• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.210-217
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• 2015

Ipfencarbazone is a herbicide of the tetrazolinone class, and is believed to be an inhibitor of very long chain fatty acids (VLCFAs), which control cell division in weeds. The objective of this study was to develop and validate an official analytical method for ipfencarbazone determination in agricultural products. The ipfencarbazone residues in agricultural products were extracted with acetone, partitioned with n-hexane, and then purified through silica SPE cartridge. Finally, the analyte was quantified by gas chromatograph-electron capture detector (GC-ECD) and confirmed with gas chromatograph/mass spectrometer(GC/MS). The linear range of ipfencarbazone was 0.01 to 1.0 mg/L with the coefficient of determination ($r^2$) of 0.9999. The limit of detection (LOD) and quantification (LOQ) was 0.003 and 0.01 mg/kg, respectively. In addition, average recoveries of ipfencarbazone ranged from 80.6% to 112.3% at the different concentration levels LOQ, 10LOQ and 50LOQ, while the relative standard deviation was 2.2-8.6%. All values were consistent with the criteria ranges requested in the CODEX guidelines. Furthermore, and inter-laboratory study was conducted to validate the method. This proposed method for determination of ipfencarbazone residues in agricultural products can be used as an official analytical method.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.296-305
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• 2018

Spiroxamine, one of fungicides, is used to control powdery mildew in various crops and black yellow sigatoka in bananas. The major strength of spiroxamine is to control powdery mildew in various crops and bananas yellow sigatoka in bananas. The compound has shown a high level of activity, good persistence and crop tolerance. Besides powdery mildew, good control of rust, net blotch and Rhynchosporium diseases been indicated in cereals, together with a complementary activity against Septoria diseases. In 2017, the maximum residue limit (MRL) of spiroxamine established in Korea. According to Ministry of ood and rug afety) regulations, spiroxamine residues defined only parent compound. Thus, a analytical method is needed to estimate the residue level of the parent compound. The objective of this study was to develop and validate analytical method for spiroxamine in representative agricultural commodities. Samples were extracted with acetonitrile and partitioned with dichloromethane to remove the interfering substances. The analyte were quantified and confirmed liquid chromatograph-tandem mass spectrometer (LC-MS/MS) in positive-ion mode using multiple reaction monitoring (MRM). Matrix matched calibration curves were linear over the calibration ranges ($0.0005{\sim}0.1{\mu}g/mL$) for the analyte in blank extract with coefficient of determination ($r^2$) > 0.99. For validation purposes, recovery studies will be carried out at three different concentration levels (LOQ, 10LOQ, and 50LOQ) performing five replicates at each level. The recoveries 70.6~104.6% with relative standard deviations (RSDs) less than 10%. All values were consistent with the criteria ranges in the Codex guidelines (CAC/GL40, 2003) and MFDS guidelines. proposed analytical method be used as an official analytical method in the Republic of Korea.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1688-1694
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• 2014

Jeju Hallabong Tangor (Citrus kiyomi${\times}$ponkan) is a Citrus species with a variety of physiological properties such as anti-oxidant, anti-inflammation, anti-cancer, and anti-obesity. We investigated the anti-obesity effects of Hallabong Tangor peel extracts before (HLB) and after (HLB-C) bioconversion with cytolase based on modulation of adipocyte differentiation and lipid metabolism in 3T3-L1 adipocytes. Treatment with cytolase decreased flavanone rutinoside forms (narirutin and hesperidin) and increased flavanone aglycone forms (naringenin and hesperetin). During adipocyte differentiation, 3T3-L1 cells were treated with 0.5 mg/mL of Sinetrol (a positive control), HLB or HLB-C. Adipocyte differentiation was inhibited in both citrus groups, but not in control and Sinetriol groups. HLB and HLB-C tended to reduce insulin-induced mRNA levels of CCAAT/enhancer-binding protein ${\alpha}$ ($C/EBP{\alpha}$) and sterol regulatory element-binding protein 1c (SREBP1c). Compared to the control and Sinetrol groups, HLB and HLB-C markedly suppressed insulin-induced protein expression of $C/EBP{\alpha}$ and peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$). The HLB and Sinetrol groups, but not HLB-C group, significantly increased adipolytic activity with higher release of free glycerol compared to the control group in differentiated 3T3-L1 adipocytes. These results suggest that bio-conversion of Hallabong Tangor peel extracts with cytolase increases aglycone flavonoids. Irrespective of bioconversion, both Hallabong Tangor peel extracts exert anti-obesity effects that may contribute to prevention of obesity through inhibition of adipocyte differentiation or induction of adipolytic activity.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.388-394
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• 2014

BACKGROUND: Aclonifen is used as a systemic and selective herbicide to control a wide spectrum broad-leaf weeds by inhibition carotenoid biosynthesis, and then its MRLs(Maximum Residue Limits) will be determined in onion and garlic. In this study, a new official method was developed for aclonifen determination in agricultural products to routinely inspect the violation of MRL as well as to evaluate the terminal residue level. METHODS AND RESULTS: Aclonifen was extracted from crop samples with acetone and the extract was partitioned with dichloromethane and then purified by silica solid phase extraction(SPE) cartridge. The purified samples were detected GC using an ECD detector. Limits of detection(LOD) was 0.001 mg/kg and quantification(LOQ) was 0.005 mg/kg, respectively. For validation purposes, recovery studies were carried out at three different concentration levels (LOQ, $10{\times}LOQ$, $50{\times}LOQ$, n=5). The recoveries were ranged from 74.3 to 95.0% with relative standard deviations(RSDs) of less than 8%. All values were consistent with the criteria ranges requested in the Codex guidelines(CAC/GL 40). CONCLUSION: The proposed analytical method was accurate, effective and sensitive for aclonifen determination and it will be used to as an official method in Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.34 no.4
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• pp.296-306
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• 2014

This study was conducted to survey and analyze the quantity of various organic wastes and to vitalize the utilization of agri-food by-products as raw materials for Total mixed ration (TMR), to improve feed cost savings and the quality of animal products. On-the-spot obstacles for animal farmers, along with legal and institutional alternatives are presented. The results are as follows. First, organic wastes in Korea are managed by the Allbaro system created in the Wastes Control Act, which processes 10,488 tons of cooking oil waste, 832,493 tons of animal and plant residues, 5,740 tons of animal carcasses, 1,171,892 tons of animal residues, and 2,172,415 tons of plant residues including 12,905 tons of rice hull and bran, for a total of 4,205,931 tons. Raw materials for TMR, namely rice hulls and bran as well as plant residues, accounted for 51.7% of the total national organic waste. The top 10 municipalities process 76~100% of all organic wastes and a supply management system is needed for the waste. Second, the 10 major agri-food by-products used as raw materials for TMR are bean curd by-product, rice bran, oil-cake, brewers dried grain, Distiller's Dried Grains with Solubles (DDGS), barley bran, soy sauce by-product, citrus fruit by-product, mushroom by-product and other food by-product (bread, noodles, snacks, etc.). Third, the biggest difficulties in using agri-food by-products are legal obstacles. Because agri-food by-products are regulated as industrial wastes by the Waste Control Act, animal farmers that wish to use them have legal reporting obligations including the installation of recycling facilities. To enable the use of agri-food by-products as raw materials for TMR, waste management system improvements such as 'the end of waste status' and the establishment of more than 10 public distribution centers nationwide are deemed essential.

• Horticultural Science & Technology
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• v.33 no.2
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• pp.283-291
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• 2015

The aim of this study was to evaluate the changes of fruit quality, flavonoid contents and antioxidant activity of Yuzu (Citrus junos Sieb. ex Tanaka) from Go-heung and Jeju according to harvest time. Samples were harvested from August to December on the $1^{st}$ of every month. August and September samples were green colored, whereas November and December samples were yellow. The fruit shape index decreased, changing from globular to elliptical, whereas the $^{\circ}birx$ increased with ripening stage. The yuzu from Jeju was larger than that from Go-heung in each month of cultivation. August samples exhibited the highest amounts of phenolic compounds. In addition, samples from Jeju had higher total phenolic content than those from Go-heung. The content of phenolic compounds decreased with ripening until October and then increased subsequently. Antioxidant activity of the yuzu was evaluated by FRAP and DPPH methods. The antioxidant activity showed a similar trend as total phenolic content. Immature yuzu fruit was found to exhibit the highest amount of flavonoids such as naringin and hesperidin. November and December samples showed almost the same contents of flavonoids. The flavonoid content of yuzu fruit harvested from Jeju was higher than that from Go-heung. Overall, the samples harvested at the early stage, in the month of August, exhibited the highest flavonoid content, phenolic content and antioxidant activity. As the health benefits of these compounds has been demonstrated in various studies, the immature yuzu appears to be preferable for use as a raw material for formulation of pharmaceutical products as well as for functional food production after a proper in-vivo and in-vitro medical tests.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.230-234
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• 2011

According to the Codex committee, the maximum allowable level for lead in fruits is 0.1 mg/kg. This survey was conducted as a surveillance program following the establishment of safety guideline for fruits in Korea. Concentrations of lead (Pb), cadmium (Cd), arsenic (As) and mercury (Hg) were measured in 927 samples using a ICP-MS and a mercury analyzer. The recoveries of microwave digestion method were 86.0-110.4% for Pb, 81.0-104.0% for Cd and 82.0-104.7% for As by standard addition method. The recovery of direct mercury analyzer was 106.5% for Hg. The average levels of Pb in ${\mu}g/kg$ were $10.0{\pm}12.8$ for apple, $8.8{\pm}10.9$ for pear, $4.1{\pm}4.4$ for persimmons, $14.9{\pm}12.3$ for mandarin, $7.1{\pm}6.5$ for orange, $3.1{\pm}3.3$ for banana, $8.8{\pm}8.9$ for kiwi, and $9.3{\pm}9.7$ for mango. The average levels of Cd in ${\mu}g/kg$ were $0.4{\pm}0.3$ for apple, $2.0{\pm}1.6$ for pear, $0.3{\pm}0.3$ for persimmon, $0.1{\pm}0.1$ for mandarin, $0.1{\pm}0.1$ for orange, $1.3{\pm}1.8$ for banana, $0.5{\pm}0.5$ for kiwi, and $0.7{\pm}0.6$ for mango. The average levels of As in ${\mu}g/kg$ were $2.0{\pm}2.1$ for apple, $1.2{\pm}1.3$ for pear, $1.5{\pm}1.2$ for persimmon, $0.8{\pm}0.3$ for mandarin, $1.5{\pm}0.5$ for orange, $1.8{\pm}1.2$ for banana, $1.6{\pm}1.5$ for kiwi, and $1.2{\pm}1.5$ for mango. The average levels of Hg in ${\mu}g/kg$ were $0.5{\pm}0.4$ for apple, $0.3{\pm}0.2$ for pear, $0.2{\pm}0.1$ for persimmon, $0.2{\pm}0.1$ for mandarin, $0.2{\pm}0.1$ for orange, $0.2{\pm}0.0$ for banana, $0.2{\pm}0.2$ for kiwi, and $0.6{\pm}0.2$ for mango. Based on the Korean public nutrition report 2005, these levels (or amounts) are calculated only at 0.17% for Pb, 0.013% for Cd and 0.006% for Hg of those presented in provisional tolerable weekly Intake (PTWI) which has been established by FAO/WHO. Therefore, the levels presented here are presumed to be adequately safe.

• The Korean Journal of Pesticide Science
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• v.20 no.2
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• pp.93-103
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• 2016

A simultaneous analytical method was developed for the determination of isoxaflutole and metabolite (diketonitrile) in agricultural commodities. Samples were extracted with 0.1% acetic acid in water/acetonitrile (2/8, v/v) and partitioned with dichloromethane to remove the interference obtained from sample extracts, adjusting pH to 2 by 1 N hydrochloric acid. The analytes were quantified and confirmed via liquid chromatograph-tandem mass spectrometer (LC-MS/MS) in positive-ion mode using multiple reaction monitoring (MRM). Matrix matched calibration curves were linear over the calibration ranges ($0.02-2.0{\mu}g/mL$) for all the analytes into blank extract with $r^2$ > 0.997. For validation purposes, recovery studies were carried out at three different concentration levels (LOQ, 10LOQ, and 50LOQ) performing five replicates at each level. The recoveries were ranged between 72.9 to 107.3%, with relative standard deviations (RSDs) less than 10% for all analytes. All values were consistent with the criteria ranges requested in the Codex guideline (CAC/GL40, 2003). Furthermore, inter-laboratory study was conducted to validate the method. The proposed analytical method was accurate, effective, and sensitive for isoxaflutole and diketonitrile determination in agricultural commodities.

• Food Science and Preservation
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• v.23 no.3
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• pp.438-444
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• 2016

This study was performed to determine the optimal freezing point for the reliable cold storage of Korean agricultural products, and to provide basic data for determining the storage temperature based on the quality characteristics. Additional supercooling temperature analysis was conducted to explore the possibility of supercooling storage. To determine the effects of quality characteristics on the freezing point, the hardness, acidity, moisture and sugar content were analyzed. The crops were frozen using customized cooling unit and their freezing and supercooling points were determined based on their heat release points. The freezing temperatures of garlic, leek, cucumber, hot pepper, grape, oriental melon, netted melon, peach, cherry tomato, plum, daikon, sweet persimmon, apple, sweet potato, mandarin, pear, and strawberry were -1.6, -0.5, -0.5, -0.7, -1.6, -1.6, -1.3, -0.8, -0.3, -1.1, -0.3, -1.7, -1.5, -1.5, -0.8, -1.5, and -$0.9^{\circ}C$, respectively; otherwise, supercooling points were -7.8, -3.7, -3.3, -4.9, -5.7, -4.6, -2.8, -3.3, -5.9, -4.2, -0.8, -4.7, -3.2, -3.7, -4.7, -4.2, and -$3.4^{\circ}C$, respectively. These results suggest that the ideal freezing temperature of crops could be estimated through freezing point depression because of their sugar content, and this technique should be used to maintain an optimum storage temperature. However, cold storage is complicated and further study is required because of the effects of long-term cold storage on the crops.

• Korean Journal of Food Science and Technology
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• v.45 no.2
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• pp.148-155
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• 2013

Sulfoxaflor is a new active ingredient within the sulfoximine insecticide class that acts via a unique interaction with the nicotinic receptor. The MRLs (maximun residue limit) of sulfoxaflor in apple and pear are set at 0.4 mg/kg and that in pepper is set at 0.5 mg/kg. The purpose of this study was to develop an analytical method for the determination of sulfoxaflor residues in agricultural commodities using HPLC-UVD and LC-MS. The analysis of sulfoxaflor was performed by reverse phase-HPLC using an UV detector. Acetone and methanol were used for the extraction and aminopropyl ($NH_2$) cartridge was used for the clean-up in the samples. Recovery experiments were conducted on 7 representative agricultural products to validate the analytical method. The recoveries of the proposed method ranged from 82.8% to 108.2% and relative standard deviations were less than 10%. Finally, LC-MS with selected ion monitoring was also applied to confirm the suspected residues of sulfoxaflor in agricultural commodities.