• Journal of Korean Society of Environmental Engineers
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• v.32 no.2
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• pp.121-130
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• 2010

Metals and sulfate can be considerably dissolved at low pH condition in the acid mine drainage(AMD) and it would make an environmental problems. There are only few of acid mine drainage treatment systems in Korea which are operating, but these still have an effect on the surrounding stream. In this study, quantification of indicator microorganisms was conducted to judge the environmental impact of AMD on microflora by quantitative real-time PCR in the drainage samples of four mines and the water samples of each surrounding stream. Two species of iron reducing bacteria(Rhodoferax ferrireducens T118 and Acidiphilium cryptum JF-5) were selected for indicator bacteria based on 16S rRNA cloning analysis, and sulfate reducing bacteria(Desulfosporosinus orientus), iron and sulfur oxidizing bacteria(Acidothiobacillus ferrooxidans) and iron oxidizing bacteria(Leptosprillum ferrooxidans) were included into indicator since these were found in the previous studies on the mining area. Thereafter, the comparative analysis of four mines were established by the microbiological variation index and it was determined that the biological environment effect of AMD is highest in Samtan mine which doesn t contain treatment system by the value.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.6
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• pp.731-736
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• 2016

No freshness indicator for fish has yet been established. Thus, we investigated changes over time in mackerel quality in an effort to development useful indicators. Fresh whole mackerel Scomber japonicus were stored at $4^{\circ}C$ immediately after capture and quality changes were evaluated every 3 days for a total of 15 days. Whole fish were divided into ventral parts (VPs) and dorsal parts (DPs); we measured the trimethylamine (TMA) and volatile basic nitrogen (VBN) levels, pH values, and color values in/of these parts. The TMA and VBN levels tended to increase during storage and the TMA changes in VPs were higher than those in DPs. In particular, the VP TMA content attained a maximum of 3.68 mg/100 g at 6 days, and the VBN content attained a maximum of 20.88 mg/100 g at 9 days, suggestive of initial fish spoilage. The pH ranged from 5.99-6.17 over the first 3 days and from 6.17-6.38 from days 6-15. Surface color changes on VPs and DPs were explored. Significant decreases in both VP lightness and yellowness were evident after 3 days. The data suggest that both TMA level and lightness of the color are valuable indicators of freshness in the initial stage of mackerel retail.

• Journal of the Korea Concrete Institute
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• v.15 no.4
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• pp.529-540
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• 2003

Recently, the researches on the durability design of concrete structures have been studied. As the examples, models to evaluate the service life prediction of the structure have been developed. The purpose of this article is to develop the model for predicting remaining service life. The final aim is to provide the user time for repairing the concrete structures. In addition, it makes possible to maintain the concrete structure economically. 70 reservoirs out of the inland concrete structures were selected and concrete structures of their components were surveyed. Two methods were used for measuring carbonation; TG/DTA method and Phenolphtalein indicator and, the value of pH was measured by the pH meter, After deriving correlations of calcium carbonate and used year, duration from completion year to 2002, pH value, and concrete cover depth the model was developed for predicting remaining service life by measuring data as small as possible. The conventional models had been developed on the basis of experiment data obtained from the restricted lab environment like as carbon gas exposure. On the other hand this model was developed on the basis of measuring data obtained from the real field that the complex deterioration actions are occurred such as freezing and thawing, carbonation, steel corrosion, and so on. The reliability of the developed model will be evaluated high in this point and this model can help to maintain concrete structures economically by providing the manager time to repair the deteriorated concrete structures in site of facility management.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.3
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• pp.427-432
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• 2005

The purpose of this study was performed as model study using four animals to investigate the correction between the changes in Differential Scanning Calorimetry thermogram of muscle proteins during storage and meat freshness. M. longissimus dorsi of pork was obtained immediately after slaughter and chilled/stored at either $-2^{\circ}C$ or $25^{\circ}C$ for up to 96 h for analyses. DSC thermograms were determined and compared with pH values, ATP-related compounds, K-values, volatile basic nitrogen (VBN) levels, bacterial counts and electrophoretic behavior. Changes in pH, bacterial counts, VBN and K-values were associated with increased storage temperature and time. The levels of pH values, bacterial counts, VBN and K-values of pork samples stored at $25^{\circ}C$ were higher than those of the pork samples stored at $-2^{\circ}C$. ATP concentration decreased faster in samples stored at $25^{\circ}C$. Only IMP increased in samples stored at $-2^{\circ}C$, whereas the concentration of hypoxanthine and inosine increased in samples stored at $25^{\circ}C$. One exothermic peak and two endothermic peaks appeared on the thermograms of pork stored at either temperature. Lower transition temperature of myosin, sarcoplasmic protein and actin peaks were observed. The freshness parameters of K-value, VBN and hypoxanthine showed highly negative correlations (-0.742- -0.9980) to the changes in transition temperature. Therefore, the shift temperature on DSC thermogram can be used as an indicator of the freshness parameters of meat.

• Food Science of Animal Resources
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• v.32 no.4
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• pp.448-457
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• 2012

The predictive ability for off-flavor development and quality change of ground beef was evaluated using a microbial time temperature indicator (TTI). Quality indices such as off-flavor detection (OFD) time, color, pH, volatile basic nitrogen (VBN), aerobic mesophilic bacteria (AMB) counts, and lactic acid bacteria (LAB) counts were measured during storage at 5, 10, 15, and $25^{\circ}C$, respectively. Arrhenius activation energies (Ea) were estimated for temperature dependence. The Ea values for TTI response (changes in titratable acidity (TA)), VBN, AMB counts, LAB counts, and freshness, which is defined based on OFD time for quality indices of ground beef, were 106.22 kJ/mol, 58.98 kJ/mol, 110.35 kJ/mol, 116.65 kJ/mol, and 92.73 kJ/mol, respectively. The Ea of microbial TTI was found to be closer to those of the AMB counts, LAB counts, and freshness. Therefore, AMB counts, LAB counts, and freshness could be predicted accurately by the microbial TTI response due to their Ea similarity. The microbial TTI exhibited consistent relationships between its TA change and corresponding quality indices, such as AMB counts, LAB counts, and freshness, regardless of storage temperature. Conclusively, the results established that the developed microbial TTI can be used in intelligent packaging technology for representing some selected quality indices of ground beef.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.2 no.2
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• pp.139-148
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• 1998

The charge densities of humic acid and humic extract have been determined by back titration using spectrophotometry as the method of end point detection and several cationic polymers of different charge density(copolymers of acylamide and dimethylaminoethylacrylate and polydiallyidimethylammonium chloride, PDDA), and a cationic indicator o-toluidine blue(o-Tb). The charge densities of humic acid and humic extract obtained depend on the charge densities of cationic polymers used. When the polymers of lower charge density are used, lower apparent charge density values are obtained, but for polymers of high charge density(above 2.5 meq/g), the measured values are almost identical, but also are nearly the same as that obtained for PDDA which has a high charge density(about 6 meq/g). For polymers of lower charge density, it is considered that the optimum dosage does not correspond to 1 :1 charge neutralization between anionic and cationic groups. Polymers of high charge density should be used in order to achieve a complete charge neutralization. As humic acid and humic extract are dissociable acids, their ionization is heavily pH dependent and so higher charge density values are obtaines with increasing pH.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.197-202
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• 1998

1-(2-Pyridylazo)-2-Naphthol (PAN) has been widely used as a spectrophotometric reagent and metallochromic indicator for many metal ions. In this work, the chelate reagent of PAN was used as mobile phase additive for the separation of metal ions by reversed phase chromatography. Metal ions could be detected by monitoring the effluent at 570 nm with spectrophotometric detector. In order to investigate retention behaviors of the metal ions, the chromatograms and capacity factors were obtained as the variation of pH, ionic strength and composition of organic modifier in mobile phase. Under the obtained optimum conditions, the mixtures of Fe(III), Ni(II), Cu(II), Zn(II) and Co(II) could be separated successfully and the calibration curves under the recommended conditions showed an excellent linearity. The detection limits(S/N) were feasible at the nanogram level.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1738-1742
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• 2005

In this study a novel triiodide ion-selective electrode based on a charge transfer complex of iodine and Bis(2-hydroxyacetophenone)butane-2,3-dihydrazone (ICT), as a membrane carrier was prepared. The electrode has a linear dynamic range between 1.0 ${\times}$ $10^{-2}$ and 5.0 ${\times}$ $10^{-7}$ M, with a Nernstian slope of 58. 99 ${\pm}$ 0.3 mV $decade^{-1}$ and detection limit of 3.0 ${\times}$ $10 ^{-7}$ M. The potentiometric response of the proposed sensor is independent of the pH of the solution in the pH range of 3.0-10.0. The electrode possesses the advantages of short conditioning time, fast response time, and especially, very good selectivity over a large number of common organic and inorganic anions. The electrode can be used for at least 6 months without any considerable divergences in the potentials. It was used as an indicator electrode in potentiometric titration of triiodide ion with thiosulfate.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.623-625
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• 2000

Bacteriocin-producing lactic acid bacteria was isolated from Kimchi using MRS as selective media and Lactobacillus delbruekii subsp. delbruekii as an indicator strain. Strain JC-3 was tentatively identified as Lactococcus latis subsp. lactis through the API test and the bacteriocin produced by JC-3 showed the inhibitory activity against Grampositive pathogens and other lactic acid bacteria. The antimicrobial substance was inactivated by Protamax, Aroase AP-10, Neutrase, R-AMANO and was confirmed to be heating at $100^{\circ}C$. However, it was lost at high pH values showed the highest bacteriocin activity at a culture temperature of $30^{\circ}C$. The bacteriocin was partially purified by ammonium sulfate precipitation, Sep-pak $C_{18}$ cartridge. The apparent molecular mass of the bacteriocin was about 8 Kda, which was determined through the direct detection of bactericidal activity using SDS -PAGE.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.3 no.2
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• pp.3-16
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• 1996

This study was investigated to the effect of oxygen barrier of four different packaging films of the shelf life of proessed meat product by the simulated distribution test and storage test. The microbial growth, pH, VBN content, TBA value, color change and sensory evaluation were compared during the 2-month storage period at 4, 10, $20^{\circ}C$ after finished the simulated distribution test. The oxygen transmission rates ($cc/m^2$ day) were BF001: 27,88; BF003; 12.30;NY; 77.98; EVOM; 0.41 respectively. The packaging films were not effected on the changes of pH, VBN content, TBA value and color during the storage period. The aerobic microbial growth was increased only at $20^{\circ}C$ in the order of growth rate in the following films;NY > BF001 > BF003 > EVOH. Therefore, the microbial growth was affected significantly by the properties of oxygen barrier off packaging films and it should be an indicator of establishing the shelf life processed meat product.