• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.5
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• pp.383-391
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• 1992

A comparative study of enzymatic properties between the trypsin from the cat-shark Cephaloscyllium umbratile ( C-T) and the two trypsins from the mackerel Scomber japonicus $(M-T_A\;and\;M-T_B)$ was carried out following after the previous paper(Pyeun et al., 1991). Trypsin from cat-shark(C-T) showed the higher heat stability compared to the others $(M-T_A\;and\;M-T_B)$ and its denaturation constant$(K_D)$ was $10.68\times10^{-4}\;sec^{-1}\;at\;55^{\circ}C$ with BA-p-NA substrate. The activation energies(Ea) of the trypsins measured at a temperature range from $30^{\circ}C\;to\;50^{\circ}C$ were estimated to be 4.07 kcal/mole for C-T, 11.61 kcal/mole for $M-T_A$, and 8.43kcal/mole for $M-T_B$, respectively. The Km values were $24.9\times10^{-5}\;M\;for\;C-T,\;5.37\times10^{-5}\;M\;for\;M-T_A,\;and\;9.65\times10^{-5}\;M\;for\;M-T_B$. On the other hand, the Ki values for TLCK and DFP determined by Dixon plot were $1.50\times10^{-6}\;M\;and\;9.28\times10^{-6}\;M\;for\;C-T\;2.86\times10^{-6}\;M\;and\;2.11\times10^{-4}\;M\;for\;M-T_A\;and\;3.90\times10^{-6}\;M\;and\;1.60\times10^{-4}\;M\;for\;M-T_B$ Similar amino acid profiles were showed between three trypsins each other, with few exceptions of $M-T_B$ containing higher amount of arginine, and the smaller amount of tryptophan in C-T than the others.

• Journal of Life Science
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• v.27 no.6
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• pp.611-616
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• 2017

The antibacterial activities of nine oriental herbal medicine extracts were measured against seven kinds of bacteria known to cause food poisoning and disease. The extracts were prepared with distilled water using an autoclave ($121^{\circ}C$ for 30 min). The extraction yields of nine oriental herbal medicines were in the rage of 0.5%-33.4%. The antibacterial activities were evaluated using the paper-disc method. Extracts of Hwangryeon, Jiyu, and Ohbaeja showed antibacterial activities while the others did not. Extracts of Coptis japonica, Hwangryeon, and Sanguisorba officinalis, Jiyu showed antibacterial activities only against Clostridium perfringens and Listeria monocytogenes. Extracts of Rhus javanica, Ohbaeja showed the strongest antibacterial activities against all the bacteria tested. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of R. javanica extracts were in the range of 2.4~20 mg/ml for the bacteria tested. In conclusion, the extract of R. javanica showed superior antibacterial activities against the seven bacterial strains tested. The MIC and MBC values for each bacterium were represented as strain names (MIC, MBC), which were Bacillus cereus (11.2, 20), Clostridium perfringens (2.4, 4.7), Escherichia coli (9.1, 9.1), Listeria monocytogenes (11.1, 20), Salmonella typhi (4.7, 9.1), Staphylococcus aureus (2.4, 4.7), and Vibrio parahaemolyticus (2.4, 5.3). Further purification and study of this antibacterial material would be helpful for developing antibiotics or promoting synergistic effects with known antibiotics, producing antibacterial material for lengthening the shelf-life of food, and so on.

• Korean Journal of Food Science and Technology
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• v.38 no.3
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• pp.419-426
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• 2006

A thermophilic microorganism, strain JE 375, which produces a thermostable protease, was isolated from soil and compost in Korea. This gram-positive, rod-shaped, catalase positive, motility positive, and hemolysis ${\beta}$ containing organism was implicated in glucose fermentation, mannitol fermentation, xylose oxidation, aerobic activity and spore formation. The color of the colony was yellowish white. The temperature range for growth at pH 6.5 was between 55 and $70^{\circ}C$, with an optimum growth temperature of $65^{\circ}C$. This result confirmed the strain JE 375 as a thermophilic microorganism. The enzyme was produced aerobically at $65^{\circ}C$ during 20 hr in a medium (pH 6.5) containing 1% trypton. 1% maltose, 0.5% yeast extract and 1% NaCl. The 16S rDNA of strain JE 375 had 97.6% sequence similarity with the 16S rDNA of Bacillus caldoxyloyticus. On the basis of biochemical and physiological properties and phylogenetic analysis, we named the isolated strain as Bacillus sp. JE 375. The thermostable protease from Bacillus sp. JE 375 had been partially purified and characterized. The molecular weight of the enzyme was deduced from SDS-PAGE and gel chromatography as 55 kDa and its optimal temperature was $60^{\circ}C$. The enzyme showed its highest activity at pH 7.5 and was stable from pH 7.0 to 8.0.

• Clean Technology
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• v.13 no.4
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• pp.266-273
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• 2007

The adsorption properties of the activated carbon-based adsorbents were studied to remove COS emitted from $SO_2$ catalytic reduction process on the integrated gasification combined cycle (IGCC) system in this work. Transition metal supported catalysts and mixed metal oxide catalysts were used for the $SO_2$ catalytic reduction. The mechanism of COS produced from the $SO_2$ reduction and the COS concentration s according to the reaction temperature were investigated. In this study, an activated carbon and a modified activated carbon doped with KOH were used to remove the very low concentration of COS effectively. The adsorption rate and the breakthrough time of COS were measured by a thermo gravity analyzer (TGA, Cahn Balance) and a fixed bed flow reactor equipped with GC-pulsed flammable photometric detector (PFPD), respectively. It was confirmed that the COS breakthrough time of the activated carbon doped with KOH was longer than that of an activated carbon. In conclusion, the modified-activated carbon having a high surface area showed a high adsorption rate of COS produced from the $SO_2$ reduction.

• Journal of Life Science
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• v.26 no.12
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• pp.1477-1486
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• 2016

Lactulose (4-O-${\beta}$-D-galactopyranosyl-D-fructose) is a non-digestible synthetic ketose disaccharide which can used in food and pharmaceutical fields due to its useful functions for encephalopathy, chronic constipation, hyperammonemia, etc. Therefore, the lactulose is regarded as one of the most important disaccharides and have been concentrated much interesting as an attractive functional material in the current industry. From this reason, the research related on the production of lactulose has been carried out various academic and industrial research groups. To produce lactulose, two main methods, chemical production and enzymatic production have been used. Commercially lactulose produced by alkaline isomerization of lactose as chemical production method but it has many disadvantages such as rapid lactulose degradation, purification, and waste management. From these reasons, lactulose produced by enzymatic method which solves these problems has been suggested as a proper method for lactulose production. Two different enzymatic methods have been reported as methods for lactulose production. Lactulose can be obtained through hydrolysis and transfer reaction catalyzed by a ${\beta}$-galactosidase which requires fructose as co-substrate and exhibits a low conversion. Alternatively, lactulose can be produced by direct isomerization of lactose to lactulose catalyzed by cellobiose 2-epimerase which requires lactose as a single substrate and achieves a high lactulose yield. This review summarizes the current state of lactulose production by chemical and biological methods.

• Journal of Food Hygiene and Safety
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• v.24 no.2
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• pp.169-173
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• 2009

A survey of total aflatoxin levels was conducted on 145 samples(carthamiflos, thujae semen, giycyrrhizae radix et rhizoma) collected in Yakyeang markets in Seoul. Aflatoxin levels were quantified by the immunoaffinity column clean-up method followed by performance liguid chromatography(HPLC)-fluorescence detector(FLD). Aflatoxins were found in 10(6.9%)samples including 5 Arecae semen, 4 Thujae semen, 1 Zizyphi semen with a range of $0.45{\sim}79.15\;{\mu}g/kg$. Generally These results show that the contamination level of aflatoxins in Herb Medicines consumed in Korea is high compared with the standard in Korea Herb Medicine Code($10\;{\mu}g/kg$ as aflatoxin B1). It is considered that aflatoxin concentration was increased in herb medicines during a storage and drying in herb medicines examined

• Analytical Science and Technology
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• v.23 no.6
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• pp.544-550
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• 2010

Mistaking pink colored thermal oil for grape wine, a victim drank the oil to death which was analyzed to contain 39% of ethylene glycol. Thermal oil could be used for heat transfer to prevent the malfunction due to the high pressure in the boiler operated at high temperature when using water. Main component of thermal oil is known to be mineral oil or ethylene glycol. From the blood and other tissue of the victim from autopsy, ethylene glycol and its metabolite were simultaneously analyzed by GC/MS after extraction under acidic condition with acetonitrile followed by derivatization with BSTFA. About 0.2 g of the specimens were pretreated with 50 uL of 0.5 M HCl solution to keep acidic condition, then dehydrated with anhydrous sodium sulfate followed by concentration under nitrogen stream. Ethylene glycol and glycolic acid concentration in blood was measured to be $2,755\;{\mu}g/mL$ and $174\;{\mu}g/mL$ respectively. In other specimen, the concentration of ethylene glycol and glycolic acid was $860\;{\mu}g/g\sim1,290\;{\mu}g/g$ and $93\;{\mu}g/g\sim134\;{\mu}g/g$. Especially, crystal appeared in kidney which was supposed xalate from the metabolite of ethylene glycol.

• Clean Technology
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• v.26 no.2
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• pp.91-95
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• 2020

A new eco-friendly synthetic method for N-hydroxysuccinimide (NHS), widely used in the pharmaceutical and fine chemical industries, is developed. Conventional synthesis method yields NHS of about 70% after its reaction with NH₂OH to succinic acid. In this method, NHS can be obtained using low-cost succinic acid, but a great deal of solvents are required as an extraction method to purify NHS, while the work-up process is complicated, resulting in low yield. In addition, there is a safety risk due to the high reaction temperature for commercial production, and it is not economical due to the high cost of production from the generation of much waste because of an acid catalyst and the use of various solvents. In order to make up for this shortcoming, this study used succinic anhydride as a raw material under low temperature reaction and developed a new eco-friendly industrial synthesis method using isobutyl alcohol for a single solvent and non-catalytic reaction. The economic evaluation confirms that there is a cost reduction effect of about 20%. In the future, based on this result, studies may establish a commercial production technology through scale-up research and proceed with foreign technology transfer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.9 no.1
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• pp.15-22
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• 1980

In this study, two species of algae, Ecklonia stolonifera, Sargassum thunbergii and one species of marine plant, Zostera marina(rhizoid and stem) were collected and extamined to determine the extractability of water soluble protein and the influences of various factors including extraction time, temperature, ratio of sample vs solvent and pH upon the extractability were tested. The effects of precipitation treatments for isolation of algal protein from the extracts(TCA treatment, methanol treatment and pH control) were also tested. Amino nitrogen and total nitrogen of purified samples made by obtained optimum conditions were estimated. The effect of the ratio of sample vs solvent on extractability differed from species to species which was enhances at 1:100(w/v) in Sargassum thunbergii and Zostera marina while 1:150(w/v) for Ecklonia stolonifera. The effect of extraction time and temperature was revealed differently in all species which might be considered to be caused by differences in the constitution of algal tissues. But in case of TCA insoluble nitrogen, it was showed the maximum extractability at $40-50^{\circ}C$ for 1 hour extraction. The optimum pH for the ext action of total nitrogen was 9-12 while the optimum pH was 6-7 for TCA insoluble nitrogen. And the pH control appeared to be most effective in the influence of precipitation treatment for isolation of algal protein.

• Korean Journal of Food Science and Technology
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• v.20 no.2
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• pp.218-224
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• 1988

For the optimization of thermal processing conditions in soymilk process, 4 strains of thermoresistant flat-sour bacteria were isolated from soymilk. The isolates were aerobic spore-forming rods, and grew at $-65^{\circ}C$. Based on the morphological and physiological properties, all of the isolated strains were identified as Bacillus stearothermophilus. The heat resistance of spores of 3 isolates and Bacillus stearothermophillus ATCC 12980 as a reference was determined in soymilk(pH 7.0) and pH 7.0 buffer solution. For each of the spores studied, linear regression equations with standard error were presented for the thermal destruction at 110, 115, 121, and $125^{\circ}C$. It was not obvious that the components of soy milk increased the heat resistance of spores. Between the strains studied, variability was noted in the D values at the different temperature, and no one strain was consistently the most heat resistant at all the given temperatures. The average D value for the 4 strains was 77.27, 20.20, 2.76 and 1.39 min at 110, 115, 121 and $125^{\circ}C$, respectively, and the average z value was $8.36^{\circ}C$.