• The Korean Journal of Food And Nutrition
• /
• v.31 no.1
• /
• pp.135-142
• /
• 2018

We investigated the influence of germination and high hydrostatic pressure (HHP) treatment conditions on the conversion of functional compounds and antioxidant activity in adzuki bean. The adzuki bean germinated at $25^{\circ}C$ for three- or six-days, and was later subjected to HHP at 0.1, 50, 100, or 150 MPa for 24 h. The highest polyphenol content (5.36 mg gallic acid equivalents (GAE)/g) and flavonoid content (0.91 mg catechin equivalents (CE)/g) were observed after germination for six days and HHP treatment at 100 MPa for 24 h, respectively. The total phenolic acid contents increased with increasing applied pressure from 88.86 to $208.26{\mu}g/g$ (100MPa, 24h). Phenolic acids are divided into two categories; those that exhibit increased content upon HHP treatment, and those that exhibit decreased content. The increasing phenolic acids were gallic acid, chlorogenic acid, (+)-catechin, ${\rho}-coumaric$ acid, ferulic acid, heperidin, salicylic acid, protocatechuic acid, cinnamic acid, naringenin. The total anthocyanin content decreased with increasing applied pressure from 22.42 mg/100 g to 6.28 mg/100 g (150 MPa, 24 h). The highest ABTS radical scavenging activity (8.02 mg eq AA/g) and DPPH radical scavenging activity (1.22 eq Trolox/g) were observed after germination for six days and HHP treatment at 100MPa for 24h, respectively. These results suggested that the combination of HHP and germination can lead to improved functionality in adzuki bean.

• Food Engineering Progress
• /
• v.13 no.2
• /
• pp.85-91
• /
• 2009

High hydrostatic pressure and enzymatic hydrolysis (HPEH) was applied to anchovy in order to produce a natural seasoning ingredient. Total soluble solid, amino nitrogen, total nitrogen and the degree of hydrolysis of anchovy hydrolysates were investigated depending on the process parameters such as temperature, pressure, enzyme concentration and enzyme type. The optimal condition for anchovy hydrolysis was confirmed as temperature 50$^{\circ}C$, reaction time 24 hrs, pressure 50 MPa and enzyme concentration 0.6% in HPEH treatment. HPEH treatment showed more effective in overall properties of anchovy hydrolysis than those of control. All anchovy hydrolysates produced by HPEH treatment were increased more 1.5-2.6 times of total free amino acid than that of control. From these results, the HPEH treatment appears to be an effective and economic process to produce a natural seasoning ingredients.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
• /
• 2001.06a
• /
• pp.2122-2122
• /
• 2001

The ultra-high pressure technology fur the preservation of foods is under intense research to evaluate its potential as an alternative or complementary process to traditional methods of food preservation. Traditional processing methods usually need a large amount of energy, may cause unwanted reactions in the food, leading to cooked flavor and loss of vitamins, etc. The application of ultra-high hydrostatic pressure for food processing consists of subjecting the food to pressures in the range of 100-1000 ㎫. The ultra-high pressure inactivates the microorganisms and some enzymes, promotes the germination of spores and extends the shelf-life of the foods. This new technology follows the “minimal processing” concept minimizing the quality degradation, saving the vitamins, essential nutrients and flavors as well as utilizing less energy. We joined the research team at our University involved in the mentioned technology using an ultra-high pressure equipment, recording of the near infrared spectra and signal response of a chemosensor array (electronic nose) of their meat (beef and pork), vegetable and fruit samples exposed to different pressure. The results of our investigations achieved by evaluating the measured data using PCA and PQS methods will be presented.

• Tribology and Lubricants
• /
• v.36 no.3
• /
• pp.153-160
• /
• 2020

In this paper, we present a hydrostatic bearing design and rotordynamic analysis of a pump-and-drive turbine module for a 250-kW supercritical CO₂ cycle application. The pump-and-drive turbine module consists of the pump and turbine wheel, assembled to a shaft supported by two hydrostatic radial and thrust bearings. The rated speed is 21,000 rpm and the rated power is 143 kW. For the bearing operation, we use high-pressure CO₂ as the lubricant, which is supplied to the bearing through the orifice restrictor. We calculate the bearing stiffness and flow rate for various orifice diameters, and then select the diameter that provides the maximum bearing stiffness. We also conduct a rotordynamic analysis based on the design parameters of the pump-and-drive turbine module. The predicted Campbell diagram shows that there is no critical speed below the rated speed, owing to the high stiffness of the bearings. Furthermore, the predicted damping ratio indicates that there is no unstable mode. We conduct the operating tests for the pump and drive turbine modules within the supercritical CO₂ cycle test loop. The pressurized CO₂, at a temperature of 136℃, is supplied to the turbine and we monitor the shaft vibration during the test. The test results show that there is no critical speed below the rated speed, and the shaft vibration is controlled to below 3 ㎛.

• The Korean Journal of Food And Nutrition
• /
• v.31 no.6
• /
• pp.836-843
• /
• 2018

The objective of this study was to determine the effect of high hydrostatic pressure (HHP) treatment on proliferation of human cancer cell lines (MCF-7, HCT-116, PC-3 and AGS) of crude soyasaponin extracts in germinated black soybean. Black soybean was germinated and subjected to HHP, followed by preparation of crude soyasaponin extracts. Cell treatments done with extracts less than $400{\mu}g/mL$ concentrations had no significant effect on 3T3-L1 adipocyte cell viability. The inhibitory effect of crude soyasaponin extracts with germination periods and applied pressure on breast cancer cell (MCF-7), human colon cancer cell (HCT-116), human gastriccancer cell (AGS) and prostate cancer cell (PC-3) growth were investigated using MTT assay. The highest anti-proliferation of human cancer cell line of crude soyasaponin extracts was observed at 150 MPa treatment after germination for 4 days (150 MPa-Day 4). The cell viability on MCF-7, HCT-116, PC-3 and AGS cell lines of crude soyasaponin extract in 150 MPa-Day4 was 48.82%, 57.37%, 39.89% and 23.94% at $400{\mu}g/mL$, respectively. These results suggest that soyasaponin extracts from black soybean subjected to HHP after germination may mediate physiological activity.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2007.05a
• /
• pp.83-85
• /
• 2007

Deep-sea bacteria are adapted to extreme environments, such as high pressures and cold temperatures. We have isolated many piezophiles which grow well even under high pressures from deep-sea sediment. Shewanella violacea DSS12 and Moritella japonica DSK1 have the ability to grow at up to 70 MPa, and those bacteria have unique mechanisms of gene expression in response to high pressure conditions. The combination of gene expression systems in piezophiles, like the high pressure-dependent promoters and GFP reporter gene, may reveal highly fluorescent cells when exposed to high hydrostatic pressure conditions. It is predicted that a novel bio-sensing system can be made to probe high pressure environments using living bacteria. First, gene transformation into our piezophiles, strains DSS12 and DSK1, were examined. Eschericha coli S17-1 was used for bacterial conjugation with those piezophiles. As a result, the broad host range vector, pKT231, and the shuttle vector, pTH10, were successfully introduced to DSS12 and DSK1, respectively. Next, The pressure regulated promoters from DSS12 and DSK1 were cloned into proper vectors and combined with GFP as a reporter gene downstream of each promoter. The transformants of DSK1 and DSS12 with the recombinant pTH10 and pKT231 plasmid, which has cadA and glnA promoters (each of them is a pressure regulated promoter from DSK1 and DSS12, respectively) and GFP, were grown under high pressure and gene expression of GFP promoted by 50 MPa pressure was confirmed. This is a critical point to create a pressure-sensing bacteria, as the "High Pressure Glow Cells", which will indicate the level of environmental pressure using fluorescence of GFP as a reporter gene.

• Food Science and Biotechnology
• /
• v.18 no.4
• /
• pp.861-866
• /
• 2009

Effects of pressure come-up and holding times on the inactivation of Salmonella enterica and Listeria monocytogenes were evaluated in deionized water, milk, orange juice, and tomato juice with pH 6.76, 6.85, 3.46, and 4.11, respectively. The inoculated samples were subjected to high pressure treatments at 300, 400, and 500 MPa for less than 10 min at $30^{\circ}C$. At 500 MPa, the numbers of S. enterica and L. monocytogenes in deionized water, orange juice, and tomato juice were reduced by more than 6 log CFU/mL during the come-up time. Compared to orange and tomato juices, milk showed a considerable baroprotective effect against S. enterica and L. monocytogenes. At 300 MPa, the D values for S. enterica in milk, orange juice, and tomato juice were 0.94, 0.41, and 0.45 min, while those for L. monocytogenes were 9.56, 1.11, and 0.94 min, respectively. Low pH resulted in a noticeable synergistic effect on the inactivation of S. enterica and L. monocytogenes in orange and tomato juices. Therefore, these results might provide more useful information for designing the entire high hydrostatic pressure (HHP) conditions, taking the come-up time reduction, and food system.

• Geomechanics and Engineering
• /
• v.37 no.2
• /
• pp.179-187
• /
• 2024

In this paper, a unified time-dependent constitutive model of Darcy flow and non-Darcy flow is proposed. The influencing factors of flow velocity are discussed, which demonstrates that permeability coefficient is the most significant factor. Based on this, the dynamic evolution characteristics of water inrush during tunneling through fault fracture zone is analyzed under the constant permeability coefficient condition (CPCC). It indicates that the curves of flow velocity and hydrostatic pressure can be divided into typical three stages: approximate high-velocity zone inside the fault fracture zone, velocity-rising zone near the tunnel excavation face and attenuation-low velocity zone in the tunnel. Furthermore, given the variation of permeability coefficient of the fault fracture zone with depth and time, the dynamic evolution of water flow in the fault fracture zone under the variable permeability coefficient condition (VPCC) is also studied. The results show that the time-related factor (α) affects the dynamic evolution distribution of flow velocity with time, the depth-related factor (A) is the key factor to the dynamic evolution of hydrostatic pressure.

• Food Science and Preservation
• /
• v.6 no.4
• /
• pp.521-529
• /
• 1999

The high influx of imported fruits into Korea is threatening to price and quality competition of domestic fruits. This investigation was conducted to raise price and quality competition of domestic fruits and to develop new products. The scale of production and processing, amount of processing and new processing technology were discussed. The area of cultivation land as well as the rate of processing is decreasing annually, an item of processing is limited to several kinds. Accordingly in this study, the status of production and manufacturing of some fruits and the new processing technologies such as high voltage pulsed electric fields, high hydrostatic pressure, ohmic heating, membrane separation and microwave treatment have investigated to fruit processing. Consequently, the minimal processing technology has to take advantage of various agricultural products in the food industry.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.11
• /
• pp.1441-1446
• /
• 2012

An axial-piston-type hydraulic motor involves friction and leakage losses at the sliding parts, contact loss at the mechanism assembly parts, volumetric loss caused by the pressure drop, housing oil churning loss and compressibility from the hydraulic oil pipe resistance, etc. the friction and volumetric loss at the hydrostatic bearing between the piston shoe and the swash plate rotating at high speed and having an oil film gap of 8-15 ${\mu}m$ strongly affects the total efficiency of the hydraulic motor. In this study, a variable swash-plate-type hydraulic piston motor operating under a maximum pressure of 35 MPa, maximum speed of 2,500 rpm, and displacement of 320 cc/rev is tested to verify the optimal ratio of the hydrostatic bearing which is closely related to the hydraulic motor performance.