• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.23-30
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• 1995

This study was undertaken to clarify the effects of electrical stimulation on physicochemical and rheological properties of the plaice (Paralichthys olivaceus) muscle at early period after death. The plaices were electrically stimulated in seawater bath (110V/60Hz) for 15sec., 35sec., and 60sec. and killed instantly with spiking at the head. Killed samples were stored at $5^{\circ}C$, and the changes in rigor index, ATP breakdown, lactate accumulation, and breaking strength of muscle through storage were investigated. Electrical stimulation effectively accelerated rigor-mortis, lactate accumulation , and ATP breakdown. As the time of electrical stimulation was lengthened, the onset of rigor-mortis of all samples were accelerated Just after killing, and the amount of lactate was rapidly increased, But, significant differences were not observed in variance of rigor-mortis and lactate concentration. Electrically stimulated plaices showed decreasing in ATP to $4.58{\mu}mole/g$ for 15sec., $4.13{\mu}mole/g$ for 35sec., and $2.39{\mu}mole/g$ for 60sec. samples as compared with $5.5{\mu}mole/g$ of unstimulated samples. As the time of electrical stimulation was lengthened, ATP in samples were decomposed more rapidly. The rate constant of ATP breakdown were $0.244hr^{-1}$ for 15sec., $0.358hr^{-1}$ for 35sec., and $0.479hr^{-1}$ for 60sec.. The level of breaking strength in muscle of the plaice was $1050.30\pm50.23g$ immediately after killing. Values of breaking strength in samples electrically stimulated for 35sec. increased rapidly just after killing among all samples. However, the breaking strength was not increased through the whole storage time in samples stimulated for 60sec.. The value and time roaching to the maximum breaking strength for each samples stimulated electrically for 15, 35 and 60 second were $1264.43\pm35.76g$ and 2hr, $1357.68\pm22.50g$ and Ohr, and $1012.18\pm57.36g$ and Ohr. Breaking strength in all samples electrically stimulated decreased significantly (P<0.05) after reaching the maximum values.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.700-707
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• 2013

The purpose of this study was to monitor physicochemical changes of olive flounder (Paralichthys olivaceus) muscle by iced water pre-treatment. Moisture content, crude fat content, nucleotide content, texture (hardness and toughness), and rigor mortis were assessed. The sensory evaluation was performed with a nine-point hedonic test. K-values, a parameter of fish flesh freshness, were also calculated from the content of nucleotides and their corresponding decomposition products. Pre-treatment of flounder flesh with iced water was found to be fresher compared to the control, as determined by a difference in the K-values. Iced water pre-treatment hastened postmortem stiffness, as judged from the rigor index, and increased inosine monophosphate (IMP), which is known to be a savory taste compound, more quickly as adenosine triphosphate (ATP) degradation proceeded.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.33-41
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• 1984

To obtain the fundamental data on the nutritional value of protein for fresh meat, it was per- formed the distribution of Tl(trypsin indigestible substrates) and the apparent in vitro protein digestibility in 8 species of dark-fleshed fishes and8 species of white-fleshed fishes which were consumed in Korea popularly. It was also investigate the changes in VBN and TBA value during frozen storage at $-10^{\circ}C$on the purpose of assaying the antinutritional factors that affect on apparent in vitro protein digestibility or Tl forming. Tl content in dark-fleshed fishes were varied with their species, ranged from 0.02 to 0.17 mg/g. using the method by Hamerstrand, while that in white-fleshed fishes was almost same, ranged from 0.10 to 0.26 mg/g. For all the fresh fish samples, however, the apparent in vitro protein digestibility were showed the value from 83 to 83%. In comparison with the parts of pacific mackerel, viscera had the most abundant Tl content as much as 0.3m g/g, while a trace was noted for skin and dark muscle had more Tl content than ordinary muscle based on the method by Hamerstrand. The apparent in vitro protein digestibility for all samples was dropped but the changes of VBN and TBA were retested the similar tendency with the increasing Tl content during frozen storage at $-10^{\circ}C$. Therefore, it could be concluded that Tl contbnt and apparent in vitro protein digestibility were affected by its freshness and fat oxidation and that, especially, fat was assumed to play an important role on apparent in vitro protein digestibility.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.87-94
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• 2011

To find the preliminary environmental conditions for a short-time transport of living olive flounder, Paralichthys olivaceus, the stress response and physiological metabolic activity of the cultured fish to feed deprivation and slow temperature descending ($15.8^{\circ}C{\rightarrow}13.3^{\circ}C$) were monitored for 8 days. The monitored variables were the plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), glucose (GLU), total protein (TP), electrolytes ($Na^+$, $K^+$, $Cl^-$) and thyroid hormones ($TT_4$, $TT_3$, $FT_4$ and $FT_3$). In food deprivation experiment for 8 days, we did not find any statistical change of level in AST, ALT and electrolytes ($Na^+$, $K^+$, $Cl^-$), but found a significant decrease in TP and GLU. In thyroid hormones, the levels of four hormones in plasma were all showing a tendency to decrease. Especially, $FT_4$ and $TT_3$ were significantly decreased, indicating a withering of physiologic activity. In the temperature test, although no any significant change in AST, TP and electrolytes ($Na^+$, $K^+$, $Cl^-$), we observed a significant decrease of ALT and GLU following to temperature descending from $15.8^{\circ}C$ to $13.3^{\circ}C$ (P<0.05). In the levels of thyroid hormones, any significant change was not observed for experimental period. We conclude that the stress response and physiological activity of olive flounder were more influenced by feed deprivation than slow temperature descending at a transport of living fish, and plasma GLU appears to be sensitive factor to physiological metabolic activity, indicating that it could be used as a monitering mark or index for a health inspection of the fish.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.51-68
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• 2019

This study performs to evaluate adaptability of seashore filtering type seawater-intake which adapts dua1 filter well alternative for direct seawater-intake. This study varies filter condition of seashore free surface aquifer which is composed of sand layer then installs real size dual filter well and single filter well to evaluate water permeability and proper pumping amount according to filter condition. According to result of step aquifer test, it is analysed that 110.3% synergy effect of water permeability coefficient is happened compare to single filter since dual filter well has better improvement. dual filter has higher water permeability coefficient compare to same pumping amount, this means dual filter has more improved water permeability than single filter. According to analysis result of continuous aquifer test, it is evaluated that dual filter well (SD1200) has higher water permeability than single filter well (SS800) by analysis of water permeability coefficient using monitoring well and gauging well, it is also analysed dual filter has 110.7% synergy effect of water permeability coefficient. As a evaluation result of pumping amount according to analysis of water level dropping rate, it is analysed that dual filter well increased 122.8% pumping amount compare to single filter well when water level dropping is 2.0 m. As a result of calculating proper pumping amount using water level dropping rate, it is analysed that dual filter well shows 136.0% higher pumping amount compare to single filter well. It is evaluated that proper pumping amount has 122.8~160% improvement compare to single filter, pumping amount improvement rate is 139.6% compare to averaged single filter. In other words, about 40% water intake efficiency can be improved by just installation of dual filter compare to normal well. Proper pumping amount of dual filter well using inflection point is 2843.3 L/min and it is evaluated that daily seawater intake amount is about $4,100m^3/day$ (${\fallingdotseq}4094.3m^3/day$) in one hole of dual filter well. Since it is possible to intake plenty of water in one hole, higher adaptability is anticipated. In case of intaking seawater using dual filter well, no worries regarding damages on facilities caused by natural disaster such as severe weather or typhoon, improvement of pollution is anticipated due to seashore sand layer acts like filter. Therefore, It can be alternative of environmental issue for existing seawater intake technique, can save maintenance expenses related to installation fee or damages and has excellent adaptability in economic aspect. The result of this study will be utilized as a basic data of site demonstration test for adaptation of riverside filtered water of upcoming dual filter well and this study is also anticipated to present standard of well design and construction related to riverside filter and seashore filter technique.