• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.290-295
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• 2020

In this study, the optimum conditions were established for anthocyanidin extraction from sweet potato tips and tubers. The dependent variables of ethanol concentration (X1), citric acid concentration (X2), and extraction temperature (X3) were designed using a central composite design. All three variables significantly affected anthocyanidin extraction, and the influence of X1 was greater than that of X2 and X3. The highest anthocyanidin content in tips and tubers were 26.58±0.07 and 117.32±0.39 mg/100 g at 50% (X1), 0.3% (X2), and 50℃ (X3), respectively. The optimal extraction conditions for the tips were 56.10% (X1), 0.25% (X2), and 52.24℃ (X3) and tubers were 55.08% (X1), 0.30% (X2), and 53.06℃ (X3). The predicted values under optimal extraction conditions were 27.45 and 119.61 mg/100 g, and the experimental values were 27.09±0.11 and 118.72±0.67 mg/100 g, respectively. The extraction conditions were validated by comparing the predicted and actual values with those of 98.69 and 99.26%, respectively.

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.532-538
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• 2020

In this study, emulsification process were conducted to manufacture the natural sunscreen from raw materials such as shea butter, olive emulsifier wax, and green tea extract. The emulsification was optimized by using the central composite design model-response surface methodology (CCD-RSM) where the response values were established as the mean droplet size (MDS) and emulsion stability index (ESI) after 7 days in addition to UV absorbance at 300nm. The amount of emulsifier and additives and emulsification time were established as operating variables and the optimal conditions of sunscreen emulsification were accepted as 3.70, 2.47 wt.%, and 15.42 min, respectively according to the result of CCD-RSM. On the other hand, the response values were estimated as 1173.80 nm and 99.56% for MDS and ESI, respectively, after 7 days, in addition to UV absorbance at 300 nm (2.47). The average error from actual experiments was a low level as about 3.0 ± 1.5%, which is mainly due to the fact that the optimization using CCD-RSM applied in this study was in the relatively high significant level.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.113-125
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• 2017

In spite of bulk literature about the tuning of TMD, the effectiveness of TMD in reducing the seismic response of engineering structures is still in a row. This paper deals with the optimum tuning parameters of a passive TMD and simulated on MATLAB with a ten-story numerical shear building. A weighted multi-objective optimization method based on computer experiment consisting of coupled with central composite design(CCD) central composite design and response surface methodology(RSM) was applied to find out the optimum tuning parameters of TMD. After the optimization, the so-conceived TMD turns out to be optimal with respect to the specific seismic event, hence allowing for an optimum reduction in seismic response. The method was employed on above structure by assuming first the El Centro seismic input as a sort of benchmark excitation, and then additional recent strong-motion earthquakes. It is found that the RSM based weighted multi-objective optimized damper improves frequency responses and root mean square displacements of the structure without TMD by 31.6% and 82.3% under El Centro earthquake, respectively, and has an equal or higher performance than the conventionally designed dampers with respect to frequency responses and root mean square displacements and when applied to earthquakes.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.225-231
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• 2002

The physicochemical characteristics of pine nuts gruel were investigated to find the effects of processing condition during the processing. Three-dimensional response surface methodology was applied to investigate effects of ratio of water volume and pine nuts weight to rice weight and heating time on dependent variables of the physicochemical characteristics. The dependent variables in physicochemical characteristics were viscosity (cP), spreadability (cm), pH, soluble solid content (%), color, total sugar (%) and amylose content (%). The F-value of ratio of water volume and pine nuts weight to rice weight and heating time to viscosity were 8.91, 4.54 and 5.02 respectively and they are significantly different at 5% level. The F-value to spreadability were 5.44, 7.88 and 8.04 respectively and they are significantly different at 5% level. These results suggest that water volume, pine nuts weight and heating time greatly affect the viscosity and spreadability of pine nuts gruel. The processing condition also affect the soluble solid content. The changes of the processing condition did not affect the pH of pine nuts gruel. We found that the L, a, b value were affected more by ratio of water volume and pine nuts weight to rice weight than by heating time. The water volume affected more the total sugar and amylose content of pine nuts gruel than pine nuts weight and heating time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.733-739
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• 2014

To develop an effective use for poor-quality individually quick-frozen (IQF) oysters Crassostrea gigas stored for a long period, the extract conditions, quality characteristics, and optimum reaction flavoring (RF) conditions of a complex extract from these IQF oysters were investigated. The moisture, pH, and volatile basic nitrogen contents of IQF oysters stored for 18 months (18M-IQFO) were 77.9%, 6.32, and 17.9 mg/100 g, respectively. Three different kinds of extract were prepared from 18M-IQFO: a hot-water extract (HE), scrap enzymatic hydrolysate (EH), and complex extract (CE). The respective extracts contained 5.5, 8.6, and 6.6% crude protein and 281.7, 366.0, and 343.0 mg/100 g amino nitrogen, and had 811, 359, and 1,170 mL/kg extraction yields. The CE was superior to the traditional HE in terms of the extraction yield, amino-nitrogen content, and organoleptic qualities, except for the odor. To improve flavor via the Maillard reaction, the reaction system used to produce a desirable flavor comprised CE (Brix $30^{\circ}$), 0.4 M glucose, 0.4 M glycine, and 0.4 M cysteine solution (4:2:1:1, v/v). The reaction time and pH were the independent variables, and the sensory scores for baked potato odor, masking shellfish odor, and boiled meat odor were the dependent variables. The surface response methodology (RSM) analysis of the multiple responses optimization gave a reaction time of 120.6 minutes and pH 7.33 at $120^{\circ}C$. The reaction improved the flavor of CE considerably, as compared to that of the unreacted extract.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.704-711
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• 2010

Lignocellulose ($2^{nd}$ generation) is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of agriculture residuals and nonedible crops biomass, e.q., rice straw and miscanthus sinensis, because of their several superior aspects as agriculture residual and nonedible crops biomass; low lignin, high contents of carbohydrates. In this article, as the basic study of AP(Ammonia Percolation), the properties and the optium conditions of process were established, and then the overall efficiency of AP was investigated. The important independent variables for AP process were selected as ammonia concentration, reaction temperature, and reaction time. The percolation condition for maximizing the content of cellulose, the enzymatic digestibility, and the lignin removal was optimized using RSM(Response Surface Methodology). The determined optimum condition is ammonia concentration; 11.27%, reaction temperature; $157.75^{\circ}C$, and reaction time; 10.01 min. The satisfying results were obtained under this optimized condition, that is, the results are as follows: cellulose content(relative); 39.98%, lignin content(relative); 8.01%, and enzymatic digestibility; 85.89%.

• Food Science and Preservation
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• v.19 no.5
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• pp.703-711
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• 2012

This study was conducted to investigate the quality and organoleptic properties of dehydrated onions with steaming and heating. Sliced onions were treated as follows: steaming time ($X_1$, 5~25 min); drying temperature ($X_2$, $55{\sim}70^{\circ}C$) and drying time ($X_3$, 4~20 hr). All the variables were modelled and analyzed using a central composite design and response surface methodology (RSM). The coefficients ($R^2$) of the water content and water activity model induced from RSM were 0.9514 (p<0.01) and 0.9455 (p<0.01), respectively. The water content and water activity were affected by the drying temperature and time. The $R^2$ on the models of Hunter's L, a, b values were 0.9419 (p<0.05), 0.8818 (p<0.01) and 0.9360 (p<0.01), respectively. Hunter's L, a, b values were affected by the drying temperature and time, but Hunter's b value was not affected by the steaming time. In addition, the $R^2$ on the models of overall palatability was 0.8867 (p<0.05). The maximum palatability response was 5.92 when the steaming time was 13.14 min, the drying temperature was $63.11^{\circ}C$ and the drying time was 14.49 hr.

• Food Science and Preservation
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• v.23 no.6
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• pp.859-865
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• 2016

Thise study aimed to determine the optimum antioxidant extraction conditions of dried Gugija (Lycium chinensis Mill). To determine the operational parameters, including ethanol concentration ($X_1$, 0~80%) and extraction time ($X_2$, 1~5 hr), a response surface methodology was applied to monitor brown color intensity, total phenolic compounds, ABTS radical scavenging activity, and $Fe^{2+}$ chelating activity. Coefficients of determinations ($R^2$) of the models were 0.8486~0.9214 (p<0.05~0.1) in dependent parameters. Brown color intensity of Gugija extracts reached a maximum of 0.75 (OD in 420 nm) under extraction conditions of 2.88 hr in 78.10% ethanol. Total phenolic compounds reached a maximum of $2,355{\mu}g$ under extraction conditions of 4.94 hr in 30.17% ethanol. ABTS radical scavenging activity was 13.83% at 4.61 hr and 16.21% ethanol. $Fe^{2+}$ chelating activity showed a maximum of 58.54% under extraction conditions of 3.39 hr in 0.76% ethanol. Optimum extraction conditions (5 hr extraction in 15% ethanol) were obtained by superimposing the contour maps with regards to total phenolic compounds, ABTS radical scavenging activity, and $Fe^{2+}$ chelating activity of dried Gugija. Maximum values of total phenolic compounds, ABTS radical scavenging activity, and $Fe^{2+}$ chelating activity under optimum extraction condition were $2,397{\mu}g$, 15.62% and 54.78%, respectively.

• Korean journal of food and cookery science
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• v.15 no.5
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• pp.512-523
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• 1999

A purpose of this study was to figure out the best cooking conditions of salted-dried fish by a sensory evaluation on cooked salted-dried flathead. Cooking of the salted-dried fish is traditional and popular in Korea, and salted-dried flathead is a favorite with southern Korea. The raw material for the examination were a raw flathead and 3 degrees salted(2%, 4%, 6%)-dried flathead which added 3 kinds cooking treatment (steaming, boiling, baking) within three different times(5, 10 and 15 min.) respectively. The category scaled descriptive test and response surface methodology were applied for the evaluation, and the results of the evaluation were analyzed by SAS program. The result of the study were as follows : 1. For the steaming cooking, scale at 6% salt concentration and 5 minutes cooking time were the best conditions of the salted-dried flathead cooking. 2. For the boiling, 6% salt concentration and 10 minutes cooking time were the best conditions. 3. For the baking, 6% salt concentration and 10 minutes cooking time were the best conditions. 4. The baking group got higher estimations on the items of browning, cooked condition and meaty aroma than steaming and boiling group on Duncan's multiple range test. According to the result of the Duncan's test, baking is better cooking way for the salted-dried flathead.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.1
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• pp.123-136
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• 2018

The objective of this study is to propose a new methodology to fabricate a reliable engineering-scale buffer block, which shows homogeneous and uniform distribution in buffer block density, for in-situ experiments. In this study, for the first time in Korea, floating die press and CIP (Cold Isostatic Press) are applied for the manufacture of an engineering-scale bentonite buffer. The optimized condition and field applicability are also evaluated with respect to the method of manufacturing the buffer blocks. It is found that the standard deviation of the densities obtained decreases noticeably and that the average dry density increases slightly. In addition, buffer size is reduced by about 5% at the same time. Through the test production, it is indicated that the stress release phenomenon decreases after the application of the CIP method, which leads to a reduction in crack generation on the surface of the buffer blocks over time. Therefore, it is confirmed that the production of homogeneous buffer blocks on industrial scale is possible using the method suggested in this study, and that the produced blocks also meet the design conditions for dry density of buffer blocks in the AKRS (Advanced Korea Reference Disposal System of HLW).