• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1684-1691
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• 2021

In this study, the physicochemical changes related to fishy smell were determined by storing high hydrostatic pressure (HHP)-treated mackerel (Scomber japonicus) meat in a refrigerator for 20 days. The inhibition of crude urease activity from Vibrio parahaemolyticus using HHP treatment was also investigated. The mackerel meat storage experiment demonstrated that production of trimethylamine (TMA) and volatile basic nitrogen (VBN), the main components of fishy smell, was significantly reduced on the 20th day of storage after the HHP treatment compared to the untreated mackerels. The results demonstrated that the increased ammonia nitrogen rates in the 2000, 3000, and 4000 bar, HHP-treated groups decreased by 23.8%, 23.8%, and 31.0%, respectively, compared to the untreated groups. The enzyme activity of crude urease was significantly reduced in the HHP-treated group compared to that in the untreated group. Measurement of the volatile organic compounds (VOCs) in mackerel meat during storage indicated that the content of ethanol, 2-butanone, 3-methylbutanal, and trans-2-pentenal, which are known to cause off-flavor due to spoilage, were significantly reduced by HHP treatment. Collectively, our results suggested that HHP treatment would be useful for inhibiting the activity of urease, thereby reducing the fishy smells from fish and shellfish.

• Food Science of Animal Resources
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• v.41 no.2
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• pp.185-195
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• 2021

The objective of this study was to determine the effects of high pressure to investigate the technical functional properties of the protein solution extracted from an edible insect, Protaetia brevitarsis seulensis. High pressure processing was performed at 0 (control), 100, 200, 300, 400, and 500 MPa at 35℃. The essential amino acid index of the control was lower (p<0.05) than that of the P. brevitarsis seulensis extract treated with 100 MPa. The SDS-PAGE patterns tended to become faint at approximately 75 kDa and thicker at approximately 37 KDa after high pressure treatment. The protein solubility and pH of the protein tended to increase as the hydrostatic pressure levels increased. The instrument color values (redness and yellowness) of the P. brevitarsis seulensis protein treated with high pressure were lower (p<0.05) than those of the control. The forming capacity of the protein solution with P. brevitarsis seulensis treated with high pressure was higher (p<0.05) than that of the control. In conclusion, we confirmed that the technical functional properties of edible insect proteins extracted under high pressure of 200 MPa are improved. Our results indicate that high pressure can improve the technical functional properties of proteins from edible insects.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1423-1430
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• 2014

This study investigated the effects of superheated steam (SHS) and high hydrostatic pressure (HHP) on the quality of Galbijjim. SHS cooking increased moisture and crude fat contents and decreased crude protein contents (P<0.05). The value of L was significantly higher upon SHS cooking compared to conventional cooking (CC), whereas a and b values were not significantly different among the samples. Hardness decreased more upon CC than SHS. The results of the safety storage experiment at refrigeration temperature showed that the total number of bacteria was lower in SHS-HHP than in CC-HHP. The thiobarbituric acid value increased to 0.70~1.56 mg malonaldehyde (MA)/kg in CC-HHP after 15 days, and SHS-HHP showed 0.69 (0 day)~1.24 (15 days, $10^{\circ}C$) mg MA/kg. Volatile basic nitrogen value was 18.07~36.76 mg% in CC-HHP, and that in SHS-HHP also increased to 17.06 (0 day)~35.76 mg% (15 days, $10^{\circ}C$). Overall, SHS cooking and HHP reduced microorganisms, which could improve product quality and sanitation.

• Development and Reproduction
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• v.13 no.4
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• pp.291-296
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• 2009

In most larvae of ascidian, two sensory pigment cells, otolith and ocellus, lie in their brain vesicle. They also have a third type of sensory cells: hydrostatic pressure receptor (Hpr) cells. The Hpr cells were presumed to be hydrostatic pressure-detection cells, but their precise functions is still disputed. In this study, we investigated whether an FGF signaling is involved in formation of Hpr cells. When fertilized eggs were injected with Hr-FGF9/16/20 antisense MO, the resulting larvae showed severe abnormalities with no expression of the Hpr cell-specific Hpr-1 antigen. Similar results were obtained using an FGF receptor inhibitor, SU5402, and an MEK inhibitor, U0126. Embryos treated with SU5402 or U0126 during the 32-cell and hatching stages did not express the Hpr-1 antigen. To elucidate the temporal requirement for the FGF signaling in formation of Hpr cells, embryos were treated with SU5402 for 2 h, or U0126 for 20 min during various embryonic stages. Larvae treated with SU5402 from the 16-cell stage to the 64-cell stage did not express the Hpr-1 antigen, whereas those treated at the early gastrula stage expressed the Hpr-1 antigen. When U0126 treatment was carried out at various stages between the 8-cell and late gastrula stages, larvae scarcely formed the Hpr cells. They showed expression of the Hpr-1 antigen when embryos were placed in U0126 just before the neural plate stage. These results suggest that FGF9/16/20 signaling is involved in formation of Hpr cells from the primary neural induction stage to the late gastrula stage.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.133-140
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• 2010

This study was carried out to investigate the changes of ginsenoside contents and antioxidative activities from red ginseng after treated with high hydrostatic pressure (RGHHP). Crude saponin content in traditional red ginseng (TRG) and RGHHP were 21.93 and 27.29 mg/g, respectively. The contents of total phenolics, crude saponin and ginsenoside increased after treated with high hydrostatic pressure. TRG and RGHHP showed an increase 25.60% the highest content of Rb1 (14.10 mg/g and 17.71 mg/g). Also, Rg3 content compared with TRG and RGHHP increased 10.46%. The radical scavenging activity of hot water extract from red ginseng against the DPPH and ABTS radicals increased with the increasing amount of extract and RGHHP higher than TRG. The reducing power and ferric reducing antioxidant power (FRAP) assays of the red ginseng were increased in a dose dependent manner. The FRAP of TRG and RGHHP were 0.30 and 0.36 absorbance, respectively at a concentration of 10 mg/mL. The present results suggest that RGHHP would have the protective potential from oxidative stress induced by free radicals.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.10
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• pp.1131-1137
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• 2012

Subsea pipelines have been operated with buried depths of 1.2-4m underneath the seabed to prevent buoyancy and external impacts. Therefore, they have to show resistance to both the soil load and the hydrostatic pressure. In this study, the structural integrity of a subsea pipeline subjected to soil load and hydrostatic pressure was evaluated by using FE analyses. A parametric study showed that the internal pressure increased the plastic collapse depth by increasing the resistance to plastic collapse. The hoop stress increased with an increase in the buried depth for the same water depth; however, the hoop stress decreased with an increase in the water depth for the same buried depth.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.198-201
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• 2004

To investigate hydrostatic pressure (HP) effect on myofibrillar protein (Mf) extracted from bovine Semitendinosus muscle, Ca- and Mg-ATPase activities to evaluate denaturation of myosin and actin, and soluble protein contents were observed. In Mf treated with 100 MPa for 5 min was not observed denaturation of myosin and actin. In Mf treated with 200 MPa for 5 min, denaturation of myosin and actin were observed but inactivation rate was low (0.0136 $min^{-1}$). Inactivation rate of myosin and actin was dramatically increased above 300 MPa treatment. However denaturation of myosin and actin was not that critical with duration time. By increasing pressure size, the amount of myosin and actin in soluble protein eluted in 20 mM potassium phosphate buffer (pH 7.0) containing 0.6 M NaCl were decreased. SDS-PAGE of soluble protein released from Mf suspension in 0.1 M NaCl buffer (pH 7.0) showed that low molecular weight proteins (15${\sim}$36 KDa) were released by HP treatment above 200 MPa. From the results, denaturation of myosin and actin, and release of light molecule proteins of Mf were observed by HP treatment over 200 MPa.

• Journal of Drive and Control
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• v.11 no.3
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• pp.31-40
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• 2014

This paper proposes a multi absorbing wave energy converter design, in which a hydrostatic transmission is used to transfer wave energy to electric energy. The most important feature of this system is its combination of the pressure coupling principle with the use of a hydraulic accumulator to eliminate the effects of wave power fluctuation; this maintains a constant speed of the hydraulic motor. Tilt motion of a floating buoy was employed as the power take-off mechanism. Furthermore, a PID controller was designed to carry out the speed control of the hydraulic motor. The design offers some advantages such as extending the life of the hydraulic components, increasing the amount of energy harvested, and stabilizing the output speed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.4
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• pp.469-476
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• 1983

The effects of oil supply conditions on the static and dynamic properties of journal bearings supporting high speed rotors were investigated. The initially unknown hydrostatic pressure in oil pockets were determined by iteration with the aid of the equation of oil flow balance for given oil supply pressure and flow coefficients of oil inlet. For the calculation of dynamic characteristics, the dynamic changes of pressure in lubricating gaps and oil pockets were linearised with a perturbation method.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.3
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• pp.1057-1062
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• 1991

본 연구에서는 형상을 미소하게 변화시켜 좌굴을 방지할 수 있는 최적 도움형 상을 설계하였고 타원형, 토리-구형도움의 가장 얕은 형태의 최적도움형상도 설계하였] 으며, 실제 적용예를 수치로 제시하였다. 또한 수압(hydrostatic pressure)을 받는 수조(reservoir)의 도움형상에 대해서도 직경 및 길이 변화에 따른 형상설계 결과를 제시하였다.