• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1095-1101
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• 2001

Spinach was minimally processed into the unseasoned side dish to be used for Korean food service industry, using the techniques of cook-chill and sous vide. Spinach was blanched at 10$0^{\circ}C$ for 6 minutes, vacuum-packaged in the unit of 500 g by plastic film of low gas permeability, pasteurized at 9$0^{\circ}C$ and then cooled rapidly at 3$^{\circ}C$. The chilled products were then stored at 3 and 1$0^{\circ}C$ with measurement in their quality. Six log cycle (6D) inactivation of Listeria monocytogenes and 13 log (13D) thermal destruction of Streptococcus faecalis were compared as two pasteurization conditions, which corresponded to heating for 22.8 and 30.0 minutes at 9$0^{\circ}C$, respectively. Milder heat processing based on 6D process of L monocytogenes gave better quality of color, texture, ascorbic acid and chlorophyll than the conditions of 13D process of S. faecalis. Any microbial growth in total aerobic, psychrophilic and anaerobic bacteria was not observed until 8 days at 1$0^{\circ}C$ and 14 days at 3$^{\circ}C$, which might be regarded as strict guidelines of shelf life. Storage times based on the changes in physical and chemical quality were longer than those based on strict microbial quality in case of the products pasteurized by 6D process of L. monocytogenes. The seasoned vegetables prepared from sous vide processed spinach were found to be inferior in sensory quality to those from freshly blanched one.

• Applied Biological Chemistry
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• v.28 no.4
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• pp.252-260
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• 1985

The changes of the qualities and the components of 5 different Takju (Korean wine) in various stroage temperatures were evaluated. Commercial Takju didn't change in acidity and alcoholic degree at $5{\sim}10^{\circ}C$ for 36 hours. But at $30{\sim}35^{\circ}C$ the alcohollic degree has inversed to $5.0{\sim}7.0$. As time went by, pH nearly went down to pH 3.7 and went up back over 4.0. Amino acidity was risen continuously during the stroage terms and the change of reducing sugar was irregular. The number of vegetable cell of yeast in commercial Takju at $30{\sim}35^{\circ}C$ after 18 hours was $2.4{\times}10^8$, at $5{\sim}10^{\circ}C$ after 36 hours $2.4{\times}10^8$, and each of them was reduced below $1{\times}10^8$ after exceeding the limit of shelf-life. Number of general bacteria was increased suddenly in a high temperature at the first and it was decreased afterwards, but the tendency of increase and decrease was slow in a low temperature. It was possible to keep the quality for 5 days at $5{\sim}10^{\circ}C$ in case of commercial Takju and the shelf-life of pasteurized Takju was extended over 7 days.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.322-325
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• 1990

During transportation and preservation of Takju, alcohol fermentation has continued to produce $C0_2$ from residual sugar and frequently spoiled owing to bacterial contaminants wich produce organic acids. The authors could preserve Takju for more than 50 days at room temperature by pasteurization without any changes of quality. For the optimal condition of pasteurization, fresh Takju was heated at various temperatures and times. D-Value of the Saccharomyces sp. which isolated from Takju collected at seoul area was 19 see at $55^{\circ}C$. Non-spore forming bacterial contaminants, most of which known to cause acid-spoilage, were decreased when heated at $55^{\circ}C$ for 5 min. The optimal pasteurization condition of Takju was at $55^{\circ}C$ for 10 min. Spore forming bacterial contaminants, considered to be EuciiLw sp., were not sterilized after pasteurized at the optimal condition. However, the spore-forming bacteria could not increase any more and also not cause increment of acidity during preservation even at room temperature for 50 days. Reducing sugar was increased during storage of Takju after pasteurization. This suggests that the residual glucoamylase in Takju is still active after pasteurizsation and keep sweet taste.

• 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.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.198-204
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• 2011

This study was carried out to investigate occurence of microbiales density and characteristics of xylanase produced by those in Janggyeong Panjeon. Cladosporium cladosporioides H1, Penicillium citreonigrum H3, Penicillilum toxicarium H4, Aspergillus versicolor H6, Acremonium alternarium H7 isolated from Janggyeong Panjeon produced xylanase, which had different production rates and specialized activities in an acidic condition. Cladosporium cladosporioides H1, Aspergillus versicolor H6, and Acremonium alternatum H7 produced xylanase at a faster rate than other fungi. A xylanase of Cladosporium cladosporioides H1 and Penicillilum toxicarium H4 showed a high thermostability in an acidic condition. As results, this study may lead to the development of a strategy for preservation of organic cultural heritages.

• Food Science of Animal Resources
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• v.22 no.3
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• pp.247-251
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• 2002

This study was carried out to investigate the keeping quality of market milks collected from several dairy processing companies. Microbiological, chemical, and sensory properties of Intra-high temperature(UHT) treated milks stored at 5, 10, 15t were evaluated during the storage of 154days. No significant difference during the storage was shown in bacterial counts, pH and titratable acidity. Standard plate count(SPC) was remained less than 20,000 cfu/ml after 15 day storage at 5, 10, 15$^{\circ}C$. Also, Psychrotrophic bacterial count and Coliform count were not detected or detected at low level. The pH ranged from 6.55 to 6.83 and the titratable acidity ranged from 0.13% to 0.16%. In sensory evaluation, UHT milks showed normal flavor until 10days, but thereafter off-flavor was slightly developed. Consequently, UHT milks remained in good quality when stored at 5$^{\circ}C$,10$^{\circ}C$t until 15days except sensory properties. According to this experiment, the shelf-life of UHT milk can be extended to 10 days, even though maintaining the storage temperature strictly below 10 t in milk market is not easy.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1341-1349
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• 2000

The addition of 5% NaCI to standard plate count (SPC) and bromcresol purple (BCP) agar showed the highest viable cell counts for Jeot-kal samples. The use of 15% glycerol as cryoprotectant showed the highest microbial survival rate at both temperatures, $-20^{\circ}C$ and $-170^{\circ}C$, and on both colony count media, SPC and BCP. During the aging, the pH of Bajirak Jogae-Jeot (fermented clam) decreased from 6.8 to 5.0. Crude protein content was 10% for Bajirak Jogae-Jeot and $6{\sim}7%$ for Myeolchi-Jeot (fermented anchovy). Microbial population of Bajirak Jogae-Jeot was $10^9\;CFU/g$ after 4 weeks of aging, but was only $10^{3-5}\;CFU/g$ in the case of Myeolchi-Jeot. The proportion of Gram positive and catalase negative bacteria in Bajirak Jogae-Jeot increased drastically during the 4 weeks of aging, which showed typical lactic bacterial fermentation. After 2 years' storage of Jeot-kal in liquid nitrogen tank, the cell counts of total aerobic or lactic bacteria were decreased, resulting in about 10% survival rate. Microbial floral change of Jeot-kal was also investigated. In the case of Bajirak Jogae-jeot, the ratio of rod to cocci and that of Gram negative to positive increased after liquid nitrogen storage. But, rod to cocci ratio of Myeolchi-jeot decreased after liquid nitrogen storage. The ratio of yeasts decreased in both cases after storage.

• Korean Journal of Plant Taxonomy
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• v.36 no.1
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• pp.61-89
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• 2006

Algific talus slopes are local cold micro-environmental habitats where cool air escapes through vents and fissures of talus layer, and ice forms in summer. To access the phytogeographical significance and to develop the conservation strategy on vegetation of the algific talus, plant species composition on seven algific talus in South Korea was investigated. As a results, phytogeographically significant northern elements such as Cystopteris fragilis (L.) Bernh., Diplazium sibiricum (Turcz. ex Kunze) Sa.Kurata, Polypodium virginianum L., Vaccinium vitis-idaea L. and Hackelia deflexa (Wahlenb.) Opiz were distributed in these algific talus slopes (below $N37^{\circ}43^{\prime}$). In addition, subalpine species such as Woodsia subcordata Turcz, Rosa suavis willd., Clematis fusca var. coreana ($H.L{\acute{e}}v.$ & Vaniot) Nakai, Calamagrostis langsdorfii (Link) Trin. and Carex vaginata var. petersii (C.A.Mey.) Akiyama were also distributed as typical relictual species of these algific talus (less than alt. 400m). The algific talus slopes in Korean peninsular can be regarded as the insular refugia that northern plant species advanced southward during the latest glacial age have been isolated and adapted in some local microhabitats. Because the algific talus slopes as paleorefugia are very important in terms of phytogeography as well as meteorology ans geology, developments of strategies for in situ and ex situ conservation on these small isolated and threatened populations associated with the algific talus urgently needed.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.240-251
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• 2019

This study examined the manufacturing technology used for the flat iron axes excavated from Ulsan Hadae. Their microstructures were analyzed using metallurgical methods. In addition, a variety of manufacturing technologies were examined and compared using existing research materials on flat iron axes. As a result of analyzing ten flat iron axes, which were excavated in the order that they were laid out in a row in one of the wooden coffin tombs at Ulsan Hadae, Tomb No. 44, it was possible to classify the flat iron axe manufacturing technology and system into three types: 'pure iron - shape processing', 'pure iron - shape processing - carburizing', and 'pure iron - shape processing - carburizing - decarburizing.' All of the flat iron axes were produced by forging, and most of them were made by beating the pure iron into their shapes. In particular, a number of the flat iron axes were reinforced through a carburizing process after shaping the iron. This appears as steel products forming the basis of the steel industry at the time were commonly used as an intermediary material or currency. On the other hand, it was commonly found in all samples that the hardening was not performed after shaping or carburizing. Since the microstructure of the flat iron axes made of pure iron contained a large number of impure inclusions and the result of analyzing the components of the non-metal inclusions showed characteristics of slag which contains a mixture of glass phase and wustite, it is possible that low-temperature reduction was used in the refining process.

• Journal of Dairy Science and Biotechnology
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• v.29 no.2
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• pp.25-35
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• 2011

The objectives of this study were to evaluate the sensory characteristic quality of commercial milk brands selling in the market under the preservation at the temperature of $7^{\circ}C$ and $10^{\circ}C$ stored during the period of shelf-life. Quantitative descriptive analysis after developing of descriptive terms and cluster characterization by PCA analysis over a total of 128 LTLT, HTST, UHT and UHT-ESL milks, were conducted by 8 trained panelists. A total of fourteen attributes; three aroma attributes (grassy, milky, cultured milk aroma) and seven flavor/taste attributes (sweet, salty, sour, milk, cooked, cheesy, paper board) and one aftertaste attributes (rancid flavor) and one texture attributes (viscous), were developed as descriptive terms. Significant differences (P<0.01) in the sensory attributes; sweet, milky, cheesy etc. in UHT milk and sour, cheesy, paper board, rancid etc. in UHT-ESL milk were also found between the two different temperatures within the shelf life, but both type of pasteurized milk samples (LTLT and HTST) showed significant differences (P<0.01) in the attributes, such as cultured milk aroma, salty, sour, cheesy, rancid in LTLT milk and grassy, milky, salty in HTST milk and difference (P<0.05) in cultured milk aroma for HTST milk. Therefore, from the viewpoint of not only hygienic quality but also sensory characteristics, it is required for the better acceptance of milk consumers to amendment on the regulation in relation to the preservation standard of pasteurized milk as well as UHT milk to lower than $7^{\circ}C$.