• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.2
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• pp.409-416
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• 1999

Microwave extraction system equipped with closed vessels was applied to confirm its capability of extracting ginseng solubles including saponin, which was monitored to optimize extraction con ditions by response surface methodology. Total yield increased with the decrease in particles size and more extraction steps. Soluble components were completely extracted by operating the system within 6 min per one step, which should be repeated by 3 or 4 times. Optimized conditions for maxi mum extraction of response variables(total yield, crude saponin) were 40~50% of ethanol concentration, about 140oC of extraction temperature, and within 6 min of the extraction time. The extraction effi ciency of total yield was dependent on the decrease of ethanol concentration, while crude saponin content was favored on the higher degree of ethanol concentration. According to the temperature guideline, below 90oC of extraction temperature, the optimal ranges of extraction conditions were predicted as 30~50% of ethanol concentration and 2.5~6.5 min of extraction time. Estimated values of total yield and crude saponin were in good agreement with experimental values.

• Korean Journal of Food Science and Technology
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• v.40 no.5
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• pp.510-515
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• 2008

Microwave energy was applied to the extraction of functional catechins from grape seed. The solvent, absolute ethanol, reached the boiling point when exposed for less than 3 min microwave treatment at 100 W. The effects of independent variables in microwave-assisted extraction (MAE), including microwave power (0-160W, $X_1$), ethanol concentration (0-100%, $X_2$) and extraction time (1-5 min, $X_3$), were investigated on each response variable ($Y_n$), and the contents of catechin and its derivatives were determined via response surface methodology, thereby allowing us to predict their optimal extraction conditions. The predicted maximal values of (+)-catechin, procyanidin $B_2$, (-)-epicatechin, and (-)-epicatechin gallate were 137.99, 72.78, 222.38, and 9.59 mg%, respectively, under different MAE conditions. The predicted extraction conditions for maximum catechin responses were as follows: 104.10 W of microwave power, 45.35% of EtOH, and 4.89 min of extraction time for (+)-catechin (137.99 mg%), 133.16 W, 46.16% and 4.49 min for procyanidin $B_2$ (72.78 mg%), 136.00 W, 41.37% and 4.39 min for (-)-epicatechin (222.38 mg%), 143.20 W, 37.51% and 1.88 min for (-)-epicatechin gallate (9.59 mg%), respectively. The contents of (+)-catechin, procyanidin 1B2 and (-)-epicatechin in MAE were similarly influenced by three independent variables, whereas (-)-epicatechin gallate was influenced less profoundly by ethanol concentration and extraction time.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.323-327
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• 2000

Microwave-assisted process (2,450MHz), which is known as a more environmental-friendly process with economic advantages than the current extraction methods, was investigated to pre-establish the extraction conditions for soluble ginseng components used for the processing of ginseng products. The extractions of soluble ginseng components showed optimum conditions, such as 60 mesh in particle size, 1 : 10 (g/mL) in the sample to solvent ratio, and less than 100 watts in energy efficiency. Under these conditions using along with 60% ethanol for 5 min, the overall yield of ginseng extracts was about 83%. Most soluble components including saponins were extracted by repeating five times of microwave-assisted extraction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.1
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• pp.1-6
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• 2006

Through the application of a microwave-assisted extraction, the aim of study was to investigate the extraction conditions for the total yield, electron donating ability, total polyphenol contents and nitrite scavenging effect from Pleurotus eryngii. This experiment was conducted under the following extraction conditions: the microwave power (60, 90, 120 W), sample to solvent ratio (1:50, 1:20, 1:10), extraction time (1, 5, 10, 15 mins), and extractant like water, $50\%$ EtOH and $99\%$ EtOH. During the increase of microwave power ranging from 60 to 120 W, the maximized effective components were obtained when the microwave power was set at 60 W. By decreasing the ratio down to 1:10 (g/mL), the extraction of effective components but not total yield was the highest at 1:10 (g/mL). As going up to 15 min, the maximum extraction of effective components was achieved at 1 min for the extraction time and was little affected at over 5 min. In conclusion, the most appropriate conditions for the extraction of effective compounds from Pleurotus eryngii were as follows: the microwave power at 60 W, 1:10 of the sample to solvent ratio, extraction time at 1 min and water as the extractant.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.3
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• pp.390-395
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• 2012

Response surface methodology was used to monitor the characteristics of Corni fructus. A maximum electron donating ability of 81.27% was obtained at 119.71 W of microwave power, 7.71% of ethanol concentration, and 4.21 min of extraction time. The maximum inhibitory effect on tyrosinase was 105.92% at 143.36 W of microwave power, 58.19% ethanol concentration, and 6.71 min of extraction time. The maximum superoxide dismutase like activity was 87.08% under the extraction conditions of 107.33 W of microwave power, 96.14% ethanol concentration, and 31.49 min of extraction time. The total polyphenol content showed a maximum of 475.86 mg% at 140.29 W of microwave power, 27.44% ethanol concentration, and 58.69 min of extraction time. Based on the superimposition of four-dimensional RSM data regarding the electron-donating ability, inhibitory effect on tyrosinase, superoxide dismutase like activity, and total polyphenol content, the optimum ranges of extraction conditions were found to be at 78~98 W of microwave power, 3~33% ethanol concentration, and 3.6~9 min of extraction time.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.365-371
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• 1999

Microwave-assisted extraction (MAE) is known as a more environmental-friendly process with economic advantages in terms of less time, less solvent, less energy and less waste than the current reflux method that is time-consuming. MAE was applied to extract three pesticides (quintozene, tolclofos-methyl and procymidone) from ginseng in a pesticide residue analysis and eliminate pesticide contaminants from ginseng prior to production of the ginseng extracts. The optimal conditions for pesticide extraction from ginseng were 50% in power (150 watts), 2 minutes, 20 mL hexane and 2.0 g sample. The results of optimal conditions were compared with those of Soxhlet method (7 hours, 150 mL hexane). The recoveries between two methods were almost same while time and amount of solvent used in MAE were significantly decreased in comparing with those in the Soxhlet methods. When the 45% ethyl alcohol as a extraction solvent was applied to eliminate pesticides from ginseng prior to the production of the ginseng extracts, it was found that 100% quintozene, 69％ tolclofos-methyl and 83% procymidone were eliminated from ginseng. The data showed that MAE may be used to eliminate pesticide contaminants in ginseng prior to making the ginseng extracts.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.379-383
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• 2008

Extraction characteristics of garlic and functional properties of corresponding extract were monitored by response surface methodology (RSM). Maximum extraction yield of 26.41% was obtained at microwave power of 146.29 W, ethanol concentration of 63.31 %, and extraction time of 5.88 min. At microwave power, ethanol concentration, and extraction time of 114.84 W, 58.83%, and 1.42 min, respectively, maximum electron-donating ability (EDA) was 72.86%. Maximum nitrite-scavenging ability was 94.62% at microwave power, ethanol concentration, and extraction time of 81.83 W, 2.65%, and 3.83 min, respectively. Superoxide dismutase (SOD) showed maximum pseudo-activity of 49.12% at microwave power of 34.23 W, ethanol concentration of 33.11 %, and extraction time of 4.40 min. Based on superimposition of 4-dimensional RSM with respect to extraction yield, electron-donating ability, nitrite-scavenging ability, and pseudo-activity of SOD, optimum ranges of extraction conditions were microwave power of 0-100 W, ethanol concentration of 40-70%, and extraction time of 2-8 min.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1022-1028
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• 2000

Aster glehni was extracted by microwave-assisted extraction(MAE) and reflux extraction(RE) methods and their extraction efficiencies were compared. A considerable reduction in extraction time was achieved by MAE. When 70% methanol, 50% methanol, 70% ethanol, or 50% ethanol was used, MAE extract contained nearly same amounts of soluble solid and total polyphenol contents as obtained by RE. The optimum MAE conditions for the extraction of Aster glehni were $120{\sim}150$ watts of microwave energy and $4{\sim}8$ minutes of extraction time. No significant changes were found in electron donating ability(EDA) over the variation of microwave energy or extraction time. The use of diluted methanol or ethanol resulted in improving extraction yield(24%), total polyphenol content(2.6%) and EDA(60%).

• Food Science and Preservation
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• v.15 no.6
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• pp.840-846
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• 2008

Microwave-assisted extraction (MAE) of grape seeds was performed under the different conditions based on a central composite design for independent variables of microwave power ($0{\sim}120\;W$), ethanol concentration ($0{\sim}100%$) and extraction time ($1{\sim}5\;min$). Response surface methodology (RSM) was used to predict the optimum extraction conditions for three dependent variables in grape seed extracts: total yield, total catechin and electron donating ability. Determination coefficients ($R^2$) of regression equations for the three dependent variables were higher than 0.9 (p < 0.01). The optimal MAE conditions to yield the maximum value of total catechin (434.16 mg%) were 122.76 W microwave power, 42.88% ethanol and 4.67 min extraction time. The superimposed contour maps for maximizing the three dependent variables indicated that the MAE condition ranges were 75150 W, 4060% ethanol and 3.55.0 min. The predicted values at the optimized conditions (6.72% total yield, 408.65 mg% total catechin, and 83.33% electron donation ability) were similar to the experimental values. The optimized MAE (112.5 W, 50% EtOH, 4.2 min) was more efficient than the conventional solvent extraction using 80% EtOH, $60^{\circ}C$ for 3h and 150 rpm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1465-1471
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• 2007

Response surface methodology (RSM) was employed to optimize extraction conditions in order to find the maximal functional properties of fluid Cheonggukjang. Based on central composite design, a study plan was established with variations of microwave power, ethanol concentration, and extraction time. Regression analysis was applied to obtain a mathematical model. The maximum inhibitory of tyrosinase activity was found as 26.75% at the conditions of 30.56W microwave power, 2.40 g/mL of ratio of solvent to sample content and 10.00 min extraction time, respectively. The maximum superoxide dismutase (SOD)-like activity was 53.23% under the extraction conditions of 108.42 W, 4.38 g/mL and 7.84 min. Based on superimposition of three dimensional RSM with respect to extraction yield, inhibitory of tyrosinase activity and SOD-like activity obtained under the various extraction conditions, the optimum ranges of extraction conditions were found to be microwave power of $55{\sim}75$ W, ratio of solvent to sample content of $2{\sim}5$ g/mL and extraction time of $3.5{\sim}15$ min, respectively.