• Food Science and Preservation
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• v.14 no.5
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• pp.469-473
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• 2007

The optimal formula for non-frozen pound cake was sought using a central composite design with a quadratic model, by response surface methodology (RSM). Behavior on supercooling, freezing time, theological properties, and sensory attributes of pound cake were studied by using various concentrations of sugar, sorbitol, and glycerol. The freezing temperature of standard pound cake was $-16.16^{\circ}C$. The hardness, freezing point temperature, and sensory properties were shown as a quadratic relationship whereas moisture content was analyzed by a linear model. Optimized formula for non-frozen cake were suggested to include (sugar:sorbitol:glycerol) 77.6:0.0:20.4, 60.0:32.8:16.4, and 70.8:11.2:19.6 (all % of total sugar) by RSM. The freezing tines of optimized non-frozen pound cake were reduced by $27{\sim}45%$. The freezing Points of optimized pound cake were depressed below $-20^{\circ}C$. Sorbitol and glycerol may be used as cryoprotectants and preserve the desired sensory attributes of pound cake at low temperatures.

• Applied Microscopy
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• v.37 no.3
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• pp.175-183
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• 2007

The Drosophila retinal cell is widely used to study cell development and cell signaling processes. In the past decades, conventional chemical fixation had been used to study the structure of retinal cells in Droscphila. Rapid freezing methods are superior to chemical fixation methods due to their fixation speed. Some Drosophila tissues, such as the eyes, should not be freezed due to their surrounding cuticle layer. Therefore, in the case of the Drosophila retina, the benefits of high pressure freezing and freeze substitution (HPF-FS) had not been verified. In this study, a retinal cell from Drosophila melanogaster had been studied by using the HPF-FS method. Compared to chemical fixation, the preservation of the cytoplasm in the HPF-FS sample was improved on the whole. The HPF-FS cell membranes were smoother than that of chemical fixation. In addition, HPF-FS preserved the mitochondria structures very well. These results of the present study suggest that HPF-FS is superior to other fixation methods for the preservation of the retinal cell structure.

• Journal of Sericultural and Entomological Science
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• v.34 no.1
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• pp.1-7
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• 1992

For a long-term preservation of silkworm stocks by frozen gonad storage, fundamental topics such as freezing rate and transplanting stage of the gonad, proper cryoprotectant, and super-cooling temperature and freezing point of the freezing medium were examined and following results were obtained. Proper method to anesthetize the ovary-recipient silkworm was to dip the animal to cold water for 10 minutes, and the ovary taken from the 4th instar larvae was more suitable for freezing-preservation than that from the 5th. Concerning the cryoprotectant, glycerol and DMSO were effective to prevent cryoinjury of the ovary, but sorbitol was not. The supercooling temperature and freezing point of the medium to freeze the ovary and testes were checked, and consulting with the results desirable cooling rate was confirmed. On the desirable conditions of transplanting methods, freezing rate and cryoprotectant concentration ect., the next generation was obtained when the females implanted frozen-thawed ovaries mated with normal males, but none of the normal females mated with the males implanted frozen-thawed testes laid fertilized eggs. Now it is needed to improve the connecting ration of the ducts associated with the transplanted testis to those of the hosts.

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.30-36
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• 1991

The method of vitnilcation has various merits. It needs neither seeding nor slow freezing. It can freeze embryo by putting it directly into liquid nitrogen at the indoor temperature to $0^{\circ}C$. The operation process is quite easy. Moreover, higher promise of survival can be expected as there is no physical damage by any lumps of ice with the exception of cells. In Kasal's experiment (1990) using EFS liquid and Kang's experiment (1991) using GFS liquid the ratio of the damaged embryo was only 2-3%. But, the method of vitrification is now on the process of improvement, and the final or united method is not yet established. At the present time, most of the major institutes all over the world are using the traditional freezing method in the preservation of mouse embryo, but it is very likely that the vitrification will prevaIl in the near future considering the various merits of it. Calves can be begotten from the embryo by means of vitriilcated preservation in the cases of cow, rat, and rabbit as well as of mouse. In addition, recent experiments have shown that vitrificated preservation was successful in the case of drosophila embryo which was much bigger than mammalian embryo, which fact tells that this method is expected to be preferably used even in the preservation of living organs in the near future.

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

• Food Science and Preservation
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• v.10 no.2
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• pp.125-130
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• 2003

This study was carried out to investigate the thermo-physical properties and design Freezing time prediction model from data of freezing test of Kimchi. Density of Kimchi were measured as 1001.9 ${\pm}$0.03 kg/㎥ at unfrozen state, 987.0 ${\pm}$0.07 kg/㎥ at frozen state and volume of the Kimchi expanded 4.67% at -l5$^{\circ}C$. Initial freezing point of Kimchi and seasoning were -4.0$^{\circ}C$ and -2.5$^{\circ}C$, respectively. Freezing ratio of Kimchi were estimated more than 50％ at -5.0$^{\circ}C$, more than 75% at -l0$^{\circ}C$ and approximately 90% at -25$^{\circ}C$. To obtain equation for freezing time prediction of Kimchi, freezing time(Y) was regressed against the reciprocal( $X_3$) of difference of initial freezing point and freezing medium temperature, reciprocal( $X_4$) of surface heat transfer coefficient, the initial temperature( $X_1$) and thickness( $X_2$) of samples. As results of the multiple regression analysis, equations were obtained as follows. Y$_{kimchi}$=3.856 $X_1$+13982.8 $X_2$+8305.166 $X_3$+ 3559.181 $X_4$-639.189( $R^2$=0.9632). These equations shown better results than previous models, and the accuracy of its was very high as average absolute difference of about 10% in the difference between the fitted and experimental results.

• Korean journal of food and cookery science
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• v.32 no.6
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• pp.665-676
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• 2016

Purpose: This study was conducted to find the optimal freezing method and storage conditions for welsh onion. Methods: Cut welsh onions (0.3 cm) were packed in nylon/linear low density polyethylene (LLDPE) film bags, and frozen utilizing still-air freezing at -$20^{\circ}C$ (SAF20) and -$40^{\circ}C$ (SAF40), and immersed-liquid freezing at -$40^{\circ}C$ (ILF40); they were then stored at -$20^{\circ}C$ for 7 months. During storage, quality characteristics were measured monthly. Results: Drip loss was the lowest in the ILF40 packaging. Color difference in the stem (white part) did not differ significantly according to freezing conditions and storage time. Color difference in the leaf (green part) and stem was the lowest in SAF20. pH remained unchanged, while total aerobic bacterial count, pyruvic acid and moisture content decreased during storage. Pyruvic acid content of ILF40 was the highest among the freezing treatments. Fructose and glucose contents increased gradually during storage. Citric acid, malic acid, succinic acid and fumaric acid contents were unaffected, regardless of the freezing conditions. Conclusion: The optimal freezing method for welsh onions with the least quality changes was determined to be immersed liquid freezing, following by preservation up to 7 months by freeze-storing.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.594-599
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• 1988

Methods by which liquid egg could be stored in liquid state at frozen storage temperature$(-15^{\circ}C)$ with selected cryoprotectants and enzyme treatment were investiated, and quality changes in samples during storage were examined. The concentration of cryoprotectants (45% fructose and 55% glucose) to be added to egg yolk and whole egg to store them at $-15^{\circ}C$ in unfrozen state were 45.2% and 70.3%, respectively. Changes in consistency, precipitation of protein and microstructure of egg samples during storage indicated that adding cryoprotectants to liquid egg could effectively inhibit development of gelation during storage at $-15^{\circ}C$. Treating liquid egg with 0.15% papain could inhibit gelation during storage to some extent.

• Journal of Animal Reproduction and Biotechnology
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• v.37 no.2
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• pp.106-112
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• 2022

Cryopreservation of porcine ovarian tissue by vitrification method is a promising approach to preserve genetic materials for future use. However, information is not enough and technology still remains in a challenge stage in pig. Therefore, the objective of present study was to determine possibility of vitrification method to cryopreserve porcine ovarian tissue and to confirm an occurrence of cryoinjuries. Briefly, cryoinjuries and apoptosis patterns in vitrified-warmed ovarian tissue were examined by histological evaluation and TUNEL assay respectively. In results, a damaged morphology of oocytes was detected among groups and the rate was significantly (p < 0.05) lower in vitrification group (25.8%) than freezing control group (67.7%), while fresh control group (6.6%) showed significantly (p < 0.05) lower than both groups. In addition, cryoinjury that form a wave pattern of tissues around follicles was found in the frozen control group, but not in the fresh control group as well as in the vitrification group. Apoptotic cells in follicle was observed only in freezing control group while no apoptotic cell was found in both fresh control and vitrification. Similarly, apoptotic patterns of tissues not in follicle were comparable between fresh control and vitrification groups while freezing control group showed increased tendency. Conclusively, it was confirmed that vitrification method has a prevention effect against cryoinjury and this method could be an alternative approach for cryopreservation of genetic material in pigs. Further study is needed to examine the viability of oocytes derived from vitrified-warmed ovarian tissue.

• 한국전자현미경학회:학술대회논문집
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• 2005.05a
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• pp.47-48
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• 2005