• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.667-674
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• 2013

This study was aimed to investigate the effect of microwave-assisted extraction on Schizandra fruit extract dried by two different treatments: freeze-drying and hot air-drying. Two extraction parameters were measured in particular: total polyphenol content and antioxidant activity. Both values were found to increase as the microwave power increased, for both drying processes. However, the extract from the freeze-dried sample exhibited higher antioxidant activity than that from the hot air-dried samples. Additionally, the total polyphenol content and antioxidant activity of the extract from the freeze-dried samples increased with the extraction time, whereas they decreased with the extraction time in the case of the hot air-dried sample. Solvent concentration was also found to have a significant effect on total polyphenol content and antioxidant activity; the highest values for both properties were achieved at 50 and 70% ethanol concentrations, respectively. In summary, a higher total polyphenol content and antioxidant activity were observed for Schizandra fruit extracted by freeze-drying than that by hot air-drying.

• Korean Journal of Medicinal Crop Science
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• v.14 no.6
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• pp.322-328
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• 2006

Green tea is of particular source as it has been found to have strong antioxidant activities. The extracts of green tea during the commercial harvest seasons from April, 2003 to August, 2003 were compared. The purpose of this study was to determine the correlation between the polyphenol content of green teas and its antioxidant activities. The con-tent of total polyphenols was analyzed and several antioxidant testings were performed. The levels of total polyphenols were higher in the green teas (e.g. Woojeon, Sejak) harvested during very early spring and lower in the green teas harvested late(eg. Ipha, Yepcha). In particular, the free radical scavenging, the inhibition of LDL oxidation, the cytoprotective effect and the inhibition of DNA damage were correlated with the total polyphenol contents of green tea extracts harvested early spring such as Woojeon, Sejak and Jungjak. The results obtained here show that all extracts of green teas including purified green tea catechin, GTC, have strong antioxidant activities on oxidative stress in vifrθ. The variation in polyphenol content and antioxidant activities among various types of green tea by the harvesting time may provide critical information for investigators and consumers using tea in purposes of nutrition and chemoprevention.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.1
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• pp.33-40
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• 2016

This study is focused on the evaluation of growth parameters, total polyphenol content (TPC), chlorophyll content as well as the DPPH (1,1-diphenyl-2-picryhydrazyl) free radical scavenging activity of young barley seedling (YBS) affected by elicitation. Salicylic acid (SA), methyl jasmonate (MJ), amino acid liquid fertilizer (ALF) and microbial metabolism activator (MMA) were used. Elicitation was conducted for two times and various concentrations were used in this study. The result revealed that, MJ 1 ml/L treated-YBS gave the longest seedling length of 1.33 cm, followed by the ones treated with SA 1.38 mg/L and ALF 2 ml/L, respectively. ALF 3 ml/L treatment gave the highest fresh weight of 10 seedlings, followed by MJ 5 ml/L and SA 13.8 mg/L treatment with 1.56 g, 1.55 g and 1.53 g respectively. SA 138.12 mg/L elicitor treated-YBS gave the highest Chl a, Chl b content of $8.57{\mu}g/mg$ and $3.83{\mu}g/mg$, respectively while the highest carotenoid content was found in MJ ml/L treatment with $1.62{\mu}g/mg$. Among elicitor treated-YBS, SA showed better TPC. The highest TPC was found in SA 1.38 mg/L treatment with 18.82 mg/g TAE. Likewise, SA 1.38 mg/L showed the highest DPPH free radical scavenging activity among all the treatments. However, the lowest TPC was found in ALF 1ml/L treated-YBS with 9.46 mg/g TAE, which was even lower than the control (14.31 mg/g TAE).

• Preventive Nutrition and Food Science
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• v.14 no.3
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• pp.195-200
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• 2009

This study was carried out to investigate the biological activities of star anise extracts obtained from four different solvents (water, methanol, ethanol and chloroform) by measuring total polyphenol and flavonoid contents, DPPH radical scavenging, hydroxyl radical scavenging, nitrite scavenging activity and antimicrobial activity. The methanol extract showed the highest extraction yield, followed by ethanol, water and chloroform. The properties of the extracting solvents significantly affected the total polyphenol content. Methanol extracts contained more total polyphenols than any other extracts. The highest DPPH radical scavenging activity was found in methanol extract. The hydroxyl radical and nitrite scavenging activity were highest in methanol and ethanol extracts. In antimicrobial activity, water extract showed stronger activities than methanol and ethanol extract against Micrococcus luteus and Bacillus subtilis, and no inhibitory effects on Gram negative bacteria were found in all extracts at the concentration used.

• The Korean Journal of Food And Nutrition
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• v.33 no.5
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• pp.561-569
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• 2020

In this study, the antioxidative activity of Jeolpyun containing S. glauca (Bunge) Bunge powder (2%, 4%, 6%, and 8%) and extract (2%, 4%, 6%, and 8%) was evaluated based on the total polyphenol contents, electron-donating ability, scavenging of superoxide anion radical, and decomposition of hydrogen peroxide. Total polyphenol contents of Jeolpyun containing 8% S. glauca (Bunge) Bunge powder were the highest with a value of 2,280±0.00 ㎍ GAE/mL. It was observed that total polyphenol content exhibited a significant relation with concentrations at p<0.05. The electron-donating ability of Jeolpyun containing 8% S. glauca (Bunge) Bunge extract was the highest with a value of 83.93±0.69%. The electron-donating abilities revealed significant differences between concentrations (p<0.05). The superoxide radical scavenging ability of the blank was 0.01523±0.00068 and Jeolpyun containing 6% S. glauca (Bunge) Bunge powder was the highest with a value of 0.00977±0.00842. The hydrogen peroxide decomposing ability of Jeolpyun containing 0% S. glauca (Bunge) Bunge powder was -0.00377±0.0049; 8% S. glauca (Bunge) Bunge powder revealed the highest decomposing ability of -0.0476±0.0234. Hydrogen peroxide decomposing abilities revealed significant differences between concentrations (p<0.05). Jeolpyun containing S. glauca (Bunge) Bunge powder and extract demonstrated improved antioxidative activities.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.268-273
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• 2005

Changes in contents of phytochemical compounds (${\beta}$-carotene, ascorbic acid, chlorophylls, total flavonoid, total polyphenol) and hazardous factors (microbial counts, nitrate) of spinach (Spinacia oleracia L.) were investigated by conventional and microwave blanching methods. ${\beta}$-Carotene and chlorophylls contents of spinach were significantly increased by blanching, with conventional blanching resulting in higher contents than microwave blanching. In contrast, contents of ascorbic acid, total flavonoid, and total polyphenol of blanched spinach decreased, with microwave blanching resulting in higher ascorbic acid, total flavonoid, and total polyphenol contents than conventional blanching. Total plate count and total coliforms of blanched spinach significantly decreased, with conventional blanching showing less than 20-25% of microwave blanching. Nitrate content of blanched spinach also showed decreasing pattern, with decrease due to microwave blanching being lower, although not significantly, than that of conventional blanching.

• The Korean Journal of Food And Nutrition
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• v.32 no.6
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• pp.581-588
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• 2019

In this study, S. glauca (Bunge) Bunge extract was testified total polyphenol contents, electron donating ability on DPPH, and scavenging ability of superoxide anion radical and hydrogen peroxide. Total polyphenol contents of S. glauca (Bunge) Bunge extract were 7,053.30±915.93 ㎍ GAE/mL. In the fractions, fraction by ethanol was the highest content of 10,973.30±1,000.24 ㎍ GAE/mL. Fractions of ethyl acetate and water were 2,386.70±166.53 ㎍ GAE/mL, 2,413.30±41.63 ㎍ GAE/mL respectively. It was shown that total content of polyphenol according to solvent was significant relation at p<0.05. In the experiment of the electron donating ability, 70% ethanol extract and methylene chloride fraction were -246.15±24.17%, -254.01± 16.54% respectively. In case of ethyl acetate fraction, it was the highest electron donating ability to DPPH radical, 39.06±0.34%, and then water fraction of 36.71±5.55%, ethanol fraction of 29.77±2.57%, gradually. Electron donating abilities revealed significant difference (p<0.05) between the solvents. The superoxide radical scavenging ability of standard material was 0.029±0.0011; 70% ethanol extract of 0.022±0.00052, methylene chloride fraction of 0.027±0.00031, ethyl acetate fraction of 0.024±0.0011, ethanol fraction of 0.021±0.00024 and water fraction of 0.024±0.00019. Hydrogen peroxide scavenging ability of 70% ethanol extract was -0.0029±0.00040 and the others were as follow; methylene chloride fraction (-0.0042±0.00058), ethyl acetate fraction (-0.003± 0.0041), ethanol fraction (-0.0029±0.0015) and water fraction (-0.0028±0.00090).

• Journal of Sericultural and Entomological Science
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• v.53 no.2
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• pp.130-134
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• 2015

In this study, to confirm the physiological activity of the grasshopper (Oxya chinensis sinuosa) antioxidant activity, antimicrobial activity, thermal stability of the antimicrobial substance, pH stability, total polyphenol content of the adult grasshopper was measured. Antibacterial activity in accordance with the extraction solvent showed a strong antibacterial activity in a mixed solvent of ethanol for the E. coli strain. Antimicrobial activity in $40^{\circ}C$ hot air drying and a freezedried condition was the highest and there was no difference in the gender. Antibacterial substance was stable to heat and pH. Antioxidant activity of the grasshopper exhibited a high activity in the 50% and 70% ethanol extract. Total polyphenol content was the 12 ~17 mg / 100 g and there was not great difference according to the drying conditions and gender.

• Culinary science and hospitality research
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• v.24 no.1
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• pp.73-81
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• 2018

The objective of this study was to investigate their physicochemical properties and antioxidant activities of white radish teas such as pH, color value, total polyphenol contents, total flavonoids, DPPH radical scavenging activity, reducing power and sensory evaluation. They were processed by drying(AD), drying and roasting(ADR), steaming and drying(SAD), and steaming, drying, and roasting(SADR). As a result, the pH of ADR, and SADR tended to be significantly lowered and SADR was the lowest at $5.48{\pm}0.14$(p<0.001). Additionally, ADR and SADR were significantly different in color and browning value, compared to AD and SAD. There was no significant difference in reducing sugar content depending on processing methods. The total polyphenol content and total flavonoid content of the teas were significantly increase after roasting. DPPH radical scavenging activity was significantly higher in ADR and SDAR than in AD or SAD by 1.1~1.5 times(p<0.05). Compared with ADR and SADR after roasting, the sensory characteristics of AD and SAD were significantly lower than those of roasted ADAD and SAD, respectively. From the above results, it was concluded that the roasting process is a major process that affects the physicochemical quality characteristics and antioxidant activities.

• Korean Journal of Medicinal Crop Science
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• v.19 no.5
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• pp.354-361
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• 2011

In order to product dry goods of Gastrodiae Rhizoma with high quality, tubers were treated with various dry methods such as cutting, drying methods and steaming. In cutting than no cutting, they were shown shorter drying hours and lower drying yield. Drying hours in freeze drying was shorter than those of hot air and far-infrared ray. Total polyphenol content was higher in cutting than no cutting. According to steaming, it was increased in freeze drying but decreased rapidly in the other dry methods. Among all treatments, hot air dry treatment with cutting and no steaming had the highest total polyphenol content. Gastrodin and 4-hydroxybenzyl alcohol contents generally were similar or higher in cutting than no cutting. By steaming, gastrodin content in freeze drying was decreased but 4-hydroxybenzyl alcohol content was increased. But hot-air and infrared ray dry, they were shown opposite results. Gastrodin and 4-hydroxybenzyl alcohol contents showed opposite reaction to each other and were shown various response by dry methods.