• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.365-371
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• 1999

Microwave-assisted extraction (MAE) is known as a more environmental-friendly process with economic advantages in terms of less time, less solvent, less energy and less waste than the current reflux method that is time-consuming. MAE was applied to extract three pesticides (quintozene, tolclofos-methyl and procymidone) from ginseng in a pesticide residue analysis and eliminate pesticide contaminants from ginseng prior to production of the ginseng extracts. The optimal conditions for pesticide extraction from ginseng were 50% in power (150 watts), 2 minutes, 20 mL hexane and 2.0 g sample. The results of optimal conditions were compared with those of Soxhlet method (7 hours, 150 mL hexane). The recoveries between two methods were almost same while time and amount of solvent used in MAE were significantly decreased in comparing with those in the Soxhlet methods. When the 45% ethyl alcohol as a extraction solvent was applied to eliminate pesticides from ginseng prior to the production of the ginseng extracts, it was found that 100% quintozene, 69％ tolclofos-methyl and 83% procymidone were eliminated from ginseng. The data showed that MAE may be used to eliminate pesticide contaminants in ginseng prior to making the ginseng extracts.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.511-511
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• 2009

Lignocellulosic biomass is the most abundant organic material on earth and also promising raw material for bioenergy production. Agricultural residues in the process of bio-oil extraction, is an abundant and low-cost lignocellulosic material. The technology for conversion of lignocellulosic biomass resources to fuels and chemicals, such as ethanol, has been under development for decades. One of the well-studied technologies that are currently being commercialized is to use a dilute acid-catalyzed pretreatment followed by enzymatic hydrolysis and fermentation to produce ethanol. In this work, the dilute-acid hydrolysis of agricultural residues was optimized through the utilization of statistical experimental design. Evaluation criteria for optimization of the pretreatment conditions were based on high xylose recovery and low inhibitor contents in the hydrolyzates. The purpose of this study was to gain a more accurate understanding of the quantities of acid required for effective hydrolysis and the reactivity trade-offs with reaction time and temperature that will enable overall process optimization.

• Korean Journal of Environmental Agriculture
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• v.23 no.4
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• pp.251-257
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• 2004

Analytical methods were developed to determine cyclosulfamuron residues in soil, water, rice grain and straw using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. In these methods, cyclosulfamuron was extracted with aqueous $Na_2HPO_4$/acetone and acetone/methanol mixture from soil and rice samples respectively. Liquid-liquid partition coupled with ion-associated technique, Florisil column chromatography, and solid-phase extraction (SPE) were used to separate cyclosulfamuron from interfering co-extractives prior to HPLC analysis. For water sample, the residue was enriched in $C_{18}$-SPE cartridge, cleaned up in situ, and directly subjected to HPLC. Reverse-phase HPLC under ion-suppression was successfully applied to determine cyclo-sulfamuron in sample extracts with the detection at its ${\lambda}_{max}$ (254 nm). Recoveries from fortified samples averaged $87.8{\pm}7.1%$ (n=12), $97.3{\pm}7.2%$ (n=12), $90.8{\pm}6.6%$ (n=6), and $78.5{\pm}6.7%$ (n=6) for soil, water, rice grain and straw, respectively. Detection limits of the methods were 0.004 mg/kg, 0.001 mg/L, 0.01 mg/kg and 0.02 mg/kg for soil, water, rice grain and straw samples, respectively.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.487-496
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• 2021

Microalgae is one of the promising biodiesel feedstock with high growth rates compared to those of terrestrial oil crops. Despite its numerous advantages, biodiesel production from microalgae needs to reduce energy demand and material costs further to go to commercialization. During solvent extraction of microalgal lipids, lipid-extracted algae (LEA) cell residue is generated as an organic solid waste, about 80-85% of original algal biomass, and requires an appropriate recycling or economic disposal. The resulting LEA still contains significant amount of carbohydrates, proteins, N, P, and other micronutrients. This review will focus on recent advancement in the utilization of LEA as: (i) utilization as nutrients or carbon sources for microalgae and other organisms, (ii) anaerobic digestion to produce biogas or co-fermentation to produce CH₄ and H₂, and (iii) conversion to other forms of biofuel through thermochemical degradation processes. Possible mutual benefits in the integration of microalgae cultivation-biodiesel production-resulting LEA with anaerobic digestion and thermochemical conversion are also discussed.

• The Korean Journal of Food And Nutrition
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• v.17 no.2
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• pp.147-155
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• 2004

Freeze dried antler, heat dried antler, antler were extracted through processing step by water, protease and hydrochloric acid(HCl). Extraction rate of freeze dried antler at 50$^{\circ}C$ by water was 9.01％(8.82, absorbance at 280 nm), that of heat dried antler was 9.01％(4.45, absorbance at 280 nm), and that of antler was 1.10％(0.31, absorbance at 280 nm), respectively. Extraction rate of freeze dried antler by bacterial protease was 16.89％(4.50, absorbance at 280 nm), and that of heat dried antler was 17.29％(5.62, absorbance at 280 nm), and that of antler was 18.22％(0.64, absorbance at 280 nm), respectively. Extraction rate of freeze dried antler by 0.8N HCl was 72.25％(4.60, absorbance at 280 nm), that of heat dried antler was 71.14％(4.70 absorbance at 280 nm), and that of antler was 79.82％ (2.80, absorbance at 280 nm), respectively. Extraction rate of freeze dried antler through three processing steps was 98.15％, that of heat dried antler was 97.35％, that of antler was 99.14％, respectively. The result of analysis by HPLC shows that high molecular pe which appears in young antler and antler extraction was changed into a small molecular peak of about 1,000 by the reaction of protease, and protein of about MW 70,000 was extracted from their remaining residue by 0.8N HCl. The above result shows that water extraction and protease extraction in the freeze dried young antler, protease extraction and HCl extraction in dried young antler, and HCl extraction in antler are most effective.

• Korean Journal of Environmental Agriculture
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• v.37 no.2
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• pp.117-124
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• 2018

BACKGROUND: Oxycarboxin(5,6-dihydro-2-methyl-N-phenyl-1,4-oxathiin-3-carboxamide-4,4-dioxide) as oxanthiin is a systemic fungicide commonly used for control of various pathogens in agronomic and horticultural crops. In an effort to develop an analytical method to trace the fungicide, a method using HPLC equipped with UVD/MS was studied. METHODS AND RESULTS: Oxycarboxin was extracted with acetone from hulled rice, soybean, Kimchi cabbage, green pepper, and apple samples. The extract was diluted with saline water, followed by liquid-liquid extraction with methylene chloride. Florisil column chromatography was employed for the purification of the extracts. Oxycarboxin was determined on a Zorbax SB-AQ $C_{18}$ column by HPLC with UVD. Accuracy of the proposed method was validated by the recovery tests from crop samples fortified with oxycarboxin at 3 levels per crop. CONCLUSION: Mean recoveries ranged from 78.3% to 96.1% in five representative agricultural commodities. The coefficients of variation were less than 10%, and limit of quantitation of oxycarboxin was 0.04 mg/kg. A confirmatory technique using LC/MS with selected-ion monitoring was also provided to clearly identify the suspected residue. The method was reproducible and sensitive to determine the residue of oxycarboxin in agricultural commodities.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.128-135
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• 2013

BACKGROUND: This study was performed to develop a single residue analytical method for new herbicide metazosulfuron in crops. METHODS AND RESULTS: Brown rice, apple, mandarin, Kimchi cabbage and soybean were selected as representative crops, and clean-up system, partition solvent and extraction solvent were optimized. Instrumental limit of quantitation (ILOQ), linearity of calibration curve and method limit of quantitation (MLOQ) were determined based on the chromatography and whole procedures. For recovery tests, brown rice, apple, mandarin, Kimchi cabbage and soybean samples were macerated and fortified with metazosulfuron standard solution at three levels (MLOQ, 10 MLOQ and 100 MLOQ). And then those were extracted with acetonitrile, concentrated, and partitioned with ethyl acetate. Then the extracts were concentrated again and cleaned-up through $NH_2$ (aminopropyl) SPE cartridge with acetone : dichloromethane (1% acetic acid) (20 : 80, v/v) before concentration and analysis with HPLC. CONCLUSION(S): ILOQ of metazosulfuron was 2 ng (S/N${\geq}$10) and good linearity was achieved between 0.05 and 12.5 mg/Kg of metazosulfuron standard solutions, with coefficients of determination of 0.9999. MLOQ was 0.02 mg/Kg. Good recoveries from 74.1 to 116.9% with coefficients of variation (C.V.) of less than 10% were obtained, regardless of sample type, which satisfies the criteria of Korea Food and Drug Administration (KFDA). Those results were reconfirmed with LC-MS (SIM). The method established in this study is simple, economic and efficient to be applied to most of crops as an official and general method for residue analysis of metazosulfuron.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.2
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• pp.158-161
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• 2005

We have isolated fractions from Cordyceps militaris and Paecilomyces japonica and investigated their effects on the activity of rat liver cytosolic glucokinase, a key metabolic enzyme involved in carbohydrate metabolism. The dried powder of the C. militaris and P. japonica were successively extracted with ethanol and with 70% ethanol. The residue was exhaustively extracted with hot water. The extract was dialyzed against water, and to the non-dialyzable solution was added 2 volumes of ethanol. The precipitate was collected by centrifugation dispered in water, and lyophilized to afford fraction A. The residue after hot-water extraction was suspended in 5% sodium carbonate. The final residue was suspended in 5% NaOH. The alkaline suspension was purified in a similar manner as described above to afford fraction B. Hepatic glucokinase activities of the fraction A extracted from C. militaris and P. japonica were 371.4 and 379%, respectively. The fraction B was 314.2 and 147.4%. The activity of fraction B of C. militaris extracts was higher than that of P. japonica. Liver cytosolic glucokinase activity of rats fed normal diet supplemented with 0.1% C. militaris was 1316%. In conclusion, the present study has demonstrated that C. militaris extracts were able to prevent sudden postprandial peaks in blood glucose as a result of a marked increase in the liver cytosolic glucokinase activities.

• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.281-286
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• 2019

A black tea (Camellia sinensis L.) residue extract (BTRE) was prepared by 30% ethanol extraction to evaluate its in vitro antioxidant activity. The yield and polyphenol content of BTRE were $22.4{\pm}1.18%$ and $23.2{\pm}1.02{\mu}g$ gallic acid equivalents/mg-extract, respectively. Antioxidant activity of BTRE proportionally increased as BTRE concentration increased. $IC_{50}$ values of BTRE for cation radical, free radical and nitrite scavenging were 141.8, 108.1, and $397.2{\mu}g/mL$, respectively. Also $IC_{50}$ value of BTRE for ferric reducing anti-oxidant power was $97.8{\mu}g/mL$. BTRE effectively inhibited linoleic acid peroxidation. These results imply that BTRE possessed potent antioxidant activity, thus being utilized as a physiologically active material.

• Korean Journal of Environmental Agriculture
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• v.41 no.2
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• pp.95-100
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• 2022

BACKGROUND: This study was aimed to determine characteristics of residues of the soil-treated boscalid and pyraclostrobin within Hylomecon vernalis and to evaluate the risks from intake of the residual pesticides in the crop. METHODS AND RESULTS: The pesticides were treated to soils at two different concentrations, and the plant samples were collected 57 days after seeding. The samples were extracted using the QuEChERS extraction kit (MgSO₄ 4 g, NaCl 1 g). The quantitative methods for boscalid and pyraclostrobin were validated using linearity, recovery, and CV (coefficient of variation). Risk assessment of the pesticides was performed using Korea national nutrition statistics 2019. CONCLUSION(S): The residual levels of boscalid were 0.02-0.05 mg/kg (for the treatment at 6 Kg/10a) and 0.05-0.08 mg/kg (for the treatment at 12 Kg/10a), respectively. The residual concentrations of pyraclostrobin were below the LOQ. The amounts of pesticides were less than Maximum Residue Limits specified by the Korean Ministry of Food and Drug Safety. The maximum hazard indices of boscalid in chwinamul and amaranth for consumers were 0.0075% and 0.1525%, respectively, and it indicates that the risk of the pesticides from the crop is considered to be low.