• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.309-317
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• 2015

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.

• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.299-303
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• 2016

Salmonella spp. and Brucella spp. can cause considerable diseases on both humans and animals. In addition, these microorganisms cause the economic loss in animal farming and food industry. In this study, the disinfection efficacy of a disinfectant spray, composed to grapefruit seed extract, citric acid, malic acid and benzalkonium chloride, was evaluated against S. Typhimurium and B. ovis. A bactericidal efficacy test by broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test bacteria for 30 min at $4^{\circ}C$. The disinfectant and test bacteria were diluted with hard water (HW) or organic matter suspension (OM) according to treatment condition. On HW condition, the bactericidal activity of the disinfectant spray against S. Typhimurium and B. ovis was 5 and 4 fold dilutions, respectively. On OM condition, the bactericidal activity of the disinfectant spray was 2 and 1 fold dilutions against S. Typhimurium and B. ovis, respectively. As the disinfectant spray possesses bactericidal efficacy against foodborne pathogens such as S. Typhimurium and B. ovis, the disinfectant spray can be used to control the spread of bacterial diseases.

• Journal of Food Hygiene and Safety
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• v.33 no.5
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• pp.339-346
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• 2018

This study was conducted to monitor the current status of pesticide residues in a total of 297 agricultural products for raw juice from January 2017 to September 2017. Pesticide residues in samples were analyzed by multiresidue method for the determination of multiclass pesticide with an aim to detect 220 pesticides using GC/ECD, GC/NPD, TOF/MS, LC/PDA, LC/FLD, and LC/MS-MS. The analysis revealed the presence of nine pesticides in 14 samples. The detected pesticides were chlorpyrifos, cyflufenamid, chlorothalonil, pendimethalin, azoxystrobin, pyridalyl, imazalil, fludioxonil and procymidone. The kinds of detected crops were mandarin, carrot, apple, celery, chicory, orange and grape. Risk assessment evaluated human health exposure with the ratio of EDI (Estimated daily intake) to ADI (Acceptable daily intake) of pesticides detected and the range of %ADI (the ratio of EDI to ADI) values was 0.0011~6.7087% and safety level.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.35-41
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• 1998

Essential amino acid composition of seventy eight medicinal herbs marketed in Korea was analyzed of the basis of their dried weight. From the results analyzed, it was shown that Alisma orisntale (S.) J. (1,911.5 mg%), Foeniculum vulgare M. (1,090.8 mg%), Artemisia princeps P. (1,073.6 mg%) and Typha latifolia L.(956.1 mg%) contain in threonine. Alisma orisntale (S.) J. (2,523.3 mg%), Nelumo nucifera G. (1,984.7 mg%) and Foeniculum vulgare M. (1,553.8 mg%) contain in lysine. Nelumo nucifera G. (738.3 mg%), Alisma orisntale (S.) J. (635.2 mg%) and Foeniculum vulgare M. (507.7 mg%) contain in methionine. Nelumo nucifera G. (2,496.9 mg%), Alisma orisntale (S.) J. (2,295.6 mg%) and Coix lachrymajobi L. var. M. S. (2,222.5 mg%) contain in leucine. Nelumo nucifera G. (1,624.6 mg%), Alisma orisntale (S.) J. (1,432.7 mg%) and Xantnium strumarium L. (1.371.7 mg%) contain in isoleucine. Alisma orisntale (S.) J (1,791.0 mg71), Nelumo nucifera G. (1,570.6 mg%) and Xantnium strumarium L. (1,498.7 mg%) contain in phenylalanine.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.303-310
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• 2002

An optimization for fermentation processes to make lactic acid juice with extracts from apples, carrots, celery, watercress, jujube and lycii (3 : 3 : 1 : 1/2 : 1 : 1/2) using co-cultures of Leuconostoc mesenteroides, Lactococcus lactis and Lactobacillus cellobiosus isolated from Dongchimi had been investigated on the emphasis of composition of sugars and sodium chloride at various temperatures. The concentration of sugars less than 25% and salt less than 0.8% did not affect remarkably the cell growth of lactic acid bacteria and acid formation during fermentation. The fermenting juice showed increases in the population of lactic acid bacteria and acidity, and decreases in population of coliform bacteria and sugar concentration with high cultural temperature. At $25^{\circ}C$ viscous substance was not formed as it had at $15^{\circ}C$. The optimum composition, based on the sensory evaluation, was determined to be oligosaccharide and 0.2% for sodium chloride. It took 3 days to produce the most preferable juice of pH 3.62 at $25^{\circ}C$. At the optimal state the fermented juice showed viable cell counts (cfu/mL) of exponential numbers 8 for lactic acid bacteria and 4 for yeast. Coliform bacteria which had been $5.6{\times}10^2\;cfu/mL$ at the beginning of fermentation were not detected.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.151-156
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• 2002

Five kinds of red wine from three different grape varieties, Gerbong (G), Campbell (C), Moru (M), Gerbong+Moru (70:30, GM) and Gerbong+Campbell (70:30, GC), were prepared. Their chemical and microbiological changes were monitored during alcohol fermentation and aging. The changes of pH, brix and total acidity were $3.2{\sim}3.6,\;17.9{\sim}6.0$ and $2.4{\sim}4.6\;g/L$, respectively. The viable cell numbers of initial, stationary and death phases were $6.0{\times}10^6,\;1.0{\times}10^8$ and $7.0{\times}10^5\;cfu/mL$ during alcohol fermentation. The sugar fermentability, glucose and fructose contents were greatly decreased less than 0.2 g/L, and the final contents of ethanol and sulfur dioxide were $11.4{\sim}12.3%$ and $40{\sim}62\;mg/L$, respectively. The conversion ratios of malic acid to lactic acid were 23% (G), 67% (M), 28% (C), 33% (GM) and 39% (GC). The chemical characteristics of five red wine were significantly different in pH, total acidity, sulfur dioxide and lactic acid contents (p<0.05).

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.368-374
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• 1999

This study was designed to investigate effects of pulsed electric field (PEF) treatment on physiological changes of microbial cells, using domestically fabricated pilot scale PEF device. The effect of non-thermal PEF treatment on physiological characteristics of microorganisms was determined by salt resistance, the amount of UV absorbents, cell staining, recovery rate of defected cells, and changes in structure of cell membrane. Salt resistance of Escherichia coli, Bacillus subtilis and Rhodotorula minuta was examined after PEF treatment at 40 kV/cm, 84 pulse, $10{\mu}s$ pulse duration. Approximately $1\;log_{10}$ cell number of viable microorganisms was decreased by addition of salt. PEF treatment significantly increased the amount of UV absorbents at 260 and 280 nm because of leakage from damaged cell membrane by PEF treatment. Although three kinds of microorganisms treated by PEF were difficult to be observed due to their cell membrane damage, untreated cells were clearly observed by a microscope. PEF-treated R. minuta was not stained by methylene blue due to cell membrane defect. When E. coli, B. subtilis and R. minuta were cultured after PEF treatment, they showed 5, 4, and 8 hr longer lag phase, respectively, compared to control, but growth rates were not affected.

• Korean Journal of Food Science and Technology
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• v.3 no.3
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• pp.163-167
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• 1971

Tasty constituents of the Chinese quince such as polyphenols, amino acids, sugars and organic acids were surveyed through the course of this study. The results are as follows: 1. The major moiety of the polyphenol constituents were catechin, leucoanthocyan, and associated tannins. 2. Amino acids were mostly composed of aspartic acid, glutamic acid, arginine and ${\beta}-alanine$. 3. Citric and malic acids were the main organic acids. 4. Sugars detected were glucose, fructose, sucrose and xylose. 5. When compared with apple and/or pear: the total amount of amino acids were quite similar, sugars decreased from half to one third, but the total amount of polyphenol constituents increased from 20 up to 50 times and 3 to 5 times in organic acids. These indicates unambiguously that the origin of rough and acidic taste is due to these high level of polyphenols and organic acids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.7
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• pp.848-856
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• 2017

This study aimed to investigate the effect of rice nuruk prepared from rice with different degrees of milling (0, 10, 30, 50, and 70%) on physicochemical qualities of yakju. The results indicated significant differences in the qualities of yakju prepared using rice nuruk from rice with different degrees of milling. Specially, pH, amino acidity, brownness, b value, and color difference were significantly reduced as the degrees of milling increased, whereas contents of alcohol and volatile acid, reducing sugar, and L value were increased. Malic acid, succinic acid, and lactic acid were the main organic acids in yakju, and there were significant differences among the treatments in malic acid, lactic acid. However, there was no tendency according to different degrees of milling. In addition, contents of total free amino acids and nitrogen compounds showed no tendency according to degrees of milling, whereas the content of aspartic acid showed a tendency to decrease significantly. The content of 2-phenyl alcohol in the volatile flavor components showed a tendency to increase significantly with higher degree of milling of rice nuruk, whereas contents of n-propanol and iso-amyl alcohol tended to decrease significantly.

• Korean journal of applied entomology
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• v.41 no.4
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• pp.263-267
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• 2002

A faunistic survey was conducted to find Osmia bees to be used as an effective pollinator in apple orchards. Collections were carried out from more than 50 selected sites in mountainous areas throughout Korea for 3 years (1996-98) with providing bundle of bamboo traps (6-8 mm of inner diameter) as Osmia nesting site. Five species of Osmia ：O. cornifrons (Radoszkowsky), O. pedicornis Cockerell, O. taurus Smith, O. satoi Yasumatsu et Hirashima and O. jacotti Cockerell, were collected at the rates of 39.9-51.7, 28.3-53.7, 5.5-19.1, 0.8-0.9 and 0.0-0.1%, respectively. And O. cornifrons and O. pedicornis were the dominants with over 80% of total Osmia collected through the collections. Out of those bees collected, rates of female were 29-43% for O. cornifrons. 10-12% for O. pedicornis and 22-43% for O. taurus. When the collection sites of the dominant 3 species were grouped in relation to altitudes above the sea level, about 50% or more bees were collected form the higher sites (500m or higher) while 20% or less were from the lower sites (200m or lower). When the bamboo traps were placed at the same sites continuously for 3 years, number of O. cornrfrons and O. taurus collected was slightly increased while that of O. pedicornis was drastically decreased year after year. Nesting by Osmia bees seems to have started at around early April, peaked at early May and ended by Mid June, while nest competing species of Sphecidae and Eumenidae started nesting at around early June, peaked at early July and ended by the Mid August.