• KSBB Journal
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• v.10 no.2
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• pp.159-165
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• 1995

Methyl fructoside was continuously produced in suspended bed enzyme reactor using alginate-enclosed microspheres biocatalyst which was developed for enzymatic synthesis of methyl fructoside. And the continuous operating conditions were optimized with reactor simulation in order to demonstrate a feasibility of commercialization of the continuous enzymatic production process development. The yield and productivity of methyl fructoside were as high as 47.1%o and $2g/\ell$-hr, respectively. The optimum operating conditions were pH 4.8, 30%(v/v) of methanol content and $2U/m\ell$ of enzyme activity when the initial concentration of sucrose is $0.291mo1/\ell$ at the reaction temperature of $25^{\circ}C$.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.10
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• pp.60-67
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• 2019

Recently, lightweight materials such as Ti alloys have been used increasingly in the aerospace and high-tech industries for weight loss and fuel efficiency. Because of built-up edges and workpiece deflection due to low stiffness, the Ti alloys have poor machinability. In our study, systematic experiments were conducted to investigate the milling characteristics of the Ti alloy (Ti-6A1-4V) with endmills. The independent variables in the experiment were spindle speed, feed per tooth, and axial depth. Cutting force, acceleration RMS, and surface roughness were measured. Using the response surface method, the optimal cutting conditions were analyzed to improve machining quality and productivity.

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.194-199
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• 2008

In this study, the effective method to esterify the free fatty acids in jatropha oil was examined. Compared to other plant oils, the acid value of jatropha oil was remarkably high, 11.5 mgKOH/g. So direct transesterification by a base catalyst was not suitable for the oil. After the free fatty acids were esterified with methanol, jatropha oil was transesterified. The activities of four solid acid catalysts were tested and Amberlyst-15 showed the best activity for the esterification. After constructing the experiment matrix based on RSM and analyzing the statistical data, the optimal esterification conditions were determined to be 6.79% of methanol and 17.14% of Amberlyst-15. After the pretreatment, jatropha biodiesel was produced by the transesterification using KOH in a pressurized batch reactor. Jatropha biodiesel produced could meet the major specifications of Korean biodiesel standards; 97.35% of FAME, 8.17 h of oxidation stability, 0.125% of total glycerol and $0^{\circ}C$ of CFPP.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.173-178
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• 2009

Epidemiological studies showed that high trans-fat consumption is closely associated with getting the risks of cardiovascular disease. The objective of this study was to produce trans-free fat through lipase-catalyzed interesterification, as a substitute for the cream margarine commonly used in industry. Optimum conditions for interesterification in a packed bed enzyme bioreactor (PBEB) were determined using response surface methodology (RSM) based on central composite design. Three kinds of reaction variables were chosen, such as substrate flow rate (0.4-1.2 mL/min), reaction temperature (60-70$^{\circ}C$), and ratio of fully hydrogenated canola oil (FHCO, 35-45%) to evaluate their effects on the degree of interesterification. Optimum conditions from the standpoint of solid fat content (SFC) were found to be as follows: 0.4 mL/min flow rate, 64.7$^{\circ}C$ reaction temperate, and 42.8% (w/w) ratio of FHCO, respectively. The half-life of immobilized lipase in PBEB with two stages at 60$^{\circ}C$ ($1^{st}$ stage) and 55$^{\circ}C$ ($2^{nd}$ stage) was about more than 30 days as estimated by extrapolating the incubation time course of tristearoyl glycerol (TS) conversion, whereas the half-life of the enzyme in PBEB with single stage at 65$^{\circ}C$ was only about 15 days. Finally, the results from SFC analysis suggest that trans-free fat produced in this study seems to be a suitable substitute for the cream margarine commonly used in industry.

• Analytical Science and Technology
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• v.18 no.5
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• pp.396-402
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• 2005

We try to look for optimum conditions of pre-reductants like L-Cysteine, KI and $FeSO_4$ when analyzing inorganic arsenic by using hydride generation-atomic absorption spectrometry, and run a comparative study of effect in the analysis of them. Also, we separated and analyzed only inorganic arsenic by using $H_2SO_4$-trap to eliminate organic arsenic which are MMA(monomethylarsonate) and DMA(dimethylarsinate). Under the conditions of mixture acid of 1.8 M HCl and 0.08 M $HNO_3$, arsenic standard solution of 20 ppb have more higher absorbance than without adding acid. In case of L-Cysteine, As(V) completely reduces into As(III) when 0.5 g of L-Cysteine is reacted more than 30 mins. in weak acid condition of approximately 0.07 M $HNO_3$ or HCl. In the event of KI, As(V) completely reduces into As(III) when 3 g of KI is reacted more than 1hour in acid condition of 0.8 M $HNO_3$. On the occasion of $FeSO_4$, the inside of tube is blocked by precipitation by mixture reaction of $NaBH_4$ and $Fe^{2+}$, therefore, comparing to other pre-reductants, reproducibility of efficiency of reducing As(V) to As(III) is low. To evaluate the accuracy of the analytical results, we use NIST SRM 1643C Trace Elements in Water ($82.1{\pm}1.2ng/mL$). The results are satisfactory.

• Food Science and Preservation
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• v.13 no.4
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• pp.506-512
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• 2006

Gastrodia elata Blume (GEB) is a traditional herbal plant that has been used in Asian countries for centuries as an anticonvulsant analgesic, and a sedative for treating general paralysis, epilepsy, vertigo, and tetanus. This study was designed to optimize conditions for ethanol extracts or GEB by analyzing and monitoring the extraction characteristics with response surface methodology. The extract was used for analysis of the effective components of GEB. The estimated optimal conditions were 63.62% in ethanol of 5.06 mL/g in solvent per sample, and 6.25 hr in extract time. The optimal extraction conditions for $ \gamma-aminobutyric$ acid, were 45.52%, 5.67 mL/g, and 6.04 hr, while those for $\rho-hydroxybenzyl$ alcohol were 62.73%, 5.02 mL/g, and 5.95 hr. Regression equation was generated for each variables and then superimposed them, such as soluble solid, $ \gamma-aminobutyric$ acid and $\rho-hydroxybenzyl$ alcohol content thereby resulting in superimposed values of extinction conditions like $45\sim65%,\;5\sim7mL/g$ and $5\sim7$ hr, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.741-748
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• 2014

This study was conducted to monitor the quality characteristics of Artemisis capillaris ethanolic extract by response surface methodology. The independent variables were extraction temperature ($X_1$; 60, 70, 80, 90, and $100^{\circ}C$), extraction time ($X_2$; 1, 2, 3, 4, and 5 hr), and ethanol concentration ($X_3$; 0, 20, 40, 60, and 80%). Soluble solid content ($Y_1$), chlorogenic acid content ($Y_2$), and coumaric acid content ($Y_3$), etc. were analyzed as the dependent variables. Estimated optimal conditions for soluble solids were an extraction temperature of $87.65^{\circ}C$, extraction time of 3.19 hr, and ethanol concentration of 42.40%. The optimal extraction conditions for chlorogenic acid were $84.30^{\circ}C$, 3.14 hr, and 47.85%, respectively. Further, those for coumaric acid were $83.45^{\circ}C$, 3.40 hr, and 45.39%, respectively. Extraction conditions for effective components of Artemisis capillaris were superimposed by response surface plots on optimization extraction condition of each dependent variable, including soluble solid, chlorogenic acid, and coumaric acid contents. As a result, superimposed extraction conditions were $80{\sim}90^{\circ}C$, 3~4 hr, and 40~50%, respectively. Under these conditions, soluble solid, chlorogenic acid, and coumaric acid contents were 1.09%, 25.66 mg%, and 20.25 mg%, respectively.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.686-692
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• 2001

The effects of extrusion on solubilization of brown rice, glutinuous rice, barley and job's tear were analyzed by response surface methodology (RSM). Solubilization of whole grains by extrusion was characterized in terms of water solubility index (WSI), concentration of water soluble polysaccharides (C) and intrinsic viscosity $([\eta])$. Considering both concentration and intrinsic viscosity, a dimensionless target parameter $([\eta])$ was also included for analysing the extrusion effects on cereal extrusion. Response surface methodology analysis showed that the moisture content was the most significant contributor among screw speed, temperature and moisture content affecting the solubilizing phenomena of cereals processed with extrusion. Brown rice was not showed the significant relationship on $([\eta])$ because $([\eta])$ was more affected by intrinsic viscosity. The critical point of whole grains extrusion except brown rice was corresponded to screw speed of 300 rpm, moisture content of 20% and temperature of $120^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.46 no.5
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• pp.588-592
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• 2014

Under optimized condition mild pressure in combination with specific temperature for heat treatment transform the 6-gingerol into 6-shogaol. The purpose of this study was to optimize the conditions used for heat treatment under pressure for increasing 6-shogaol content in ginger (Zingiber officinale Roscoe). A central composite experimental design was used to evaluate the effects of application temperature ($70-130^{\circ}C$) and temperature-holding time (95-265 min) on the transformation of 6-shogaol. The experimental values were shown to be in significantly good agreement with the predicted values (adjusted determination coefficient, $R^2{_{Adj}}=0.9857$). 6-Shogaol content increased as the application temperature and temperature-holding time increased. By analyzing the response surface plots, the optimum conditions of heat treatment (temperature and time) for increasing 6-shogaol content were found to be $127^{\circ}C$ and 109 min, respectively. Under these optimal conditions, the predicted 6-shogaol content was 3.98 mg/g dried ginger. The adequacy of the model equation for predicting the optimum response values was effectively verified by the validation data.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.4
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• pp.570-576
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• 2014

Response surface methodology (RSM) was applied to optimize the microwave-assisted extraction (MAE) conditions for electron-donating ability, total phenol content, and total flavonoid content of Ligustrum lucidum Aiton. Ligustrum lucidum Aiton from different regions was tested, and Ligustrum lucidum Aiton from Haenam was chosen due to its higher total phenolic content, total flavonoid content, DPPH radical scavenging activity and ABTS radical scavenging activity compared to the other samples. Central composite design was used to optimize extraction of Ligustrum lucidum Aiton from Haenam as well as determine the effects of extraction temperature ($X_1$) and extraction time ($X_2$) on dependent variables ($Y_n$). Determination coefficients ($R^2$) of the regression equations for dependent variables ranged from 0.8858 to 0.9517. The optimum points were $131.68^{\circ}C$ for extraction temperature and 5.49 min for extraction time. Predicted values of the optimized conditions were acceptable when compared to experimental values.