• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.10a
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• pp.310-315
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• 2004

The objective of this study was to provide the optimum thawing condition under different level of high pressure(50, 100, 150 and 200 MPa) using high pressure assisted technique which can improve the quality of frozen and thawed pork. The calculated thawing rate from the results depending on the high pressure showed the strong trend of increased thawing rate under pressurized condition(P<0.05). And then, the numerical modeling was executed to predict the thawing rate influenced by the pressure level using exponential regression, LnY=0.70623 + 0.00433 ${\cdot}$ P ($R^2=0.9985$), and it was fairly fit for the functional relation between the thawing rate(Y) and pressure(P) with comparatively high coefficient, $R^2$ of determination.

• Food Science of Animal Resources
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• v.29 no.6
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• pp.736-742
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• 2009

This study was conducted to investigate the effect of various high pressure freezing and thawing treatments on the physical properties of pork. To compare the effects of the freezing and thawing process on meat quality, atmospheric freezing followed by running water thawing (AFRT), pressure shift freezing followed by running water thawing (SFRT), and pressure shift freezing and pressure assisted thawing (SFAT) were conducted at pressure of 250 MPa and cooling temperature of $-22^{\circ}C$. SAFT and SFRT showed a shorter phase transition time and total thawing time than AFRT. The pH value of treated samples increased significantly (p<0.05) compared to unfrozen meat. In addition, SFAT and SFRT showed a higher pHvalue than AFRT. Although the water holding capacity was significantly decreased (p<0.05) for SFAT and SFRT, SFRT reduced drip loss. In regards to color, SFAT and SFRT resulted in a significant increase in color parameters (p<0.05) relative to AFRT, while SFAT produced a higher L*-value. High pressure treatment significantly increased shear force (p<0.05) compared to AFRT, and, where SFRT showed the highest shear force. Therefore, these combined results indicated that the hydrostatic pressure treatment improved the functional properties of pork and increased the freezing and thawing rate.

• Food Science of Animal Resources
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• v.27 no.2
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• pp.190-196
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• 2007

This study was carried out to investigate the effects of pressure assisted freezing(PAF) on physicochemical properties of pork meat. Pork meat was frozen under pressure up to 200 MPa at $-60^{\circ}C$, and compared with fresh control. Phase transition temperature decreased with increasing pressure level, while pressure level had no effect on supercooling extent. Increasing pressure level increased pH of meat significantly(p<0.05). Thawing losses of all treatments were significantly higher(p<0.05) than control with the exception of PAF at 200 MPa. Water holding capacity(WHC) was increased significantly(p<0.05) with increasing pressure level up to 100 MPa. Cooking loss tended to decrease with increasing pressure level. In color, CIE $L^*-\;and\;b^*-value$ increased with increasing pressure level, while CIE $a^*-value$ decreased significantly(p<0.05). Increasing pressure level up to 150 MPa increased shear force significantly(p<0.05), however, no significant difference between 150 and 200 MPa in shear force was found(p>0.05). Therefore, the results indicated that excessive pressure level in PAF caused several losses in meat qualities, while PAF at mild pressure level improved meat qualities compared to atmosphere freezing.

• Journal of Embryo Transfer
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• v.27 no.2
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• pp.107-111
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• 2012

Miniature pig sperm cryopreservation is continually researched in biotechnology for breed conservation and reproduction. It is important to control the temperature at each stage of cryopreservation and cryoprotectant. It is also necessary to find the optimal cryoprotectant concentration and chemical elements of the extender. Recently, many studies have used various cryoprotectant materials, such as dimethyl sulphoxide (DMSO), ethylene glycol (EG), antifreeze protein (AFP), amides, and glycerol. Glycerol is a commonly used cryoprotectant. However, glycerol has critical cytotoxic properties, including osmotic pressure and it can cause irreversible damage to live cells. Therefore, We focused on membrane fluidity modifications can reduce cell damage from freezing and thawing procedures and evaluated on the positive effects of trehalose to the viability, chromatin integrity, and motility of boar sperm. Miniature pig sperm was separated from semen by washing with modified- Modena B (mMB) extender. After centrifugation, the pellet was diluted with the prepared first extender. This experiment was designed to compare the effects that sperm cryopreservation using two different extenders has on sperm chromatin. The control group used the glycerol only and it was compared with the glycerol and glycerol plus trehalose extender. Sperm viability and motility were evaluated using WST1 assays and computer-assisted semen assays (CASA). Chromatin structure was examined using acridine orange staining. For the motility descriptors, trehalose caused a significant (p<0.01) increase in total motility ($57.80{\pm}4.60%$ in glycerol vs. $75.50{\pm}6.14%$ in glycerol + trehalose) and progressive ($51.20{\pm}5.45%$ in glycerol vs. $70.74{\pm}8.06%$ in glycerol + trehalose). A significant (p<0.05) increase in VAP ($42.70{\pm}5.73{\mu}m/s$ vs. $59.65{\pm}9.47{\mu}m/s$), VSL ($23.06{\pm}3.27{\mu}m/s$ vs. $34.60{\pm}6.58{\mu}m/s$), VCL ($75.36{\pm}11.36{\mu}m/s$ vs. $99.55{\pm}12.91{\mu}m/s$), STR ($54.4{\pm}2.19%$ vs. $58.0{\pm}1.63%$), and LIN ($32.2{\pm}2.05%$ vs. $36.0{\pm}2.45%$) were also detected, respectively. The sperm DNA fragmentation index was 48.8% to glycerol only and 30.6% to glycerol plus trehalose. Trehalose added group showed higher percentages of sperm motility, stability of chromatin structure than glycerol only. In this study, we suggest that trehalose is effective in reducing freezing damage to miniature pig sperm and can reduce chromatin damage during cryopreservation.