• Korean journal of food and cookery science
• /
• v.33 no.2
• /
• pp.148-154
• /
• 2017

Purpose: Frozen Korean traditional rice cakes (Sulgitteok and Garaetteok) were evaluated different conditions ($-20^{\circ}C$ and $-10^{\circ}C$) freezing (magnetic resonance quick freezing and air blast freezing) to study differences in quality characteristics. Methods: Experiments analyze Korean rice cakes for water content, water activity, color, textural properties, and sensory characteristics. Results: Moisture content showed high value at $-20^{\circ}C$ freezing regardless of freezing method. Water activity was higher at $-20^{\circ}C$ than $-10^{\circ}C$, and water activity higher magnetic resonance quick freezing than air blast freezing. The lightness values were higher $-20^{\circ}C$ freezing temperature compare to $-10^{\circ}C$ freezing temperature. Hardness and chewiness were the lowest $-20^{\circ}C$ magnetic resonance quick freezing. sensory evaluation both Sulgitteok and Garaetteok showed better overall acceptability at $-20^{\circ}C$ magnetic resonance quick freezing. Conclusion: Therefore, the $-20^{\circ}C$ magnetic resonance quick freezing method resulted in favorable textural properties and sensory characteristics.

• Restorative Dentistry and Endodontics
• /
• v.34 no.6
• /
• pp.491-499
• /
• 2009

This study examined the influence of the storage methods on the viability of oral epithelial cells using conventional cell freezing storage, slow freezing preservation, rapid freezing preservation, and slow freezing preservation with a pressure of 2 Mpa or 3 Mpa. The cell viability was evaluated by cell counting, WST-1 and the clonogenic capacity after 6 days of freezing storage. After 6 days, the frozen cells were thawed rapidly, and the cell counting. WST-1, and clonogenic capacity values were measured and compared. 1. The results from cell counting demonstrated that conventional cryopreservation, slow freezing under a 2 Mpa pressure and slow freezing under a 3 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p < 0.05). 2. The results from the optical density by WST-1 demonstrated that slow freezing under a 2 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p<0.05). 3. The clonogenic capacity demonstrated that slow freezing under a 2 Mpa pressure showed significantly higher values than slow freezing preservation and rapid freezing preservation (p < 0.05).

• Journal of Advanced Marine Engineering and Technology
• /
• v.21 no.5
• /
• pp.527-534
• /
• 1997

Freezing of an aqueous sodium cWoride solution (Nacl- H20) saturating a packed bed with ini¬tial salt concentrations of 5, 10, 15(k by weight is investigated experimentally in a rectangular cav¬ity. The system was cooled from the top, bottom and a vertical side wall. For the freezing experi¬ments from below, there was little effect of the initial salt concentration throughout the freezing process, and the global freezing rate was not affected by the initial salt concentration. For the freezing from above, the size of the mush region decreased and the mushlliquid interface became flatter as the initial liquid concentration is decreased. For the freezing from vertical side wall, reheating of the mixture was intensified with an increase in the initial salt concentration. For Ci= 5%, supercooling was observed only at the early times of freezing process, but for Ci= 15% small supercooling was observed throughout the freezing process.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.5
• /
• pp.680-686
• /
• 1998

In the adoption of a desalination system the most important factor is the cost of fresh water pro-duction. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$ When it is serviced however the LNG absorbs energy from a heat source and it is transformed to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energycan be utilized to produce fresh water by using a sea water freez-ing desalination system. in order to develop a sea water freezing desalination system and to estab-lish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water in a cooled circular tube to measure the freezing rate and to investigate the freezing heat-transfer characteristics. The experimental results provide a general understanding of sea water freezing behavior in a cooled circular tube.

• Journal of Biosystems Engineering
• /
• v.33 no.1
• /
• pp.21-29
• /
• 2008

In this study, the thermal properties of peeled chestnuts were measured, and the mathematical prediction model of freezing time was also developed for various interior positions from center to rind (surface). The measured thermal properties were showed that heat conductivity is $0.43W/m^{\circ}C$, specific heat is $2.7206J/m^3^{\circ}C$, latent heat is $216.9{\times}10^6J/m^3$ and freezing point is $-2.8^{\circ}C$. The entire process about reaching to the freezing time of peeled chestnuts was analyzed with its each regular depth position using the finite difference method (FDM) based on computer simulation. In case of regular freezing temperature, it was showed an that surface (rind) position is more rapidly reached into the freezing point rather than the center position, and also reaching time to the freezing point is more fast at the lower freezing temperature. Comparison results between simulation and experiments showed linear relationship. In regularly varying condition for freezing temperature, this method would give an information to predict a freezing time of the interior points for peeled chestnuts and more similar agricultural products.

• Food Science of Animal Resources
• /
• v.36 no.5
• /
• pp.650-655
• /
• 2016

This study investigated the effects of artificial supercooling followed by still air freezing (SSF) on the qualities of pork loin. The qualities of pork frozen by SSF were compared with the fresh control (CT, stored at 4℃ for 24 h), slow freezing (SAF, still air freezing) and rapid freezing (EIF, ethanol immersion freezing) treatments. Compared with no supercooling phenomena of SAF and EIF, the extent of supercooling obtained by SSF treatment was 1.4℃. Despite that SSF was conducted with the same method with SAF, application of artificial supercooling accelerated the phase transition (traverse from -0.6℃ to -5℃) from 3.07 h (SAF) to 2.23 h (SSF). The observation of a microstructure indicated that the SSF prevented tissue damage caused by ice crystallization and maintained the structural integrity. The estimated quality parameters reflected that SSF exhibited superior meat quality compared with slow freezing (SAF). SSF showed better water-holding capacity (lower thawing loss, cooking loss and expressible moisture) and tenderness than SAF, and these quality parameters of SSF were not significantly different with ultra-fast freezing treatment (EIF). Consequently, the results demonstrated that the generation of supercooling followed by conventional freezing potentially had the advantage of minimizing the quality deterioration caused by the slow freezing of meat.

• Journal of Advanced Marine Engineering and Technology
• /
• v.22 no.4
• /
• pp.529-537
• /
• 1998

Currently as due to the rapid development of industry and increase in population we meet serious problems concerning the shortage and pollution of water. In the country many experts predict a shortage of water approaching 450 million tons by the year 2006. To cope with this serious problem it is necessary to construct desalination plants. In the adoption of a desalination system the most important factor is the cost of fresh water production,. In general LNG is stored in a tank as a liquid state below $-162^{\circ}C$. When it is serviced, however the LNG absorbs energy from a heat source and transforms to a high pressure gaseous state. During this process a huge amount of cold energy accumulated in cooling LNG is wasted. This wasted cold energy can be utilized to produce fresh water by using a sea water freezing desalination system. In order to develop a sea water freezing desalination system and to establish its design technique qualitative and quantitative data regarding the freezing behavior of sea water is required in advance, The goals of this study are to reveal the freezing behavior of sea water is required in advance. The goals of this study are to reveal the freezing mechanisms of sea water to measure the freezing rate and to investigate the freezing heat-transfer characteristics,. The experimental results will provide a general understanding of sea water freezing behavior in a rectangular vessel cooled from above.

• Clinical and Experimental Reproductive Medicine
• /
• v.27 no.3
• /
• pp.283-289
• /
• 2000

Objective: The study was performed to compare the survival rate and the development of day 2 mouse embryos which had freezing procedures done. Methods: We used three different vitrification solutions (EFS, VS14, DPS) and a ultrarapid freezing solution (UFS) for cryopreservation of day 2 mouse embryo. Results: We tested toxicity by exposing embryos to vitirification solutions and a ultrarapid freezing solution. The survival rates are 100%, 97.8%, 95.6% and 100% (EFS, VS14, DPS and UFS). After cultured for 96 hours, hatching rates of each group are 93.5% (no freezing), 95.6% (EFS), 86.4% (VS14), 93.0% (DPS), and 93.0% (UFS). There is no significant differences among groups. The survival rates after thawing cryopreserved embryos are 80.2%, 91.7%, 69.5%, 0% and 91.8% (slow freezing, EFS, VS14, DPS and UFS). Also cultured for 96 hours, the hatching rates are 93.5% (no freezing), 84.1% (slow freezing), 93.9% (EFS), 48.5% (VS14) and 70.1% (UFS). Conclusion: The survival rates of vitrification in EFS solution and ultrarapid freezing are higher than slow freezing (p<0.05). The hatching rate of vitrification in EFS solution cultured for 96 hours is highest, so vitrification of day 2 mouse embryos in EFS solution considered as more effective for cryopreservation.

• International Journal of Highway Engineering
• /
• v.7 no.2 s.24
• /
• pp.87-95
• /
• 2005

To prevent the lowering of structural capability due to freezing and thawing in cold winter, numerous researches on frost heaving have been performed. As the result, the freezing index contour map of the Korea peninsula has been made for the design of the anti-freezing layer of pavements. However, the validity of the anti-freezing layer needs to be evaluated because systematic investigations on the variation of freezing depth with the thickness and material types of pavement layers and the configuration of the ground have been rarely performed. The freezing index of the Korea Highway Corporation test road site was calculated and the freezing depths of the concrete and asphalt pavements of the test road were investigated using the ambient and pavement temperature and water content. In addition, the investigated freezing depths were compared to the values estimated by existing freezing depth models. This is the preliminary study on the freezing-related data measured at the test road. The results with higher reliability will be produced by the long-term accumulation of the data and the analysis on it.

• Korean Journal of Food Science and Technology
• /
• v.20 no.2
• /
• pp.280-286
• /
• 1988

Freezing is becoming incressingly important in the food industry as a means of food preservation since the turn of the century. For quality, processing and economic reasons, it is important to predict the freezing time for foods. A number of models have been proposed to predict freezing time. However, most analytical freezing time prediction techniques apply only to specific freezing conditions. Therefore, it is necessary to develop an improved analytical method for freezing time prediction under various conditions. The objectives of this study, by reviewing previous experimental data obtained by uncertain freezing condition and thermo-physical data, were to develop simple and accurate analytical method for prediction freezing time, and to obtain the freezing time of various foodstuffs by still air freezing and immersion freezing method. The result of this study showed that the proposed method offered better results than the other complex method compared.