• Food Science and Preservation
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• v.13 no.6
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• pp.732-739
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• 2006

This study was performed to investigate the changes in quality properties of extract from roasted Pleurotus eryngii by microwave-assisted extraction (MAE). MAE was carried out under different conditions including ethanol concentration, extraction time and microwave power. Total phenolics compound contents, electron donating ability (EDA) and nitrite-scavenging ability at pH 1.2 were high at 50% ethanol concentration. Superoxide dismutase (SOD)-like activity was high at 75% ethanol concentration. Soluble solid and total phenolics compound content decreased as extending extraction time up to 7 min. EDA decreased as increased extraction time. SOD-like activity and nitrite-scavenging ability were not significantly different. The highest soluble solid content, total phenolics compound content and EDA were obtained at 100 W extraction of microwave power. SOD-like activity was high at 25 W. But microwave power did not significantly affect the nitrite-scavenging ability.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2687-2690
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• 2009

Due to the importance of isoflavone content in soybean extracts, the microwave-assisted process (MAP) was compared to the conventional extraction methods. For comparison of the three methods, all extraction parameters (solvent, sample to solvent ratio, temperature, etc.) were kept the same; the microwave extractor was operated at 187.5 W with an emission frequency of 2450 MHz under atmospheric pressure conditions and the extractions were carried out at 75 ${^{\circ}C}$ for 3 min while the conventional reflux was at 75 ${^{\circ}C}$ for 3 h. Total yield and crude isoflavone content were determined by ultraviolet spectrophotometric and compared with the three methods. Results indicated that the MAP was comparable to the conventional method in its capability to extract target compounds without causing any degradation; in addition it dramatically reduced the extraction time from 3 h to a few minutes, suggesting that it can be an alternative technique to the time-consuming conventional reflux method.

• Food Science and Preservation
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• v.7 no.1
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• pp.74-79
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• 2000

Water and ethanol extracts of fresh red peppers were obtained by two methods, conventional extraction (CE) and microwave-assiated extraction (MAE), under different extraction conditions. Red pepper oleoresins extracted by CE and MAE were examined in oleoresin yield and physiological activities. The proper extraction time of MAE was about 5 minutes, whereas that of CE was 2 hours. therefore extraction time was decreased drastically by MAE but there was no significance in oleolesin yields. the electron donating abilities also showed negligible difference between two extracts obtained by CE and MAE, and 80% level in all extracts . the nitrite scavenging effect was reduced by increased of ph , and showed a high elimination effect over 85% at ph 1.2. All extracts had a high tyrosinase inhibitory effects of 100%. The angiotensin I-conventing enzyme effect showed higher activity with over 80% in MAE than 70% level in CE. the capsanthin was extracted with ethanol and was 11.4 and 12.9 ${\mu}$moles per 1 g of fresh red pepper by CE and MAE, respectively.

• Food Science and Preservation
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• v.9 no.4
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• pp.385-390
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• 2002

Functional activities of Lyophyllum ulmarium microwave-assisted extracts under different conditions including electron donating ability, tyrosinase inhibition activity and nitrite scavenging effect were examined. Total polyphenol content increased as increasing microwave power up to 90 W in the water extracts. Electron donating ability increased with microwave power up to 90 W in 50% ethanol extract and 99% ethanol extract. Tyrosinase inhibition activity and nitrite scavenging effect in the extract increased as microwave power increased during extraction. Total polyphenol content increased as extending extraction time up to 5 min in the water extract. But the highest electron donating ability and tyrosinase inhibition activity was obtained after 10 min extraction. Significantly higher total polyphenol content and electron donating ability were found in the water extract whereas greater tyrosinase inhibition activity and nitrite scavenging effect were observed in 99% ethanol extract. The maxium nitrite scavenging effect was found at pH 1.2 and decreased as pH increased.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1013-1017
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• 2002

Functional activities of Flammulina velutipes extract including electron donating ability, nitrite-scavenging effect, and tyrosinase inhibition activity was examined. Extraction were carried out by microwave-assisted extraction (MAE) under different conditions including solvent and microwave power. Tyrosinase inhibition activity and nitrite-scavenging effect increased as microwave power increased during extraction. Total phenol content and electron-donating ability reached maximum at the microwave power of 90 W. Total polyphenol content and electron-donating ability increased as extraction time extended up to 15 min, with the highest tyrosinase inhibition obtained after 5 min extraction. Significantly higher tyrosinase inhibition activity was found in 99% ethanol extract, whereas greater nitrite-scavenging effect was observed in the water extract. The maximum nitrite-scavenging effect was found at pH 1.2 and decreased as pH increased.

• Food Science and Preservation
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• v.18 no.4
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• pp.546-551
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• 2011

Response surface methodology (RSM) was used for the microwave-assisted extraction (MAE) of the effective components of grape seed, such as its antioxidative and nitrite-scavenging abilities. Microwave power (2,450 MHz, 0-160W), ethanol concentration (0-100%), and MAE time (1-5 min) were used as independent variables (Xi) for the central composite design to yield 16 different MAE conditions. The optimum MAE conditions were predicted for the dependent variables of the extracts, such as the total phenolic content ($Y_1$) antioxidative ability ($Y_2$), and nitrite-scavenging ability ($Y_3$), depending on different microwave powers, ethanol concentrations, and MAE times. The determination coefficients ($R^2$) of the regression equations for the dependent variables ranged from 0.8024 to 0.9498. The maximal values of each dependent variable were predicted at different MAE conditions, as follows: 3.19% total phenolic content at 142.32W, 44.30% ethanol, and 4.36 min, and 1.22 antioxidative ability at 84.44W, 56.60% ethanol, and 3.28 min. More than 99.5% nitrite-scavenging ability was predicted at pH 1.2-3.0, 30.80-106.58W, 49.32-55.18% ethanol, and 3.72-4.58min, respectively. The results indicated that the total phenolic content and anti oxidative ability showed a higher correlation with each other in that they were more influenced by microwave power than by the other variables, while the nitrite-scavenging ability was largely influenced by the ethanol concentration.

• Food Science and Preservation
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• v.7 no.3
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• pp.273-277
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• 2000

Some fundamental conditions were investigated in microwave-assited extraction (MAE) for oleoresin from Chinese dried ginger. The fifty watts of microwave energy(2,450 MHz), 60 mesh in particle size and 1:10 (g/mL) ratio of sample to solvent were the optimum conditions. Lower yield of soluble oleoresins was obtained at higher concentrations of ethanol. Radical scavenging ability was highest in extracts by using 25% of ethanol. Total phenolics in extracts were remarkably increased at above 50% of ethanol concentration. Overall yield of oleoresin components increased in proportional to extraction time up to 7 min. Based on the above results, it is indicated that ethanol concentration is a critical parameter in MAE.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.3
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• pp.348-354
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• 2007

Extraction characteristics of ginger (Zingiber officinale) and the functional properties of the corresponding extracts were monitored by the response surface methodology (RSM). The maximum extraction yield of 38.83% was obtained under the specific extraction conditions, such as microwave power of 126.68 W, ethanol concentration of 53.39% and extraction time of 8.15 min. The maximum electron donating ability (EDA) was found as 77.92% at the conditions of 58.25 W microwave power, 91.87% ethanol concentration and 5.54 min extraction time. The maximum inhibitory effect on tyrosinase was 79.39% at 106.08 W, 2.06% and 5.61 min. The maximum polyphenol content was 105.59% under the extraction conditions of 81.82 W, 99.52% and 4.06 min. Based on superimposition of four dimensional RSM with respect to extraction yield and electron donating ability and polyphenol content obtained under the various extraction conditions, the optimum ranges of extraction conditions were found to be microwave power of $0{\sim}80\;W$, ethanol concentration of $0{\sim}40%$ and extraction time of $3{\sim}7$ min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.464-469
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• 2015

Response surface methodology (RSM) was used to monitor extraction characteristics of extracts from Sarcodon aspratus. Based on a central composite design, independent variables were microwave power (30~150 W), ethanol concentration (0~100%), and extraction time (1~9 min). Dependent variables were yield, electron-donating ability, total phenol contents, and SOD-like activity. Coefficients of determination ($R^2$) for dependent variables ranged from 0.80 at 0.97. The maximum extraction yield was 50.28% under conditions of 125.1 W microwave power, 18.67% ethanolic concentration, and 7.06 min extraction time. The maximum extraction electron-donating ability was 22.14% under conditions of 31.09 W, 45.76%, and 4.32 min. The maximum extraction total polyphenol content was 30.54 mg tannic acid equivalent/g at 122.54 W, 48.05%, and 8.36 min. The maximum extraction SOD-like activity was 33.44% at 121.17 W, 47.42%, and 8.41 min. Based on superimposition of four dimensional RSM with respect to extraction yield, electron-donating ability, total polyphenol content, and SOD-like activity obtained under various extraction conditions, optimum ranges of extraction conditions were found to be microwave power of 78~88 W, ethanol concentration of 39~57%, and extraction time of 3.5~9 min.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.1
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• pp.105-110
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• 2007

Extraction characteristics of onion (Allium cepa) and the functional properties of corresponding extracts were monitored by the response surface methodology (RSM). The maximum extraction yield of 44.02% was obtained under the specific extraction conditions, such as microwave power of 143.13 W, ethanol concentration of 61.77% and extraction time of 3.39 min. The maximum electron donating ability (EDA) was found as 45.85% at the conditions of 143.55 W microwave power, 27.52% ethanol concentration and 4.86 min extraction time. The maximum inhibitory effect on tyrosinase was 65.40% at 132.29 W, 36.47% and 7.62 min. The maximum superoxide dismutase (SOD)-like activity was 69.84% under the extraction conditions of 99.41 W, 8.47% and 7.13 min. Based on superimposition of four dimensional RSM with respect to extraction yield, electron donating ability and SOD-like activity obtained under the various extraction conditions, the optimum ranges of extraction conditions were found to be microwave power of 0$\sim$120 W, ethanol concentration of 70$\sim$80% and extraction time of 2$\sim$10 min.