• Food Science of Animal Resources
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• v.36 no.2
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• pp.283-288
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• 2016

The objective of this study was to investigate the microbial count of duck meat and duck meat products commercially available in Korea. High hydrostatic pressure (HHP) treatment was applied at 0.1, 300, 400, and 500 MPa for 5 min to enhance the microbiological safety of duck meats. The levels of total aerobic bacteria were in the ranges of 3.53-6.19 and 3.62-6.85 Log CFU/g in raw and smoked duck products, respectively. By DNA sequence analysis, we identified microorganisms responsible for spoilage, with the most common species in the raw and smoked duck products being Aeromonas spp. or Pseudomonas spp. and Leuconostoc mesenteroides, respectively. HHP treatment significantly reduced the levels of total aerobic bacteria in raw and smoked duck products. This study demonstrates that HHP treatment may be used to effectively improve the safety of raw and smoked duck meat products.

• Journal of Ginseng Research
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• v.44 no.1
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• pp.154-160
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• 2020

Background: Korean ginseng (Panax ginseng Meyer) powder is in rising demand because powder forms of foods are convenient to handle and are highly preservable. However, ginseng powder (GP) manufactured using the conventional process of air drying and dry milling suffers nutrient destruction and a lack of microbiological safety. The objective of this study was to prepare GP using a novel process comprised of UV-TiO₂ photocatalysis (UVTP) as a prewashing step, wet grinding, high hydrostatic pressure (HHP), and freeze-drying treatments. Methods: The effects of UVTP and HHP treatments on the microbial population, ginsenoside concentration, and physiological characteristics of GP were evaluated. Results: When UVTP for 10 min and HHP at 600 MPa for 5 min were combined, initial 4.95 log CFU/g-fw counts of total aerobes in fresh ginseng were reduced to lower than the detection limit. The levels of 7 major ginsenosides in UVTP-HHP-treated GP were significantly higher than in untreated control samples. Stronger inhibitory effects against inflammatory mediator production and antioxidant activity were observed in UVTP-HHP-treated GP than in untreated samples. There were also no significant differences in CIELAB color values of UVTP-HHP-treated GP compared with untreated control samples. Conclusion: Combined processing of UVTP and HHP increased ginsenoside levels and enhanced the microbiological safety and physiological activity of GP.

• 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.

• 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.

• 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.

• Journal of Drive and Control
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• v.19 no.1
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• pp.34-42
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• 2022

Hydrostatic transmission (HST) comprises rotary parts, shafts, valve plate, swashplate, and servo pistons. Ensuring structural stability of each part of an HST has a significant impact on product safety. In this study, the structural stability of HST in agricultural machinery and industrial vehicles was analyzed using ANSYS software. For conservative evaluation, high-pressure conditions (35.5 MPa and 2 MPa pilot pressure) were applied as load conditions. The number of grids used in the calculations ranged from 0.4 to 0.8 million depending on modeling requirements. Structural analysis was performed for essential parts and safety factor was analyzed. All major parts of HST had a safety factor of ≥ 1.5. Thus, they were judged to be structurally safe. This study provides important information for designing an HST system.

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.111-116
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• 2000

Effects of ultra-high pressure treatment on viable cell count and quality characteristics of low salt fermented anchovy under different operating conditions such as pressure$(200{\sim}500\;MPa)$, temperature$(20{\sim}50^{\circ}C)$ and treatment time$(5{\sim}20\;min)$ were investigated. Viable cell count decreased gradually with the increase of pressure and suddenly at 400 MPa. It also decreased by seven folds at $50^{\circ}C$ and logarithmically with the increase of treatment time. Peroxide value increased with the increase of pressure, temperature and treatment time, and temperature played a major role. Thiobarbituric acid value was higher by two folds in samples treated than in the untreated regardless of any conditions investigated. Volatile basic nitrogen was almost the same in all samples except the one at $50^{\circ}C$. The sample treated at greater than $30^{\circ}C$ under high hydrostatic pressure indicated higher value in amino nitrogen. Treatment at $20^{\circ}C/300$ MPa/15 min showed greater reductions in viable cell counts, remaining better quality of low salt fermented anchovy.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1989.11a
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• pp.94-99
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• 1989

This paper analyzes file stiffness, damping coefficient, friction force and flow coefficient of externally pressurized oil journal beating, including the effect of journal rotation according to the Sommerfeld number. This paper assumed that the oil in the whole pocket has constant pressure, and that the oil in the whole bearing region has constant viscosity, temperature and density. Reynolds equation is derived from Nuvier - Stokes equation and continuity equation. And solved bearing pressure by ADI method for whole bearing region and fitted with out flow rate of pocket region. The model for numerical simulation is hydro - static oil journal bearing for high-speed, high-accuracy lathe spindle.

• Journal of Photoscience
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• v.9 no.2
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• pp.82-85
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• 2002

33kDa extrinsic protein, an important protein in oxygenic photosynthesis, was known to have no fixed configuration in solution. At 20$\^{C}$ and pH 6, 33kDa extrinsic protein showed changes of free energy of -14.6 kJ/mor$\^$-1/ and of standard volume of -120mL/mol, respectively, with increase of hydrostatic pressure, comparatively lower than for most proteins. NBS modification of Trp241 in 33kDa extrinsic protein dramatically changes the secondary protein structure, its affinity to photosystem II as well as photosynthetic oxygen evolution. The relationship between structural change and transport of oxygen, water and proton is deserved a further study.

• 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.