• 한국가축번식학회지
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• 제16권3호
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• pp.217-224
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• 1992

These studies were carried out ot investigate on the transferred embryo development following ultrarapid frozen for 8-cell and morula of in vitro fertilization mouse embryos. The post-thaw embryo survival was evaluated and compared by cell stage of embryos and by equilibration time before ultrarapid freezing. The results obatined were summerized as follows: 1. The effects of equilibration time of 3 vs. 6 minutes before ultrarapid freezing and after thawing on the morphological survival and the viability of 8-cell and morulas embryos were not significant. 2. When the ultrarapid frozen-thawed 32 eight-cell and 33 morula embryos, and 30 fresh blastocysts were transferred to pseudopregnant recipient mice, the number of normal offsprings produced were 9(28.1%), 14(42.4%) and 18(60.0%), respectively. From the above resutls, it was concluded that the optimal conditions of pH osmolality of the media for mouse IVF and embryo culture, and the period of sperm preincubation might be 7.1, 310 mOsm and 120 min., respectively,a nd somewhat high conception rate might be resulted from transfer of frozen embryos of morula stage and fresh embryos of blastocyst stage.

• 한국가축번식학회지
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• 제8권1호
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• pp.22-28
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• 1984

This experiment was carried out to investigate effects of DMSO or ethylene glycol as a cryopotectant and of freezing methods on survival rate of forozen-thawed rat 2-cell embryos by morphological observation. 2-cell embryos were recovered from oviducts of Sprague Dawley females mated with males of same strain on day 2 of pregnancy after inducing superovulation by intrapertioneal injection of PMSG and HCG. In slow freezing and thawing groups, embryos were frozen to -79$^{\circ}C$ or -196$^{\circ}C$ in a glass test tube containing 0.2ml PBI with 1.5M DMSO or 1.2M ethylene glycol at a rate of 0.3-1.0C/min. and thawed slowly. When samples were frozen to -79$^{\circ}C$, higher survival rate was obtained in the medium containing DMSO (43.9%) than ethylene glycol (41%). And similar result was obtained (32.5% in DMSO vs. 31.4% in ethylene glycol) when samples were frozen. In rapid freezing and thawing groups, embryos were frozen to -79 or -196$^{\circ}C$ in a glass test tube containing 0.2ml of PBI with 1.5M DMSO or 1.2M ethylene glycol by rapid cooling, and thawed rapidly. When samples were frozen to -79$^{\circ}C$, 1.5M DMSO (13.2%) was more effective than 1.2M ethylene glycol (6.1%). When the storage temperature was -196$^{\circ}C$, survival rates were 9.8% in 1.5M and 5.4% in 1.2M ethylene glycol.

• 한국식품영양과학회지
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• 제19권2호
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• pp.107-114
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• 1990

The keeping quality of seasoned mackerel meat products during frozen storage were investi-gated for the effective utilization of mackerel as a food source. The pH and volatile basic nitrogen (VBN) contents of products revealed a tendency to increase slightly during frozen storage,. Viable cell counts(1.5$\times$104-2.0$\times$104/g) and histamine contents(2.45-2.89mg/100g) were decreased during frozen storage. In fatty acid composition of the products polye-nes such as 22:6, 18:3, 20:4 and 20:5 were the maincomponents. From the results of chemical experiments and sensory evaluation the products could preserved with good quality during frozen storage(-$25^{\circ}C$) of 120 days.

• 한국식품조리과학회지
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• 제21권2호
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• pp.217-224
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• 2005

The storage characteristics of frozen soy yogurt prepared with hydrolyzed soy protein isolates were evaluated. In order to facilitate lactic fermentation bacteria grow and produce lactic acid as fast rate as possible, soy protein isolate(SPI) was hydrolyzed using two kinds of proteases; bromelain and a-chymotrypsin. The cultural systems employed thereafter for lactic fermentations were Bifidobacterium bifidum or B. bifidum and Lactobacillus bulgaricus. The viable cell counts, normal- and bile acid tolerances from the mixed cultures of B. bifidum and L. bulgaricus decreased sharply during the initial first 3 days of frozen storage and then showed a gradual decrease thereafter. Melt-down percent of the all frozen products have been favorably affected as was shown by less melting at raised testing temperature during 28 days of frozen storage except for the initial 3 days during which a minor change has been observed. Among the various volatile flavor components, the contents of acetaldehyde, acetone, diacetyl and methanol generally increased during the frozen storage. In sensory test, the frozen soy yogurt prepared with a-chymotrypsin and mixed culture of B. bifidum and L. bulgaricus was the most desirable, the highest scores in sourness, bitterness and mouthfeel.

• 한국수정란이식학회지
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• 제27권4호
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• pp.253-258
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• 2012

This study was carried out to effects of ethylene glycol concentration, sucrose and culture day of in vitro production embryo on slow-down freezing in Hanwoo. 6, 7, 8 and 9 day embryos produced in vitro were frozen using 1.8M EG+0.1M sucrose, 1.8M EG+0.5% BSA and 1.5M EG+0.1M sucrose media. Survivability was confirmed after frozen-thawed 24 and 48h and ICM, TE cell number were counted by Hoechst 33342 and PI staining after frozen-thawed 24h. As a result, 1.8M EG+0.1M sucrose group was most significantly (p<0.05) higher compared with the other treatment groups on survivability, TE and total cell number after frozen-thawed 24h ($94.2{\pm}2.6%$, $94.67{\pm}3.4$ and $129.67{\pm}5.5$). ICM number did not found significant (p<0.05) differences between the three treatment groups. in 6, 7, 8 and 9 day of embryos using three types of freezing media, frozen-thawed, 1.8M EG+0.1M sucrose groups with embryos cultured 8 day was significantly (p<0.05) highest survivability to $98.3{\pm}1.7%$ after frozen-thawed 24h. 1.5M EG+0.1 sucrose group with embryos cultured 9 day was significantly higher survivability than group of embryos cultured 8 day after frozen-thawed 24 and 48h. In conclusion, 1.8M EG+0.1M sucrose media is considered to be effective to cryopreservation of embryos cultured 8 and 9 day.

• 한국식품조리과학회지
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• 제20권6호
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• pp.658-666
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• 2004

In order to develop and commercialize high quality frozen soy yogurt, the effects of industrial proteases and commercial mixed cultures were examined on the functional properties and the sensory attributes of frozen soy yogurt. For quality improvement, soy protein isolates were primarily hydrolyzed by either Flavourzyme or Neurtrase, industrial Proteases, to reduce the beany flavor and increase the functional properties of the protein. The viable cell count of lactic acid bacteria was higher in the soy protein hydrolysates than whenuntreated. ABT-5 (L. acidophilus, Bifidobacterium lactis, and S. thermophilus) resulted in higher acid tolerance, bile acid tolerance and melt-down percent values than those with YC-X11 (Lactobacillus bulgaricus and Streptococci thermophilus). The overrun of frozen soy yogurt was improved by both Flavourzyme $(193.3\%)$ and Neurtrase $(156.7\%)$ treatments. With regard to thesensory characteristics, Flavourzyme improved the beany flavor, astringency taste, mouth feel and overall quality of frozen soy yogurts fermented with ABT-5. Further studies onproduct formulation will be needed to commercialize the frozen soy yogurt for the market.

• Geomechanics and Engineering
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• 제19권2호
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• pp.193-199
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• 2019

A frozen fringe plays a key role in frost heave development in soils. Previous studies have focused on the physical and mechanical properties of the frozen fringe, such as overall hydraulic conductivity, water content and pore pressure. It has been proposed that the thickness of the frozen fringe controls frost heave behavior, but this effect has not been thoroughly evaluated. This study used a temperature-controllable cell to investigate the impact of frozen fringe thickness on the characteristics of frost heave. A series of laboratory tests was performed with various temperature boundary conditions and specimen heights, revealing that: (1) the amount and rate of development of frost heave are dependent on the frozen fringe thickness; (2) the thicker the frozen fringe, the thinner the resulting ice lens; and (3) care must be taken when using the frost heave ratio to characterize frost heave and evaluate frost susceptibility because the frost heave ratio is not a normalized factor but a specimen height-dependent factor.

• 한국가축번식학회지
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• 제26권4호
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• pp.311-320
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• 2002

The objective of this study was to assess the developmental potential in vitro produced embryos frozen-thawed with the various containers, and also examined expression and localization of heat shock protein 70 at these embryos. For the vitrification, 2-cell, 8-cell and blastocyst stage embryos produced by in vitro fertilization (IVF) and nuclear transfer (NT) were exposed the ethylene glycol 5.5 M freezing solution (EC 5.5) for 30 sec, loaded on each containers such EM grid, straw and cryo-loop, and then immediately plunged into liquid nitrogen. Thawed embryos were serially diluted in sucrose solution, each for 1 min. and cultured in CRI-aa medium. Survival rates of the vitrification production were assessed by re-expanded, hatched blastocysts. There were no differences in the survival rates of IVF using EM grid and cryo-loop. However, survival rates by straw were relatively lower than other containers. The use of cryo-loop resulted in only survival of nuclear transferred embryos (43.7%). Also, there embryos after IVF or NT were analysed by semi-quantitive reverse transcription-polymerase chain reaction (RT- PCR) methods for hsp 70 mRNA expression. Results revealed the expression of hsp 70 mRNh were higher thawed embryos than control embryos. Immunocytochemistry used to localize the hsp 70 protein in embryos. Two and 8-cell embryos derived under control condition was evenly distributed in the cytoplasm but appeared as aggregates in some frozen-thawed embryos. However, in the control, blastocysts displayed aggregate signal while Hsp70 in frozen-thawed blastocysts appeared to be more uniform In distribution. Therefore, this result suggests that the exploiting Hsp 70 in the early embryos may be role for protection of stress condition for increase viability of embryos within IVF, NT and there frozen-thawed embryos.

• 한국수정란이식학회지
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• 제12권1호
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• pp.11-20
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• 1997

The influence of cryopreservation of donor embryos on the in vitro developmental potential in the nuclear transplant rabbit embryos was evaluated. The embryos of 16-cell stage were collected and cryopreserved with EFS solution by vitrification method. The frozen embryos were thawed and synchronized to S and G$_1$ phase of 32-cell stage. The recipient/ cytoplasms were obtained by removing the first polar body and chromosome mass from the oocytes collected by non-disruptive microsurgery procedure. The separated S and G$_1$ phase blastomeres of 32-cell stage were injected into enucleated recipient cytoplasms by micromanipulation. After culture until 20 hrs post-hCG injection, the nuclear transplant oocytes were electrofused and activated by electrical stimulation. The fused nuclear transplant embryos were co-cultured with rabbit oviduct epithelial cells. After in vitro culture for 120 hrs, the nuclear transplant embryos developed to blastocyst stage were stained with Hoechst 33342 dye and their blastomeres were counted. The electrofusion rate was significantly (P<0.05) reduced in the frozen nuclear donor,compared with fresh donor nuclei as 80.0 vs 62.8% in S phase and 81.7 vs 64.8% in G$_1$phase, respectivley. The in vitro developmental rate to blastocyst stage with the S and G$_1$phase of fresh embryos(26.3 and 61.1%, respectively) was found significantly (P<0.05) higher, compared to the S and G]phase of frozen embryos(11.9 and 34.6%, respectively). When frozen as well as fresh donor embryos were synchronized to G$_1$ phase, the in vitro developmental rate to blastocyst stage was significantly (P<0.05) higher, compared with S phase donor nuclei. The cell counts of nuclear transplant embryos developed to blastosyst stage were significantly (P<0.05) more in G$_1$ phase of fresh or frozen embryos (180.1 and 125.7 cells, respectively), compared with S phase nuclear donor (145.1 and 103.7 cells, respectively). From the above results it was concluded that the rabbit embryos cryo- preserved by vitrification might be available as nuclear donor, though the developmentalpotential and cell counts of nuclear transplant rabbit embryos were decreased significantly.

• Preventive Nutrition and Food Science
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• 제1권2호
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• pp.252-255
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• 1996

As an index of freeze-injury of yeast, the leakage of intracellular substances from yeast cells after freeze-thawing was investigated. It was found that much more ultraviolet-absorbing substances leaked out from non-freeze tolerant yeast (NETY) than from freeze-tolerant yeast. Furthermore, the rate of leakage of cellular substances form NFTY during incubation exceeded that of FTY, indicating that NFTY is more susceptible to freeze-injury than FTY during frozen-storage. An apparent degradation of phospholipid was observed during incubation of perfermented frozen-cells of NFTY, while little change of phospholipid occurred in FTY, These results suggested that the difference in the sensitivity of yeast might be due to the strength of cell membrane in terms of the degradation of phospholipid by enzymes, phospholipases, attached to cell membranes.