• Journal of Microbiology and Biotechnology
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• v.29 no.6
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• pp.933-943
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• 2019

Gamma-aminobutyric acid (GABA)-producing strains were isolated from four edible insects and subjected to 16S rRNA sequence analysis. Among the four GABA-producing bacteria, Enterococcus avium JS-N6B4 exhibited the highest GABA-production, while cultivation temperature, initial pH, aerobic condition, and mono-sodium glutamate (MSG) feeding were found to be the key factors affecting GABA production rate. The culture condition was optimized in terms of glucose, yeast extract, and MSG concentrations using response surface methodology (RSM). GABA production up to 16.64 g/l was obtained under the conditions of 7 g/l glucose, 45 g/l yeast extract, and 62 g/l MSG through the optimization of medium composition by RSM. Experimental GABA production was 13.68 g/l, which was close to the predicted value (16.64 g/l) calculated from the analysis of variance, and 2.79-fold higher than the production achieved with basic medium. Therefore, GABA-producing strains may help improve the GABA production in edible insects, and provide a new approach to the use of edible insects as effective food biomaterials.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.439-444
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• 2003

The major factors related in enzymatic hydrolysis of food waste using cellulolytic enzymes of Trichoderma harzianum FJ1 were optimized by response surface analysis. The factors largely affecting to the reducing sugar concentration and enzymatic saccharification rate of food waste such as substrate concentration ($X_1$, %), enzyme concentration ($X_2$, U/ml), and reaction time ($X_3$, hr) were employed. A quadratic polynominal expressing the reducing sugar (RS) concentration relating with the above factors was as follows : RS (g/l) = -17.80 + $5.04X_1$ + $51.37X_2$ + $1.21X_3$ - $0.11X_1\;^2$ - $38.86X_2\;^2$ - $0.03X_3\;^2$ + $1.64X_1X_2$ + $0.04X_1X_3$ - $0.70X_2X_3$ ($R^2$=0.9939). The maximum value of the reducing sugar concentration and saccharification rate were obtained in the conditions of substrate concentration of 18.2%, enzyme concentration of 0.78 U/ml, and reaction time of 19 hr, respectively. The predicated reducing sugar concentration and saccharification rate by the response surface methodology were 95.13 g/l and 47.27%, respectively.

• Korean journal of food and cookery science
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• v.26 no.5
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• pp.627-635
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• 2010

This study was performed to determine the optimal manufacturing conditions of cookies prepared with Hizikia fusiformis. The variables in Hizikia fusiformis cookies production were the amounts of Hizikia fusiformis powder, butter, and sugar. Six sensory characteristics were used for sensory evaluations, including color, appearance, taste, brittleness, hardness, and overall acceptability. The optimal amounts of the three variables were found to be 6.00 g for Hizikia fusiformis powder, 100.00 g for butter, and 70.00 g for sugar against flour powder 200 g, which satisfies a target sensory score (7.0/9.0) according to the response surface method. Cookies with these optimal amounts of Hizikia fusiformis powder, butter, and sugar were tasted by 114 consumers and showed a high acceptability score (7.21). Females preferred the flavor of Hizikia fusiformis significantly more than males did (p<0.05). Older consumers (${\geq}30$ years old) scored significantly higher than younger consumers (${\leq}29$ years old) in texture (p<0.05). Spread ratio and hardness scores of Hizikia fusiformis cookies were lower than those of control cookies. Color analysis results of Hizikia fusiformis cookies were significantly lower in brightness and redness, and higher in yellowness than control cookies (p<0.01).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.427-434
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• 2008

Processing of collagen from yellowfin tuna (Thunnus albacares) abdominal skins was optimized by response surface methodology and central composite design. The values of independent variables at optimal conditions were NaOH concentration: 0.5 N, NaOH treatment time: 36.2 hr, pepsin concentration: 1:4.9 ratio (0.245%, w/v), and digestion time: 48.1 hr, respectively. The collagen content estimated under optimal conditions was 33.1%, and the actual experimental collagen content was 32.3%. Physicochemical properties of collagen from yellowfin tuna abdominal skin were investigated by amino acids analysis, SDS-PAGE, FT-IR, viscosity and denaturation temperature. Amino acids content of the collagen was 21.0%. SDS-PAGE pattern of the collagen showed two different $\alpha$-chain (${\alpha}_1$- and ${\alpha}_2$- chain), $\beta$-component and $\gamma$-component. The spectrum of FT-IR of the collagen showed wavenumber at 3,434, 1,650, 1,542 and $1,235\;cm^{-1}$ representing the regions of amide A, I, II and III, respectively. Relative viscosity of the collagen decreased continuously on heating up to $32^{\circ}C$, and the rate of decrease was retarded in the temperature range of $35-50^{\circ}C$. Denaturation temperature (Td) of the collagen solution (0.06%, w/v) was $31^{\circ}C$ and was lower than calf skin collagen ($35^{\circ}C$).

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.730-736
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• 2015

Cyclotrimethylene trinitramine (RDX) is a high explosive commonly used for military applications. Submicronization of RDX particles has been a critical issue in order to alleviate the unintended and accidental stimuli toward safer and more powerful performances. The purpose of this study is to optimize experimental variables for drowning-out crystallization applied to produce submicron RDX particles. Effects of RDX concentration, anti-solvent temperature and anti-solvent mass were analyzed by the central composite rotatable design. The adjusted determination coefficient of regression model was calculated to be 0.9984 having the p-value less than 0.01. Response surface plots based on the central composite rotatable design determined the optimum conditions such as RDX concentration of 3 wt%, anti-solvent temperature of $0.2^{\circ}C$ and anti-solvent mass of 266 g. The optimum and experimental diameters of RDX particles were measured to be $0.53{\mu}m$ and $0.53{\mu}m$, respectively. The regression model satisfactorily predicts the average diameter of RDX particles prepared by drowning-out crystallization. Structure of RDX crystals was found to be ${\alpha}$-form by X-ray diffraction analysis and FT-IR spectroscopy.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.453-456
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• 2002

The production conditions of cellulolytic enzymes by Trichoderma sp. FJ1, were optimized using response surface analysis. The culture factors which largely affected to the production of enzymes such as cultivation time, carbon source concentration, nitrogen source concentration, and composition ratio of carbon sources were employed. Optimized conditions of the factors above to each cellulolytic enzyme production was as follow: CMCase production was obtained in the conditions of cultivation time of 5.4 days, 3.5% of carbon source concentration, 0.6% of nitrogen source concentration, and 52:48 (avicel:CMC) of composition ratio of carbon sources, respectively, xylanase appeared in the conditions of 5.3 day, 3.5%, 0.8%, and 54:46, respectively, and ${\beta}-glucosidase$ were 7.0 day, 5.0%, 1.0%, and 83:17, respectively, and avicelase were 6.5 day, 4.0%, 0.9%, and 64:36, respectively. The activities of CMCase, xylanase, ${\beta}-glucosidase$, and avicelase predicted by the response surface methodology were 33.5, 52.6, 2.88, and 1.84 U/ml, respectively, and ${\beta}-glucosidase$ was enhanced up to 74% compared to that obtained in the experimental conditions.

• Applied Chemistry for Engineering
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• v.31 no.2
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• pp.147-152
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• 2020

In this study, we dedicated to optimize the process for a reactive diluent for epoxy resin of improved chemical resistance by using cardanol, a component of natural oil of cashew nut shell liquid (CNSL). The central composite design (CCD) model of response surface methodology (RSM) was used for the optimization. The quantitative factors for CCD-RSM were the cardanol/ECH mole ratio, reaction time, and reaction temperature. The yield, epoxy equivalent, and viscosity were selected as response values. Basic experiments were performed to design the reaction surface analysis. The ranges of quantitative factors were determined as 2~4, 4~8 h, and 100~140 ℃ for the cardanol/ECH reaction mole ratio, reaction time, and reaction temperature, respectively. From the result of CCD-RSM, the optimum conditions were determined as 3.33, 6.18 h, and 120 ℃ for the cardanol/ECH reaction mole ratio, reaction time, and reaction temperature, respectively. At these conditions, the yield, epoxy equivalence, and viscosity were estimated as 100%, 429.89 g/eq., and 41.65 cP, respectively. In addition, the experimental results show that the error rate was less than 0.3%, demonstrating the validity of optimization.

• Journal of Nutrition and Health
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• v.47 no.1
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• pp.12-22
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• 2014

Purpose: This study was conducted to establish the production conditions through optimization of the production process of beverages using Aspergillus oryzae CF1001, and to analyze volatile compounds and antidiabetic activity. Methods: The optimum condition was selected using the response surface methodology (RSM), through a regression analysis with the following independent variables gelatinization temperature (GT, $X_1$), saccharogenic time (ST, $X_2$), and dependent variable; ${\Delta}E$ value (y). The condition with the lowest ${\Delta}E$ value occurred with combined 45 min ST and $50^{\circ}C$ GT. The volatile compounds were analyzed quantitatively by GC-MS. Results: Assessment of antidiabetic activity of saccharogenic mixed grain beverage (SMGB) was determined by measurement of ${\alpha}$-glucosidase inhibition activity, and glucose uptake activity and glucose metabolic protein expression by reverse transcriptase polymerase chain reaction (RT-PCR) and western blot analysis. Results of volatile compounds analysis, 62 kinds of volatile compounds were detected in SMGB. Palmitic acid (9.534% ratio), benzaldehyde (8.948% ratio), benzyl ethyl ether (8.792% ratio), ethyl alcohol (8.35% ratio), and 2-amyl furan (4.826% ratio) were abundant in SMGB. We confirmed that ${\alpha}$-glucosidase inhibition activity, glucose uptake activity, and glucose-metabolic proteins were upregulated by SMGB treatment with concentration dependent manner. Conclusion: Saccharogenic mixed grain beverage (SMGB) showed potential antidiabetic activity. Further studies will be needed in order to improve the taste and functionality of SMGB.

• Culinary science and hospitality research
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• v.22 no.2
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• pp.13-28
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• 2016

This study performed quantitative analysis of isoflavone glycoside contents on Buseoktae, Daewon, Wooram beans and cheonggukjang made of Buseoktae beans from the LC/MS/MS. Also, the experiment carried out by means of RSM(response surface methodology), which included 10 experimental points for the two independent variables addition(40, 55, 70 g) and time(2, 3, 4 min) from the beginning point to boil of cheonggukjang. These were optimized using a Face-centered central composite design. Daidzein contents were $212.16{\mu}g/mL$ in Buseoktae, $212.21{\mu}g/mL$ in daewon, $158.54{\mu}g/mL$ in wooram beans. Genistein contents were $318.84{\mu}g/mL$ in Buseoktae, $310.50{\mu}g/mL$ in daewon, $262.71{\mu}g/mL$ in wooram beans. Total isoflavone contents were $532.50{\mu}g/mL$ in Buseoktae, $524.19{\mu}g/mL$ in Daewon, $422.71{\mu}g/mL$ in Wooram beans. Isoflavone contents of Buseoktae and Daewon were quite similar, relatively contents of Wooram beans were low. Total isoflavone contents of Buseoktae cheonggukjang (for business use) was $430.10{\mu}g/mL$ in A ($32^{\circ}C$, 96 h fermentation), $460.09{\mu}g/mL$ in B ($36{\sim}40^{\circ}C$, 30 h fermentation), $417.46{\mu}g/mL$ in C cheonggukjang($36{\sim}38^{\circ}C$, 72 h fermentation), B cheonggukjang was just a bit more than A, C cheonggukjang. The estimated response surfaces confirmed that the amount and time had significant effects on taste. The optimum condition of Buseoktae cheonggukjang taste was predicted to be 55.20 g addition at 2.92 min.

• Food Science and Preservation
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• v.16 no.4
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• pp.472-481
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• 2009

Response surface methodology (RSM) is frequently used for optimization studies. In the present work, RSM was used to determine the antimicrobial activitiesof grapefruit seed extract (GFSE) and a lactic acid mixture (LA) against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella typhimurium, Pseudomonas fluorescens, and Vibrio parahaemolyticus. A central composite design was used to investigate the effects of independent variables on dependent parameters. One set of antimicrobial preparations included mixtures of 1% (w/w) GFSE and 10% (w/w) LA, in which the relative proportions of component antimicrobials varied between 0 and 100%. In further experiments, the relative proportions were between 20% and 100%. Antimicrobial effects against various microorganisms were mathematically encoded for analysis. The codes are given in parentheses after the bacterial names, and were S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$). The optimum antimicrobial activity of the 1% (w/w) GFSE:10% (w/w) LA mixture against each microorganism was obtained by superimposing contour plots ofantimicrobial activities on measures of response obtained under various conditions. The optimum rangesfor maximum antimicrobial activity of a mixture with a ratio of 1:10 (by weight) GFSE and LA were 35.73:64.27 and 56.58:43.42 (v/v), and the optimum mixture ratio was 51.70-100%. Under the tested conditions (a ratio of 1% [w/w] GFSE to 10% [w/w] LA of 40:60, and a concentration of 1% [w/w] GFSE and 10% [w/w] LA, 70% of the highest value tested), and within optimum antimicrobial activity ranges, the antimicrobial activities of the 1% (w/w) GFSE:10% (w/w) LA mixture against S. aureus ($Y_1$), B. cereus ($Y_2$), E. coli ($Y_3$), S. typhimurium ($Y_4$), P. fluorescens ($Y_5$), and V. parahaemolyticus ($Y_6$) were 24.55, 25.22, 20.20, 22.49, 23.89, and 28.04 mm, respectively. The predicted values at optimum conditions were similar to experimental values.