• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.2
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• pp.182-186
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• 2006

This study was investigated on the antioxidative activity of $70\%$ ethanol extracts from lotus (Nelumbo nucifera) leaf. The extraction yields of $70\%$ ethanol extract was $8.16\%$. The extract was further fractionated subsequently by hexane, chloroform, ethyl acetate, butanol and water. Antioxidative activity was examined by electron donating ability (EDA) using DPPH, TBA value, acid value (AV), and peroxide value (POV), in comparison with commercial antioxidants. Butanol fraction showed the highest extraction yields but ethyl acetate fraction showed the highest phenol content. The ethyl acetate fraction showed the highest EDA. The antioxidative activity of ethyl acetate fraction determined by AV and POV in accelerated oxidation condition of lard was similar to that of BHA.

• Journal of Plant Biotechnology
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• v.49 no.2
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• pp.150-154
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• 2022

This study examined the antioxidant activity of ethanol extract and fraction from Castanea crenata inner shell in vitro. Antioxidant activity was evaluated through total polyphenol and flavonoid contents and DPPH radical scavenging ability using electron spin resonance (ESR). The total polyphenol contents of the 70% ethanol extract and ethyl acetate fraction were 39.76 mg GAE/g and 323.92 mg GAE/g (p < 0.05). The total polyphenol contents of the ethyl acetate fraction were higher than other fractions. Furthermore, the total flavonoid contents of ethyl acetate were higher than other fractions at 13.12 mg QE/g (p < 0.05). In DPPH radical scavenging ability measurement, the RC₅₀ value of ethyl acetate was lower than ascorbic acid at 2.27 ㎍/mL (p < 0.05). In conclusion, this result showed that the ethyl acetate fraction of Castanea crenata inner shell 70% ethanol extract has high antioxidant activity.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.638-643
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• 1998

The volatile flavor components in Takju made from mashed glutinous rice and barley rice were identified by GC and GC-MS using polar column. Twenty eight kinds of flavor compounds including 10 alcohols, 9 esters, 2 acids, 7 aldehydes were identified. At the beginning of fermentation 14 kinds of volatile components were detected and the kinds of volatile components were increased up to maximum after fermentation for 16 days. The contents of volatile components in the sample made from glutinous rice contained slightly higher than the sample made from barley rice. Ethyl alcohol, n-propyl alcohol, iso-amyl alcohol, n-hexyl alcohol, hexenyl alcohol, 2-phenylethyl alcohol, ethyl acetate, ethyl succinate, 2-phenylethyl acetate, butyic acid, benzaldehyde and 3-methoxybenzaldehyde were detected in the both of the sample throughout the fermentation process. Five kinds of aldehyde including ethyl propionate, iso-amyl acetate, ethyl caprylate and ethylphenyl acetate were detected only in the sample fermented for 16 days. The main components of the both sample were ethyl alcohol, iso-amyl alcohol, 2-phenylethyl alcohol, 2-phenylethyl acetate, hexenyl alcohol and iso-butyl alcohol. Besides ethyl acetate and benzaldehyde from glutinous rice Takju and hexenyl alcohol from barley rice Takju were found as main components.

• Membrane Journal
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• v.10 no.4
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• pp.186-191
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• 2000

The recovery of three ethyl esters (aroma model compounds; ethyl acetate, ethyl propionate. ethyl butyrate) from aqueous solutions was studied for vapor permeation with surface-modified hydrophobic alumina membrane, Although the driving force of ethyl butyrate is the highest, the ethyl butyrate concentration in permeate is lower than those of propionate and acetate. Since the solubility of aroma compounds for water is very low, phase separation occurred in permeate, and we could obtain pure ethyl esters. The experimental results showed that the porous hydrophobic alumina membrane had high selectivity and permeation flux on the ester-model compounds.

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.704-714
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• 2005

Phase separations of Poly(4-vinylphenol)(PVPh)/Ethyl Acetate and PVPh/Butyl Acetate solutions were measured using the thermal optical analysis (TOA) method. The experimental phase separation data were correlated with liquid-liquid equilibria relations based on PC-SAFT equation of state. The phase separations of these system showed the behaviors of LCST (lower critical solution temperature)-type. The measured cloud temperatures were lowered with increasing in molecular weights of polymer(PVPh), and cloud temperatures of PVPh/Ethyl Acetate solutions shifted to lower temperature regions, compared to the PVPh/Butyl Acetate solutions. Extents of cross-association between solvent molecule and polymer in the PVPh/Ethyl Acetate solutions were measured using the FT-IR spectrum analysis method, and cross-association parameters of PC-SAFT model were estimated from experimental extents of cross-association. By using the estimated cross-association parameters between PVPh and solvent molecule, binodal and spinodal curves of liquid-liquid equilibria in PVPh/Ethyl Acetate and PVPh/Butyl Acetate solutions were calculated from PC-SAFT equation of state. The calculated binodal curves of these system were shown to be well agreeable with the experimental cloud temperature curves.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.642-647
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• 2005

Lonicerae Flos was extracted with methanol and successively fractionated with petroleum ether, chloroform, ethyl acetate, and methanol to investigate their antimicrobial effects against food-borne pathogens and food spoilage bacteria using paper disc method. Ethyl acetate extracts of L. Flos showed highest antimicrobial activity against Shigella dysenteriae. Synergistic effect in inhibition was observed when L. Flos extract was mixed with Artemisa capillaris extract as compared to using each extract alone. Growth inhibition curves were determined using ethyl acetate extracts of L. Flos against Staphylococcus epidermidis and S. dysenteriae. Ethyl acetate extract of L. Flos had antimicrobial activity against S. dysenteriae at 3,000 ppm, retarding growth of S. dysenteriae up to 12 hr.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1331-1337
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• 2012

The study analyzed the total polyphenolic contents, DPPH radical scavenging activities, ABTS radical scavenging activities, reducing power levels, SOD-like activities, and tyrosinase inhibition activities of fractions from Campanula takesimana Nakai extract. Total polyphenolic content of the ethyl acetate fraction from Campanula takesimana Nakai extract was the highest. The ethyl acetate fraction of Campanula takesimana Nakai extract showed the lowest $IC_{50}$ value (0.13 mg/mL) as well as greater than 98% ABTS radical scavenging activity, which was similar to ascorbic acid. Further, reducing power was significantly higher in the ethyl acetate fraction. The SOD-like activity of edible plant was 70.56% (n-butanol fraction) and 62.27% (ethyl acetate fraction) at 1 mg/mL. Tyrosinase inhibition activity of Campanula takesimana Nakai extract was reduced to 34.77% in the n-butanol fraction and 30.85% in the ethyl acetate fraction at 5 mg/mL. These results suggest that the ethyl acetate and n-butanol fractions of Campanula takesimana Nakai extract could be applicable as food additives or cosmeceutical ingredients.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.11
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• pp.1382-1388
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• 2008

Antimicrobial activities of green tea extracts used for coarse tea were investigated by disc diffusion method using eight different bacteria. Among the green tea extracts, the 70% ethanol extract demonstrated the strongest antimicrobial activities against Vibrio parahemolyticus (V. parahemolyticus) and Staphylococcus aureus (S. aureus) and thus was further fractionated. Among these fractions, the ethyl acetate fraction showed the strongest antimicrobial activities against V. parahemolyticus, S. aureus, Bacillus subtilis (B. subtilis), and Streptococcus mutans (S. mutans). These activities exceeded that of all extracts and fractions tested in this study. Interestingly, although green tea extracts showed significant antimicrobial activity against Micrococcus luteus (M. luteus), once fractionated, the ethyl acetate fraction did not show any antimicrobial activity against M. luteus. MICs of the ethyl acetate fraction were $5\;\;{\mu}L$/disc against B. subtilis and $3\;{\mu}L$/disc against S. aureus, S. mutans and V. parahaemolyticus. 90% inhibition of B. subtilis was observed with 0.05% ethyl acetate fraction but S. mutans needed over 0.1% ethyl acetate fraction to exhibit the same inhibition as B. subtilis. Antimicrobial activities of ethyl acetate fractions were reduced around 10% by thermal treatment at $121^{\circ}C$ for 20 min. All the results suggest that the 70% ethanol extract as well as the ethyl acetate fraction from green tea used for coarse tea could be further developed into a natural antimicrobial agent.

• Korean Journal of Pharmacognosy
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• v.48 no.1
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• pp.63-69
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• 2017

Saururus chinensis (Lour.) Baill. (Saururaceae) has been used as a traditional medicine for the treatment of dysuria, leukorrhea, eczema, jaundice and ascites in Korea, China and Japan. Ethanol extract of S. chinensis was successively partitioned as methylene chloride, ethyl acetate, n-butanol and $H_2O$ soluble fractions. Among those fractions the ethyl acetate soluble fraction showed the most potent DPPH radical scavenging and superoxide quenching activities. To verify antioxidant activities of ethyl acetate fraction, we checked the activities of superoxide dismutase (SOD) and catalase, and intracellular ROS level and oxidative stress tolerance in Caenorhabditis elegans. Furthermore, to see if increased stress tolerance of worms by treating of ethyl acetate fraction was due to regulation of stress-response gene, we quantified SOD-3 expression using transgenic strain. Consequently, ethyl acetate fraction elevated SOD and catalase activities of C. elegans, and reduced intracellular ROS accumulation in a dose-dependent manner. Moreover, ethyl acetate fraction-treated CF1553 worms exhibited significantly higher SOD-3::GFP intensity.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.977-983
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• 2005

The removal characteristics of ethyl acetate and 2-butanol were investigated in a bench-scale down-flow biofilter packed with Jeju scoria medium. Various inlet concentrations and gas flow rates were tested. The adaptation times of microorganisms to the change of the influent concentration of ethyl acetate and 2-butanol gas were found to be about 3 days. At the inlet concentration of 300 ppmv and empty bed contact time (EBCT) of 15 see, the removal efficiencies of the biofilter for ethyl acetate and 2-butanol were above $99.9\%$. The maximum removal capacity of the biofilter for ethyl acetate was $316-318\;g/m^3/h$ and that for 2-butanol was $245-251\;g/m^3/h$. Overall, the removal capacity of the biofilter for ethyl acetate was $50-70\;g/m^3/h$ larger than that for 2-butanol. During the operation of 65 days, the pressure drop through the biofilter column was maintained below $13\;mmH_{2}O/m$. Although the pH in the drain water decreased from 7.2 to 5.0, the pH drop did not affect the removal of the gases. From the above results, the biofilter using Jeju scoria as a packing material seemed to very effectively treat waste gases such as ethyl acetate and 2-butanol.