Papers by Myoung-Gun Choung
The Korean Journal of Medicinal Crop Science, 2006
한국농약과학회 학술발표대회 논문집, Apr 1, 2017
Journal of the Korean Society of Food Science and Nutrition
Studies on the nutritional composition of edible insects have been conducted to evaluate them as ... more Studies on the nutritional composition of edible insects have been conducted to evaluate them as alternative protein food. However, there is limited information on the vitamin B content of these insects. Therefore, in this study, the high-performance liquid chromatography (HPLC) method was used to determine the vitamin B contents of edible insects. Thiamine, riboflavin, niacin, and pantothenic acid contents as dry matter weight base in edible insects ranged from 0.247∼6.714 mg/100 g, 0.000∼9.134 mg/100 g, 0.215∼7.919 mg/100 g, and 2.375∼22.224 mg/100 g, respectively. However, pyridoxine was not detected. The nutritional profile of edible insects and conventional protein sources (meat, dairy, and soy products) was compared for the vitamin B content. The results of this study will from part of a database to be used the publication of the 10th revision of the Korean Food Composition Table.
Molecules
The total phenolic content, anthocyanins, phenolic acids, antioxidant capacity and α-amylase inhi... more The total phenolic content, anthocyanins, phenolic acids, antioxidant capacity and α-amylase inhibitory activity of black (Aydin Siyahi), purple (Kadife Kemer) and white (Trabzon Kadife) eggplants grown in Turkey were subjected to a comparative investigation. The black cultivar exhibited the highest total phenolic (17,193 and 6552 mg gallic acid equivalent/kg fw), flavonoid (3019 and 1160 quercetin equivalent/kg fw) and anthocyanin (1686 and 6167 g delphinidin-3-O-glucoside equivalent/kg fw) contents in crude extracts of the peel and pulp. The majority of the caffeic acid was identified in the ester (2830 mg/kg fw) and ester-bound (2594 mg/kg fw) forms in the peel of ‘Kadife Kemer’ and in the glycoside form (611.9 mg/kg fw) in ‘Aydin Siyahi’, as well as in the pulp of these two eggplants. ‘Kadife Kemer’ (purple eggplant) contained the majority of the chlorogenic acid in free form (27.55 mg/kg fw), compared to ‘Aydin Siyahi’ in the ester (7.82 mg/kg fw), glycoside (294.1 mg/kg dw) an...
`자영`은 2003년 `대서` 품종과 AG34314 계통 간의 교잡후대에서 유래되었으며, 국립식량과학원 고령지농업연구센터의 감자육종 프로그램을 거쳐 선발되었다. 2006년과 ... more `자영`은 2003년 `대서` 품종과 AG34314 계통 간의 교잡후대에서 유래되었으며, 국립식량과학원 고령지농업연구센터의 감자육종 프로그램을 거쳐 선발되었다. 2006년과 2007년 대관1-104호라는 계통명으로 지역적응시험을 수행하여 주요생육특성, 괴경특성, 수량성 및 병해특성을 검토하였으며, 2007년 `자영`으로 명명하여 국립종자관리원에 신품종으로 출원하였다. `자영` 감자는 모양이 비교적 둥글고 눈이 얕으며 껍질과 속이 모두 자주색이다. ha당 평균 수량은 37.4톤이었고 봄재배에서 가장 높은 수량성을 나타냈다. `자영`은 감자더뎅이병과 잎말림바이러스병에 높은 저항성을 나타내었으나, 역병에는 감수성이었다. 건물함량은 비교적 높은 20.3%로서 칩가공용으로도 적합하였다. 안토시아닌 함량은 가을재배에서 가장 높은 43.7 mg/100 g이었고, 작형별 평균 함량은 `자심` 품종보다 4.7배 정도 더 많았다.
Food Science and Biotechnology, 2009
The aim of this study investigated the fluctuations of 3 characters from 3 ecotypes [early ripeni... more The aim of this study investigated the fluctuations of 3 characters from 3 ecotypes [early ripening (ER), middle ripening (MR), and late ripening (LR)] of 20 Korean brown rice cultivars in different storage systems [time: 12 and 24 weeks, temperature: low (10℃) and room (25℃)]. With increase of storage time and temperature, lipoxygenase activity, and fat acidity increased, whereas germination rate was reduced. ER cultivars exhibited the highest lipoxygenase activity of 35.49±2.46 unit/㎎ protein during 24 weeks storage at 25℃, followed by LR (32.73±1.33) and MR (32.66±1.62) cultivars. The amounts of fat acidity also were observed by the same order (ER: 20.40±2.12＞LR: 19.68±1.86＞MR: 19.64±1.35 ㎎ KOH/100 g). Germination rate slightly decreased with increase of time and temperature (MR＞LR＞ER), but MR and LR cultivars showed the most significant changes (ER: 60.90±23.47%, MR: 32.66±13.95%, and LR: 32.53±5.87%). On the basis of above results, MR cultivars were evaluated the highest qualit...
The Korean Journal of Crop Science, 2004
The purpose of this experiment was to obtain informations about variation of anthocyanin content ... more The purpose of this experiment was to obtain informations about variation of anthocyanin content within black-seeded soybean testa according to cultivation and harvest time. Three varieties, Ilpumgeomjeongkong, Geomjeongkong 2, Tawonkong were tested in this experiment. Seeds were planted on April 15 (early planting), May 15 (optimum planting), and June 15 (late planting), respectively. Harvest time was R6 (full seed), R7 (physiological maturity), and R8 (harvest maturity), respectively. The content of delphinidin-3-glucoside (D3G), cyanidin-3-glucoside (C3G), petunidin-3-glucoside (Pt3G), and total anthocyanin (TA) had all increased gradually from April 15 to June 15 as well as R6 to R8. There was no varietal difference in D3G, but C3G and TA of Geomjeongkong 2 were higher than other two varieties. Pt3G was the highest Tawonkong of varieties. The value of L as anthocyanin color difference had gradually decreased from April 15 to June 15 and R6 to R8, Geomjeongkong 2 among three vari...
Korean Journal of Horticultural Science and Technology, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution No... more This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Korean Journal of Environmental Agriculture, 2018
BACKGROUND: This experiment was conducted to establish a simultaneous analysis method for 7 kinds... more BACKGROUND: This experiment was conducted to establish a simultaneous analysis method for 7 kinds of herbicides in 3 different classes having similar physicochemical property as diphenyl ether(bifenox and oxyfluorfen), dinitroaniline (ethalfluralin and trifluralin), and chloroacetamide (metolachlor, pretilachlor, and thenylchlor) in crops using GC-ECD/MS. METHODS AND RESULTS: All the 7 pesticide residues were extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice and soybean. The extract was diluted with saline water and directly partitioned into n-hexane/dichloromethane(80/20, v/v) to remove polar co-extractives in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. The analytes were separated and quantitated by GLC with ECD using a DB-1 capillary column. Accuracy and precision of the proposed method was validated by the recovery experiment on every crop samples fortified with bifenox, ethalfluralin, metolachlor, oxyfluorfen, pretilachlor, thenylchlor, and trifluralin at 3 concentration levels per crop in each triplication. CONCLUSION: Mean recoveries of the 7 pesticide residues ranged from 75.7 to 114.8% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of the analytes were 0.004 (etahlfluralin and trifluralin), 0.008 (metolachlor and pretilachlor), 0.006 (thenylchlor), 0.002 (oxyfluorfen), and 0.02 (bifenox) mg/kg as verified by the
Korean Journal of Environmental Agriculture, 2018
BACKGROUND: An analytical method was developed using HPLC-UVD/MS to precisely determine the resid... more BACKGROUND: An analytical method was developed using HPLC-UVD/MS to precisely determine the residue of flusulfamide, a benzenesulfonamide fungicide used to inhibit spore germination. METHODS AND RESULTS: Flusulfamide residue was extracted with acetone from representative samples of five raw products which comprised apple, green pepper, Kimchi cabbage, hulled rice, and soybean. The extract was diluted with large volume of saline water and directly partitioned into dichloromethane to remove polar co-extractives in the aqueous phase. For the hulled rice and soybean samples, n-hexane/acetonitrile partition was additionally employed to remove non-polar lipids. The extract was finally purified by optimized Florisil column chromatography. On an octadecylsilyl column in HPLC, flusulfamide was successfully separated from co-extractives of sample, and sensitively quantitated by ultraviolet absorption at 280 nm with no interference. Accuracy and precision of the proposed method was validated by the recovery experiment on every crop sample fortified with flusulfamide at 3 concentration levels per crop in each triplication. CONCLUSION: Mean recoveries ranged from 82.3 to 98.2% in five representative agricultural commodities. The coefficients of variation were all less than 10%, irrespective of sample types and fortification levels. Limit of quantitation (LOQ) of flusulfamide was 0.02 mg/kg as verified by the recovery experiment. A confirmatory method using LC/MS with selected-ion monitoring technique was also provided to clearly identify the suspected residue.
Preventive Nutrition and Food Science, 2008
Hwangtae, dried Alaska pollack, is a major storage product in the fish processing industry. Hwang... more Hwangtae, dried Alaska pollack, is a major storage product in the fish processing industry. Hwangtae is prepared by removing the internal organs and drying outdoors during the cold witner months by allowing it to thaw during the daytime and re-freeze at night under sub-zero (-10 o C) conditions and gradually dry from December until the next April for around 5 months from Myungtae. In this study, ground Hwangtae was hydrolyzed using two proteolytic enzymes (pepsin and alcalase) which produced five soluble active peptides from Hwangtae (yellowish dried Pollack, Theragra chalcogramma) protein. Two different peptides with strong antioxidative activity were isolated from the hydrolysate using consecutive chromatographic methods of Sephadex G-25 gel, ion-exchange chromatography on a Sepharose-Sephadex C-25 gel, and high-performance liquid chromatography. The isolated peptides, APO1 and APO2, were composed of 16 and 13 amino acid residues, respectively. Both peptides contained a Gly residue at the C-terminus and the repeating motif Gly-Pro-Hyp. The peptide with a molecular weight less than 1,000 Daltons (APACE) obtained from enzymatic hydrolysates of Hwangtae exhibited the highest ACE inhibitory activity. The APACE peptides was composed of 4 amino acid residues (Gly-Leu-Leu-Pro). These results suggest that Hwangtae hydrolysates could be a good source of peptides with ACE inhibitory activity. Biochemical analysis indicated that two 70 kDa peptides (APG1 and APG2) isolated from the hydrolysate had gelatinoytic activity, which was shown to be a calcium dependent protease type as showed by gelatin SDS PAGE.
Korean Journal of Environmental Agriculture, 2015
BACKGROUND: An analytical method was developed using GC-ECD/MS to precisely determine the residue... more BACKGROUND: An analytical method was developed using GC-ECD/MS to precisely determine the residue of fipronil, a phenylpyrazole insecticide used to control a wide range of foliar and soil-borne pests. METHOD AND RESULTS: Fipronil residue was extracted with acetone from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and fipronil was partitioned into n-hexane/dichloromethane (20/80, v/v) to remove polar co-extractives in the aqueous phase. Florisil column chromatography was additionally employed for final purification of the extract. Fipronil was separated and quantitated by GC-ECD using a DB-17 capillary column. Accuracy of the proposed method was validated by the recovery from crop samples fortified with fipronil at 3 levels per crop in each triplication. CONCLUSION: Mean recoveries ranged from 86.6% to 106.0% in five representative agricultural commodities. The coefficients of variation were less than 10%. Limit of quantitation of fipronil was 0.004 mg/kg as verified by the recovery experiment. A confirmatory technique using GC/MS with selected-ion monitoring was also provided to clearly identify the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of fipronil in agricultural commodities.
The Korean Journal of Pesticide Science, 2015
Quintozene, pentachloronitrobenzene (PCNB) is a contact fungicide for control of soilborne phytop... more Quintozene, pentachloronitrobenzene (PCNB) is a contact fungicide for control of soilborne phytopathogenic fungi during cultivation of diverse crops. It was introduced to agricultural use around 1930's as a substitute for mercurial disinfectants. Although quintozene had been first registered in Korea on 1969. However, now it was banned to use due to its high residue levels in selected harvest products. Also, high possibility is expected that the residue may be contained in imported agricultural commodities as it is still used widely over the world. Therefore, this study was conducted to establish a determination method for quintozene residue in crops using GC/ECD/MS. Quintozene residue was extracted with acetonitrile from representative samples of five raw products which comprised hulled rice, soybean, Kimchi cabbage, green pepper, and apple. The extract was diluted with saline water, and n-hexane partition was followed to recover quintozene from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The quintozene was quantitated by GLC with ECD, using a DB-1 capillary column. The crops were fortified with quintozene at 3 levels per crop. Mean recoveries ranged from 79.9% to 102.7% in five representative agricultural commodities. The coefficients of variation were less than 4.3%. Quantitative limit of quintozene was 0.004 mg/kg in representative five crop samples. A GC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of quintozene in agricultural commodities.
This study was carried out to investigate the microclimate (photosynthetically active radiation a... more This study was carried out to investigate the microclimate (photosynthetically active radiation and temperature) response to different shading materials(shade plate, and polyethylene net) on Korean ginseng(Panax ginseng C.A. Meyer) bed. Photosynthetically active radiation(PAR) under polyethylene net was approximately 24 ～ 30% higher than that under shade plate on sunny day. Also, PAR was remarkably decreased from the front to the rear rows of ginseng beds. Temperature under polyethylene net was higher than that of shade plate. Internal temperature under polyethylene net was 1.9 ～ 3.1% higher than that under shade plate at the different rows of ginseng bed. Mean of total daily temperature under polyethylene net was higher at the rear rows than at the front rows, while that under shade plate was higher at the front rows than at the rear row of ginseng bed. Mean of total daily temperature on sunny days(April 15 and May 17) was 7.3% lower under shade plate than above outside but, polyethylene net was 0.7% high, while that on cloudy days(April 11 and May 15) was 1.6% higher under polyethylene net than above outside, but shade plate was 0.7% low. Also, overall mean of total daily temperature under polyethylene net was 7.0, 7.8, and 8.8 % on sunny day(April 15 and May 17), and 1.7, 1.6, and 3.5% on cloudy day(April 11 and May 15) higher than that under shade plate, respectively. The SPAD values of 6 years old ginseng at two point(front, center) in bed under shade plate showed the highest value, and the lowest under polyethylene net. The SPAD of 6 years old ginseng at rear in bed was not statistically significant under two shading materials.
This study was conducted to establish the standard of quality evaluation in Korean cultivated peo... more This study was conducted to establish the standard of quality evaluation in Korean cultivated peony root(Paeoniae Radix). The diameter of fresh root and the concentrations of paeoniflorin, abliflorin and five phenolic compounds at different root ages in Euisung cultivar were investigated. The diameters of fresh root were 5.5mm, 10.3mm, 15.6mm and 19.1mm in one-year, two-year, three-year and four-year-old, respectively. It was also found that the diameter of fresh root was uniformly increased with the increase of root age. The concentrations of paeoniflorin, albiflorin, (+) -catechin and benzoic acid in one-year-old peony root(6.44%, 1.55%, 0.80% and 0.36%, respectively) were higher than those in three-(3.49%, 0.62%, 0.43% and 0.26%) or four-year-old(3.28%, 0.47%, 0.34% and 0.20%). The concentrations of gallic acid, (-) -epicatechin and (+) -taxiforin were higher in three- (0.26%, 0.09% and 0.26%, respectively) or four-year-old (0.26%, 0.10% and 0.29%) than those in one-year-old (0.25 %, 0.08 % and 0.23 %) by contraries. Excepting (-) -epicatecin, the concentrations of paeoniflorin, albiflorin and four phenolic compounds in the root of unremoved cork layer were higher than those in the root of removed cork layer.
Comparative analysis of paeoniflorin, albiflorin and phenolic compound contents as bioactive comp... more Comparative analysis of paeoniflorin, albiflorin and phenolic compound contents as bioactive components of peony was performed by Reverse Phase-High Performance Liquid Chromatography (RPHPLC) using the four- year-old peony which were different plant parts and pretreatment, such as removing or unremoving the cork layer of peony root before drying. The contents of paeoniflorin, albiflorin, (+)-taxifolin , (+)-catechin and (-)-epicatechin were the highest in rhizome part, but those of gallic acid and benzoic acid in the leaves were higher than other parts. The contents of albiflorin, gallic acid, benzoic acid and (-)-epicatechin in the cork layer were higher than in those of the core, but the contents of paeoniflorin, (+)-taxifolin and (+)-catechin in the core were higher than those in the cork layer. In general, the rhizome part of peony root has been used only propagation purpose, but this part contained high contents of bioactive component. Therefore, it is needed that medicinal application of rhizome part in peony root was firmly investigated. Also, In the use of peony root for medicinal purpose, the use of peony root with cork layer can be efficient way on the practical use of useful components and the reduction of labor for removing the cork layer.
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Papers by Myoung-Gun Choung