• Food Science and Preservation
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• v.6 no.4
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• pp.398-401
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• 1999

This study was conducted to investigate the changes in qualities of soft persimmon by freezing and defrosting. Testing varieties were Sangjudungsi and Chunsdobansi that were cultivated on Sangju and Chungdo regions, chief cultivation of astringent persimmon in Kyongbuk province. Dropping time to 40 degrees below zero of the flesh was 10∼20 minutes longer in Chungdobansi than that in Sangiudungsi. Freezing temperature of astringent persimmon was 2∼3 degrees below zero. Occurence rates of cracked fruit during freezing storage were 24.5% in Sangjudungsi and 15.5% in Chungdobansi. Defrosting of Sangjudungsi and Chungdobansi took 150 minutes and 120 minutes at 5$^{\circ}C$, respectively. L values of chromaticity were some lower after defrosting than that of frozen soft persimmon, and a and b values decreased during defrosting rapidly. Soluble solid contents of frozen soft persimmon almost didn't change during freezing, that is, harvesting, softening, frosting and defrosting steps. Defrosting completion time to core part took 4 hours and 30 minutes in Sangjudungsi and 4 hours and 20 minutes in Chungdobansi at ordinary temperature (10.9∼14.8$^{\circ}C$).

• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.57-64
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• 2010

Objectives: Likewise fresh cycle, it is also important to select right blastocysts for transfer in purpose of improving the pregnancy and implantation rates in frozen-thawed embryo transfer (ET) cycles. To investigate the relationship between the developmental velocity at the time of cryopreservation and pregnancy rates, we compared pregnancy rates between the day 5 cryopreservation group and the day 6 cryopreservation group. Methods: Transfers of frozen-thawed blastocysts which had been cryopreserved by vitrification on day 5 or day 6 were performed between January 2006 and June 2007. Ethylene glycol, DMSO, and pull and cut straws were used for vitrification and artificial shrinkage was done in expanded blastocysts. Thawing was performed on the day before transfer and thawed blastocysts were cultured in for 15~18 hrs in Quinn's blastocyct media. Blastocyst survival was assessed before transfer and post-thaw survival was defined as >50% of cells remaining intact and blastocoele re-expansion by the time of transfer. Results: Transfers of thawed blastocyst had been cryopreserved on day 5 were 52 cycles and 41 transfer cycles were cryopreserved on day 6. Patient characteristics, the number of transferred embryos and the survival rate of thawed blastocysts were not different in each cryopreservation day. But the biochemical pregnancy, clinical pregnancy, ongoing pregnancy, and implantation rate were significantly high in transfer of frozen-thawed blastocyst which were cryopreserved on day 5. Conclusions: The clinical pregnancy and implantation rate of day-5 blastocyst showed significantly higher than those of day-6 blastocyst in frozen-ET cycles. This result indicated that developmental rate of blastocyst at cryopreservation time in frozen-thawed cycle is discriminative marker of pregnancy outcome as like in fresh cycle.

• Food Science and Preservation
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• v.19 no.2
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• pp.201-208
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• 2012

The sensory properties of $Kalopanax$ $pictus$ and $Cedrela$ $sinensis$ shoots were analyzed according to their blanching conditions and the thawing methods used. For the Hunter colors, the $K.$ $pictus$ that was blanched without adding salt for 6 min had the highest L value, and the $C.$ $sinensis$ that was blanched with 1% salt for 6 min had the highest L value. The chlorophyll content of $K.$ $pictus$ was 141.1 mg% when it was blanched for 3 min with 2% salt, and the chlorophyll content of $C.$ $sinensis$ that was blanched without adding salt for 6 min was highest (124.8 mg%). When $K.$ $pictus$ and $C.$ $sinensis$ were blanched without salt addition for 3 min, their texture showed a higher value than that of the other samples. The sensory test result showed the highest overall preference for the sample that was blanched without adding salt for 3 min, among all the samples. The L value of the $K.$ $pictus$ that was thawed in a microwave oven was significantly higher than that of the other samples, but the L value of the $C.$ $sinensis$ that was thawed at $4^{\circ}C$ was higher than that of the other samples. As for the overall preference for the samples according to the thawing method used, $K.$ $pictus$ and $C.$ $sinensis$ scored highest in the case of thawing in a microwave oven.

• Journal of Food Hygiene and Safety
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• v.31 no.1
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• pp.42-50
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• 2016

The effects of freezing and thawing conditions on microbiological quality and microstructure change of inoculated (Listeria monocytogenes and Campylobacter jejuni) and non-inoculated chicken breasts were investigated. Chicken breasts were frozen with air blast freezing (-20, -70, and $-150^{\circ}C$), ethanol ($-70^{\circ}C$) and liquid nitrogen ($-196^{\circ}C$) immersion freezing. There were no significant differences on the populations of L. monocytogenes inoculated with chicken breasts under different freezing conditions. However, air blast freezing ($-20^{\circ}C$) resulted in significant reductions for total aerobic bacteria and C. jejuni compared to the control and other freezing treatments. The frozen samples were thawed with (hot or cold) air blast, water immersion, and high pressure thawing at $4^{\circ}C$ and $25^{\circ}C$. the populations of total aerobic bacteria, and yeast and mold in the frozen chicken breast increased by 5.78 and 4.05 log CFU/g after water immersion thawing ($25^{\circ}C$) treatment. After five freeze-thaw cycles, the populations of total aerobic bacteria, yeast and mold, and C. jejuni were reduced by 0.29~1.40 log cycles, while there were no significant differences (P > 0.05) in the populations of L. monocytogenes depending on the freeze-thaw cycles. In addition, the histological examination of chicken breasts showed an increase in spacing between the muscle fiber and torn muscle fiber bundles as the number of freeze-thaw cycles increased. These results indicate that freezing and thawing processes could affect in the levels of microbial contamination and the histological change of chicken breasts.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.29-33
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• 2021

Purpose Plasma renin activity (PRA) test is important for the diagnosis of primary aldosteronism. PRA is an easily deformed substance in vitro and affected by temperature changes. Laboratory of ASAN medical center has consistently found that there was a difference between the initial and re-experimental results. We compared and analyzed the differences in PRA test results according to the sample storage status. Materials and Methods The measurement of PRA was performed by using the radioimmunoassay. From August to September 2020, 43 PRA re-test samples were tested with different sample storage condition. The first group was re-examined by freezing the plasma-separated samples at -18℃, and the second group was re-examined with refrigerated EDTA sample. Also, additional tests were conducted on 13 PRA samples to verify the effect on thawing temperature differences in plasma-separated samples. The same samples were divided into two parts and stored frozen at -18℃, respectively, and thawing samples in room temperature and those in refrigerator were were conducted. Each result was compared and analyzed based on the initial experimental results. Results The results of re-examination after frozen storing plasma separation samples showed a lower correlation than the results of re-examination with EDTA plasma samples in refrigerator. When calculating the percentage based on the initial test results, the average percentage of each was 404.9% and 133.8%. The correlation coefficient was also R=0.8501 and R=0.9966, respectively, showing a higher correlation between plasma in the refrigerated sample EDTA tube. In comparison experiments with differences in thawing temperature, average percentage of the results of initial test and room temperature thawing was 94.3% and the average percentage of the results of refrigerated thawing was 88.0%. After again freezing the sample, the average percentage of the second room temperature thawing result is 107.5%, and the second refrigerated thawing group is 112.7%. Both groups showed an increase from first thawing. Conclusion A comparative analysis of retesting according to differences in sample storage methods in PRA tests showed a higher correlation between the results of retesting of the refrigerated EDTA plasma. And repeated freezing and melting of plasma separation samples, regardless of temperature during defrosting, has been shown to affect results. Therefore, retest of PRA should re-collect plasma from original EDTA plasma to increase reproducibility.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2006.05a
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• pp.175-178
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• 2006

냉동하여 해동한 한우육은 냉장 쇼케이스에서 진열 판매하는 동안 육색소의 산화가 촉진되어 변색이 빠르게 이루어진다. 그 이유는 냉동과 해동이라는 물리적인 충격에 의해 근육세포 내의 효소체계가 파괴되어 MetMb 환원력이 감소한 겉과 MetMb 형성이 증가하기 때문인 것으로 사료된다.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2004.05a
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• pp.229-232
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• 2004

해동육은 신선육에 비해 냉장저장 중 지방산화와 관계없이 육색소 산화가 촉진된다. 그 이유는 냉동 및 해동이라는 외부 및 물리적인 충격에 의해 근육세포 내에 증가된 HADH가 MetMb 형성에 영향을 미친 결과로 사료된다.

• Food Science of Animal Resources
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• v.20 no.4
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• pp.282-287
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• 2000

동결기간과 해동 후 재냉장이 우육의 기호성에 미치는 영향을 검토하기 위하여 도축 후 1일 냉장한 홀 스타인 등심육을- 2$0^{\circ}C$에 동결하여 20, 40 및 60일째에 해동하는것과 이것을 1$^{\circ}C$에 재냉장한 것의 전단력가, 부수성, 액토미 오신의 추출성과 ATPase 활성에 대한 실험과 함께 관능평가를 실시하였다. 우육의 전단력가능 동결 중 변화가 없었으며 해동 후 재냉장에 의하여 낮아졌다. 부수성은 동결기간이 길수록 낮아지고 재냉장에 의한 유의적인 차이를 보이지 않았다. 액토미오산의 추출성과 Ma-ATP-ase 활성은 동결기간이 길수록 낮아지고 재냉장에 의하여 높아지고 경향을 보였다. 재냉장에 의한 기홍성 향상 효과는 동결기간이 짧을수록 크게 나타났다. 재냉장에 의하여 기호성이 우수하게 된 것은 조직감과 가열육향의 향상이 크게 관련되었다.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.6
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• pp.923-931
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• 2010

Effects of freezing period and chilling process after thawing on the physicochemical properties and palatability of hind shank meat from Korean native beef were investigated. There were no significant differences in the Hunter's color, volatile basic nitrogen (VBN) or collagen amount of hind shank meat upon freezing with vacuum packing at $-20^{\circ}C$ for 9 months. In addition, while pH, thiobarbituric acid (TBA) value, hardness, drip and boiling loss of hind shank meat increased and palatability decreased, there significant difference were observed only after 9 months. Softness, water holding capacity, L-glutamic acid, oleic acid, and polyunsaturated fatty acid contents increased upon chilling for 4 days after thawing, and there was a significant increase in palatability. The values of VBN and TBA increased markedly upon 6 days of chilling after thawing, and there was a significant decrease in palatability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1492-1503
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• 2015

This study evaluated the combination effect of various freezing and thawing techniques on the quality and nutritional aspects of onions. Onions were frozen by natural air convection freezing (NCF), air blast freezing (ABF), and liquid nitrogen freezing (LNF). Onions were frozen for 76 min by NCF, 9 min by ABF, and 9 min by LNF. The freezing treatment was stopped when the core temperature reached $-12^{\circ}C$ for NCF and ABF, and $-120^{\circ}C$ for LNF. Frozen samples were thawed through natural air convection thawing, running water thawing, sonication thawing (ST), or microwave thawing. The quality and nutritional aspects of frozen-thawed onions were evaluated by measuring thawing loss, pH, texture, water content, color, and SEM image. ST was found to cause the least loss in onion sample among the tested thawing methods, whereas the freezing methods did not cause any significant loss. In our experiment, thawing is found to be a more critical technique when compared to that of freezing. There were no clear quantifications or trends of pH and water content among different freezing and thawing techniques. The highest total color difference (${\Delta}E$) was observed in the NCF sample. For morphological observation, ABF gave the smallest ice crystal size, as well as minimum cell collapse. Loss of vitamin C, free sugar, and organic acid content was lower in the ABF and ST sample, when compared to other trials. In our study, we found that combination of ABF and ST could preserve the quality and nutritional aspects of frozen-thawed onions better than other methods.