was tested for the isolated compounds, gomisin N exhibited ≥ 20% proliferation activity. Thus, via response surface methodology (RSM), the optimum extraction conditions to obtain the maximum level of gomisin N from the fruit of S. chinensis were determined, where ethanol proportion, extraction time, and extraction temperature were used as the independent variables. The results revealed coefficient of determination ≥ 0.95 and p-value ≤ 0.05, which confirmed the fit of the model. The optimum extraction conditions to achieve the maximum content of gomisin N were as follows: ethanol proportion 83.8%, extraction temperature 80 ℃, and extraction time 8.7 h. The content of gomisin N using these conditions was predicted as 378,300 ppm, and a mean value close to the predicted value (376,884 ppm) was obtained while validating the aforementioned conditions.

• Design & Manufacturing
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• v.17 no.1
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• pp.20-26
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• 2023

Lab-on-a-disc is a circular disc shape of cartridge that can be used for blood-based liquid biopsy to diagnose an early stage of cancer. Currently, liquid biopsies are regarded as a time-consuming process, and require sophisticated skills to precisely separate cell-free DNA (cfDNA) and circulating tumor cells (CTCs) floating in the bloodstream for accurate diagnosis. However, by applying the lab-on-a-disc to liquid biopsy, the entire process can be operated automatically. To do so, the lab-on-a-disc should be designed to prevent blood leakage during the centrifugation, transport, and dilution of blood inside the lab-on-a-disc in the process of liquid biopsy. In this study, the main components of lab-on-a-disc for liquid biopsy are fabricated by injection molding for mass production, and ultrasonic welding is employed to ensure the bonding strength between the components. To guarantee accurate ultrasonic welding, the flatness of the components is optimized numerically by using the response surface methodology with four main injection molding processing parameters, including the mold & resin temperatures, the injection speed, and the packing pressure. The 27 times finite element analyses using Moldflow® reveal that the injection time and the packing pressure are the critical factors affecting the flatness of the components with an optimal set of values for all four processing parameters. To further improve the flatness of the lab-on-a-disc components for stable mass production, a quarter-disc shape of lab-on-a-disc with a radius of 75 mm is used instead of a full circular shape of the disc, and this significantly decreases the standard deviation of flatness to 30% due to the reduced overall length of the injection molded components by one-half. Moreover, it is also beneficial to use a quarter disc shape to manage the deviation of flatness under 3 sigma limits.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1189-1196
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• 1998

Extraction conditions were optimized using response surface methodology for preparing high-quality ethanol extracts from cultivated Chrysanthemum petals. A fractional factorial design was applied to investigate effects of solvent ratio to sample $(X_1)$, ethanol concentration $(X_2)$ and extraction time $(X_3)$ at $60^{\circ}C$ on dependent variables of the extract properties, such as yellow color $(Y_1)$, carotenoids $(Y_2)$, soluble solids $(Y_3)$, phenolic compounds $(Y_4)$, electron donating ability $(Y_5)$, sensory color $(Y_6)$ and sensory aroma $(Y_7)$. Second-order models were employed to generate 3-dimensional response surfaces for dependent variables and their coefficients of determination $(R^2)$ were ranged from 0.8063 to 0.9963. Optimum extraction conditions for each variable were 115 mL/g, 97%, 18 hr in yellow color, 145 mL/g, 50%, 12 hr in carotenoids, 147 mL/g, 48%, 17 hr in soluble solids, 116 mL/g, 68%, 17 hr in phenolic compounds, 110 mL/g, 98%, 14 hr in electron donating ability, 101 mL/g, 48%, 54 hr in organoleptic color and 109 mL/g, 54%, 4 hr in organoleptic aroma, respectively. The range of optimum conditions at 16hr extraction for maximized characteristics of ethanol extracts was $103{\sim}122\;mL/g$ and $64{\sim}78%$. Predicted values at the optimum condition agreed with experimental values.

• Korean Journal of Food Science and Technology
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• v.28 no.3
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• pp.411-416
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• 1996

Supercritical fluid extraction of ${\beta}$-carotene from carrot was optimized to maximize ${\beta}$-carotene (Y) extraction yield. A central composite design involving extraction pressure ($X_1$ 200-,100 bar), temperature ($X_2,\;35-51^{\circ}C$) and time ($X_1$$ 60-200min) was used. Three independent factors ($X_1,\;X_2,\;X_3$) were chosen to determine their effects on the various responses and the function was expressed in terms of a quadratic polynomial equation,$Y={\beta}_0+{\beta}_1X_1+{\beta}_2X_2+{\beta}_3X_3+{\beta}_11X_12+{\beta}_22X_3^2+{\beta}_-12X_1X_2+{\beta}_12X_1X_2+{\beta}_13X_1X_3+{\beta}_23X_2X_3,$ which measures the linear, quadratic and interaction effects. Extraction yields of ${\beta}$-carotene were affected by pressure, time and temperature in the decreasing order, and linear effect of tenter point (${\beta}_11$) and pressure (${\beta}_1$) were significant at a level of 0.001(${\alpha}$). Based on the analysis of variance, the model fitted for ${\beta}_11$-carotene (Y) was significant at 5% confidence level and the coefficient of determination was 0.938. According to the response surface of ${\beta}$-carotene by cannoical analysis, the stationary point for quantitatively dependent variable (Y) was found to be the maximum point for extraction yield. Response area for ${\beta}$-carotene (Y) in terms of interesting region was estimated over $10,611{\mu}g$ Per 100 g raw carrot under extraction.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.3
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• pp.231-245
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• 2023

In the cosmetics industry, it is important to develop new materials for functional cosmetics such as whitening, wrinkles, anti-oxidation, and anti-aging, as well as technology to increase absorption when applied to the skin. Therefore, in this study, we tried to optimize the nanoemulsion formulation by utilizing response surface methodology (RSM), an experimental design method. A nanoemulsion was prepared by a high-pressure emulsification method using Glabridin as an active ingredient, and finally, the optimized skin absorption rate of the nanoemulsion was evaluated. Nanoemulsions were prepared by varying the surfactant content, cholesterol content, oil content, polyol content, high-pressure homogenization pressure, and cycling number of high-pressure homogenization as RSM factors. Among them, surfactant content, oil content, high-pressure homogenization pressure, and cycling number of high-pressure homogenization, which are factors that have the greatest influence on particle size, were used as independent variables, and particle size and skin absorption rate of nanoemulsion were used as response variables. A total of 29 experiments were conducted at random, including 5 repetitions of the center point, and the particle size and skin absorption of the prepared nanoemulsion were measured. Based on the results, the formulation with the minimum particle size and maximum skin absorption was optimized, and the surfactant content of 5.0 wt%, oil content of 2.0 wt%, high-pressure homogenization pressure of 1,000 bar, and the cycling number of high-pressure homogenization of 4 pass were derived as the optimal conditions. As the physical properties of the nanoemulsion prepared under optimal conditions, the particle size was 111.6 ± 0.2 nm, the PDI was 0.247 ± 0.014, and the zeta potential was -56.7 ± 1.2 mV. The skin absorption rate of the nanoemulsion was compared with emulsion as a control. As a result of the nanoemulsion and general emulsion skin absorption test, the cumulative absorption of the nanoemulsion was 79.53 ± 0.23%, and the cumulative absorption of the emulsion as a control was 66.54 ± 1.45% after 24 h, which was 13% higher than the emulsion.