• The Korean Journal of Pesticide Science
• /
• v.15 no.2
• /
• pp.140-148
• /
• 2011

The official analytical method of residue pesticides in herbal medicines by KFDA cannot be applied to all of the pesticides and herbal medicines because of various active materials in herbal medicines and various physicochemical properties of pesticides. Moreover, liquid-liquid partition uses harmful solvents such as methylene chloride and is consuming a lot of time and effort. In order to improve the problems, we have studied for the availability of the analytical method applying the macroporous diatomaceous earth (MDE) column instead of liquid-liquid partition to simultaneously analyze five pesticides in two dried herbal medicines. The results showed that the recovery rates of acetamiprid and azoxystrobin in Astragalus root by GC/ECD ranged from 89.6 to 94.1%, from 86.8 to 94.4%, respectively, and those of bifenthrin, chlorfenapyr, chlorpyrifos in Cnidii Rhizoma by GC/MS ranged from 83.6 to 88.4%, from 77.4 to 83.8%, from 82.6 to 84.3%, respectively. Also, the coefficients of variation (CV) for triplication ranged from 0.5 to 1.7%. The results satisfied the criteria of residue pesticide analysis, setting 70~120% for the recovery rate and below 10% for the coefficient of variation. The improved methods are safer to residue pesticide analysts, faster and less laborious than the KFDA official method.

• Proceedings of the Polymer Society of Korea Conference
• /
• 2006.10a
• /
• pp.301-301
• /
• 2006

The physical properties of well-defined star-shape polystyrenes with high number of arms (6 to 57 arms) in good and theta solvents were studied using synchrotron X-ray scattering. The scattering profiles for multi-armed polystyrenes shown the molecular shape is changed according to increasing of number of arm. From various parameters which were obtained from scattering profiles, the molecular shape was determined more detail. As results, the molecular shape was changed from a fuzzy-ellipsoid for 6-armed PS to a fuzzy-sphere sphere for 57-armed PS according to increasing of number of arm.

• Food Science and Preservation
• /
• v.17 no.1
• /
• pp.139-144
• /
• 2010

This study was carried out to investigate potential applications of the extract of Castanopsis cuspidata var. sieboldii $N_{AKAI}$ nut as a functional food ingredient. The pH and $^{\circ}Brix$ of nut were 6.43 and 3.17, respectively. L, a and b values as Hunter's color were 83.07, 1.49 and 10.48, respectively. Total content of monosaccharide was 54.26 mg% and organic acids were composed of oxalic acid 495.37 mg%, formic acid 200.03 mg%, malic acid 93.65 mg%, citric acid 27.80 mg%, and succinic acid 16.61 mg%. Total phenolic contents in various solvent extracts were as follows: water 27.69 mg%, 75% ethanol 16.50 mg%, ethyl acetate 16.50 mg%, and methanol 10.30 mg%. The antioxidant activity ($SC_{50},\;{\mu}g/mL$) of the nut extracts by various solvents was in the order of ethyl acetate 74.88 > methanol 155.00 > n-hexane 213.33 > ethanol 249.33 > butanol 274.78 > chloroform 314.67 > 75% ethanol 848.33 > water extracts 869.67. The results indicated that the extract of C. cuspidata nut contained a potential food ingredient.

• Journal of the Korean Chemical Society
• /
• v.17 no.3
• /
• pp.174-181
• /
• 1973

Dichlorodiacetatotitanium(IV) dissolves in alcohols with chemical reaction. Such solvolytic reaction of $TiCl_2(OAc)_2$with various alcohols has been studied by means of solution NMR spectroscopy and chemical analysis of the isolated products. The reaction of $TiCl_2(OAc)_2$ with primary alcohols has shown to be a quantitative two-step ligand substitution process as shown in the following: $TiCl_2(OAc)_2+ROH{\to}TiCl_2(OAc)_2(OR)+AcOH$ $TiCl_2(OAc)_2(OR)+ROH{\to}TiCl_2(OAc)_2+AcOH$The molecular form initially soluble in organic solvents has been found to be the monosubstituted species $TiCl_2(OAc)(OR)$. Alcoholysis with t-butyl alcohol has shown remarkable differences. When the mole ratio of t-butyl alcohol to $TiCl_2(OAc)_2$ is less than 1/2, the following reaction is dominant. $TiCl_2(OAc)_2+t-ButOH{\to}TiCl_2(OAc)_2+t-ButCl$However, at higher mole ratio another substitution process resembling the first step reaction with primary alcohols is competitively accompanied. The reaction with t-butyl alcohol also differs from that with primary alcohols in that only one either of the two chloro-or acetato-ligands in $TiCl_2(OAc)_2$ is subjected to substitution.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.45 no.9
• /
• pp.1351-1357
• /
• 2016

Green tea (Camellia sinensis) seed extract (GTSE) was prepared under various pretreatment conditions and used to investigate its extraction yield and anti-yeast activity. Anti-yeast activity of GTSE from seeds with or without the coats was the same, whereas the extraction yield was slightly higher in extract from seeds without the coat. Anti-yeast activity of GTSE from seeds with different water contents or particle sizes was the same, whereas the extraction yield was highest in extract from seeds with 7.3% moisture or a smaller particle size. Anti-yeast activity of defatted green tea seed extract (DGTSE) was the same as that of GTSE. Extraction yield was higher in DGTSE from defatted seeds by the oil press machine compared to hexane extraction. Defatted green tea seed (DGTS), a by-product from the oil extraction process, is a good natural source of anti-yeast preservative. The extraction yield and anti-yeast activity of DGTSE were investigated using various extraction solvents, temperatures, and times. The results show that water was an economic extraction solvent, and anti-yeast activity of DGTSE was unstable at $90^{\circ}C$. These results suggest that water, extraction temperature of $50^{\circ}C$, and extraction time of 4 h were the most efficient for extraction of anti-yeast compounds from DGTS.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.12
• /
• pp.1793-1798
• /
• 2015

Antioxidant activities of various solvent extracts from Coriolus versicolor were investigated for their total polyphenol content, total flavonoid content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging activity. C. versicolor extracts were produced by organic solvents such as ethanol, ethyl acetate, and methanol. Total polyphenol and flavonoid contents in the ethanol and ethyl acetate extracts were higher than those in the methanol extract. DPPH radical scavenging activity of methanol extract showed the highest value of 80.3%, which was similar to that of ascorbic acid (85.5%). All extracts showed good (>90.0%) ABTS cation radical scavenging activity. The antimicrobial activities of these extracts from C. versicolor were evaluated against six strains of bacteria using the disc diffusion method. All extracts showed antimicrobial activities against all tested bacteria except Staphylococcus aureus. These results indicate that various extracts from C. versicolor could be useful as natural antioxidant and antimicrobial agents.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.10
• /
• pp.1543-1549
• /
• 2015

Black rice bran, a by-product from rice milling process, is a good natural source of anthocyanin pigment. The purpose of this study was to determine the optimum conditions for anthocyanin extraction from black rice bran as well as the stability of anthocyanin extract according to different storage temperatures. The main anthocyanin in 'Heugkwang' rice bran was identified as cyanidine-3-glucoside (C3G) by HPLC and LC-MS/MS. The yield and C3G content of black rice bran extract were investigated with various extraction solvents, temperatures, and times. The results indicate that the optimum extraction solvent, temperature, and time were 50% ethanol, $70^{\circ}C$, and 2 h, respectively. The stability of anthocyanin extract was studied during a storage period of 168 days at various temperatures ($-20^{\circ}C$, $4^{\circ}C$, and room temperature). Hunter's values (L, a, and b) of anthocyanin extract increased, whereas C3G content continuously decreased up to 168 days. Variations in Hunter's values and C3G content become larger as storage temperature increased. Anthocyanin extract from black rice bran was very stable, as C3G content after storage at all temperatures was maintained at more than 90% of initial content. These results suggest that anthocyanin extract from black rice bran may be useful as a natural food colorant.

• Journal of the Korean Chemical Society
• /
• v.33 no.6
• /
• pp.588-595
• /
• 1989

Log K, ${\Delta}$H and ${\Delta}$S for the complexation of $La^{3+},\;Ce^{3+}$ and $Eu^{3+}$with various multidentate ligand containing crown ether, diaza crown ether and diamine ether have been determined in methanol and acetonitril solutions at $25^{\circ}C$ by solution calorimetric titration method. The greater stability constant of $La^{3+}$-15C5 than those of 18C6 diaza [2.2] in methanol are discussed in terms of the size of metal ion and the ligand cavity and of metal ion solvation. The stabilities of $Ce^{3+}$ and $La^{3+}$ ion complexes with a various multidentate ligand in acetonitril are in the order of (diamine ether)<18C6<15C5$Ce^{3+}$, $La^{3+}$ and $Eu^{3+}$-diaza [2.2] complexes in acetonitril are increased with the following order: $Eu^{3+}$ < $La^{3+}$ < $Ce^{3+}$, that is increasing order of the optimum size and of the charge density of metal ion.

• Journal of Life Science
• /
• v.24 no.4
• /
• pp.386-392
• /
• 2014

Haw (Crataegus pinnatifida $B_{UNGE}$) is a medicinal plant commonly used in Korea due to its beneficial health effects. This study was performed to investigate the antioxidative activity of bioactive components from haw seed. Freeze-dried seed was processed with various solvents such as 70% methanol, 70% ethanol, a mixture of chloroform and methanol (2:1, v / v), n-butanol and ethyl acetate (EA). DPPH, reducing power, ferric reducing antioxidant power (FRAP), and ABTS radical scavenging activity decreased in this order: 70% methanol, 70% ethanol, EA, CM, n-butanol extracts. NO radical scavenging activity was high in the n-butanol extract (36.73% in 0.8 mg/ml concentration) and low in the 70% ethanol extract (24.96% in 0.8 mg/ml concentration). $OH^-$ radical scavenging activity of n-butanol extract (40.42% in 0.8 mg/ml concentration) was higher than the other extracts, but EA extract was the lowest (13.39%) at the same concentration. The results show that each extract contained various antioxidative substances and it seemed that different influence at each antioxidative activity.

• Applied Biological Chemistry
• /
• v.44 no.1
• /
• pp.12-19
• /
• 2001

The major volatiles from Allium species were found to be sulfide compounds and the ratio of sulfide to volatiles was 66.1% in garlic, 66.1% in scallion, 62.3% in green onion, 39.2% in onion, and 4.2% in chive. Trace of cyclooctasulfur was found to be present among the volatiles. The most oviposition of 17.2% occurred at diallyl sulfide and the least of 0.8% at acetylthiophene whereas the most oviposition of 43.3% occurred at ethyl alcohol if concentration was 100%. Among the organic solvents used for dilution, ethyl alcohol received the highest 52.5% of oviposition and ether the lowest of 5.9%. Furfuryl mercaptan which is also one of the volatiles, received 46.9% of oviposition. For oviposition site, D. antiqua preferred sulfides at near 1%, ethyl alcohol at high, and other volatiles at various concentrations. At 100% concentration, most volatiles except dimethyl disulfide and ethyl alcohol received less oviposition than the control which was watered sand with no volatiles added.