• Korean Journal of Microbiology
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• v.23 no.1
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• pp.69-76
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• 1985

This study was carried out to observe the formation of superoxide radicals and the changes in the activities of superoxide dismutase (EC.1.15.1.1.) from the various organs of a rat which was blocked tricarboxylic acid cycle. In order to block the tricarboxylic acid cycle, the beta-fluoroethylacetate was injected into peritoneal cavity of rat and removed the various tissues from the rat at internals of an hour. By tissue extracts being prepared by the method of Weigiger and Fridovich the activities of superoxide dismutase, aconitase, and contents of bliid glucose, citrates, and wuperoxide radicals were determined. The experimental results are summarized as follows: Accumulation of citrates if increased within three hours after treatment in the all tested tissues, especially, in the geart and spleen they are higher than one of other tissues as 12 and 20 times of control. The activities of aconitase are ingibited to 30-35% on an hour after beta-fluoroethylacetate treatment comparing with that of control rat. The content of blood glucose is increased to 1.6 fold of normal value after 5 hours of treatment. In all tested tissues, superoxide radicals are formed in the heart as 0.26 micromoles per gram tissue between one and three hours after treatment. The activities of total superoxide dismutase are increased between one and three hours after treatment in the all tested tissues and one of these enzymes in heart is highest. The activities of superoxide dismutase containing Mn are also increased with an increase of total superoxide dismutase activities.

• Korean Journal of Microbiology
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• v.51 no.4
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• pp.419-426
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• 2015

The aims of this study were to isolate spore-forming Bacillus strains that exhibit high digestibility and anti-pathogenic bacteria toward feed for calves. Total 136 spore-forming strains were isolated from finished feeds and their ingredients. Among them, 93 strains were identified as Bacillus species when analyzed by 16S rRNA sequencing. For industrial use, three strains named as Bacillus licheniformis SHS14, B. subtilis LCB7, B. amyloliquefaciens LCB10 were selected after evaluating the industrial standards that are related with heat and acid resistance, enzyme activities, and anti-pathogenic activities against Samonella dublin ATCC15480 and E. coli K99. After each culture, 3 selected strains were mixed together at 1:1:1 (v/v/v) ratio and then prepared as the mixed starter culture for feeding. The changes in microbial community were analyzed via 16S rRNA metagenomics. The initial community ratio among three strains was maintained even after manufacturing into final products. Also, in vitro, enzymatic and anti-pathogenic activities were almost same as those when cultured in single culture, and results of anti-pathogenic activities conducted with calves showed 90% activities against lincomycin, which would be indicative of a promising feed starter.

• Korean Journal of Agricultural Science
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• v.5 no.2
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• pp.87-92
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• 1978

Extensive studies on the commercial fermented milks, which had been distributed over four months from July to October in 1978, were carried out for their microbial characterization including an investigation on the variations of bacterial populations under various storage conditions. 1. Total number of viable cells in the products were in between $5{\times}10^7$ cells/ml and $73{\times}10^7$ cells/ml, and $62{\times}10^7$ cells/ml, however no coliform bacteria were detected in the products. 2. Acidities of the products were not very high but fit in the standard as appeared to be in between 0.4869% and 0.6689%. 3. The acidities of the products showed little changes when stored at $5^{\circ}C$, but rises in 22.55% at $20^{\circ}C$ and in 117.66% at $30^{\circ}C$. 4. Total viable counts weren't varied much upto 96 hours when stored at $5^{\circ}C$, but increased during first 24 hours then decreased gradually at the higher temperatures. 5. Viable counts of lactic acid bacteria were decreased markedly with ascending the storage temperature, showing minimal variations when stored at $5^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.10
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• pp.1301-1306
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• 2008

The physiological and microbiological characteristics of various mul-kimchis prepared with omija (Schiznadra chinensis) water extract (1, 2, 3 v/w%) (omija mul-kimchi ) or water (control) were investigated during fermentation for 21 days at $10^{\circ}C$. The pH of omija mul-kimchi was lower than that of control and lowered with increasing the concentration of omija between 1% and 3%. The pH did not change significantly during fermentation in omija mul-kimchi compared with control. The changes in titratable acidity were similar in pH. The change of total microbs and lactic bacteria during fermentation was similar in various mul-kimchis and the viable cell numbers in omija mul-kimchi were lower than in control. The viable cell of mul-kimchi decreased with increasing the concentration of omija water extract. The texture of various mul-kimchi such as hardness, cohesiveness, chewiness and springiness, was decreased but the texture of 1% omija mul-kimchi was maintained significantly higher than that of control during fermentation. The DPPH radical and nitrite scavenging activity of omija mul-kimchi were higher than those of control and the activities increased with increasing concentrations of omija water extract. The sensory quality of 1% omija mul-kimchi showed the highest value in taste and overall acceptability among the tested mul-kimchis.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.779-785
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• 1996

Sansung takju, the Korean traditional liquor at a local area of Sansung in Pusan, has been widely drunken due to its tradition in this area. The studies on microorganisms of kokja, fermentation process and shelf-life of takju were carried out. The most abundant microorganism identified from a commercial Sansung kokja was Aspergillus, Mucor, Rhizopus and Penicillium were also identified. In case of a home-made Sansung kokja, Mucor was the most abundant one. Aspergillus, Rhizopus and Absidia were also identified in it. Saccharomyces, Micrococcus and Bacillus were identified in both kokja's but acid production bacteria were not found. Ethanol fermentation was carried out at $25^{\circ}C$ and $30^{\circ}C$ using each kokja. The rate of ethanol production was faster at $30^{\circ}C$ than at $25^{\circ}C$, while higher viable yeast count and final ethanol content were obtained at $25^{\circ}C$ than at $30^{\circ}C$. The ethanol contents of the mashes using a commercial Sansung kokja and a home-made Sansung kokja after 14 days at $25^{\circ}C$ were 11.0% and 12.4%, respectively. The shelf-life of takju was affected more by ethanol content in the product than by storage temperature. The product stored at $-15^{\circ}C$ did not change significantly in acidity but tasted watery due to thawing. In case of Sansung takju containing 6%ethanol, level of acidity increased and pellicle was formed on the surface of the product during storage at $30^{\circ}C$. In case of Sansung takju containing 9% or 12% ethanol, no significant changes in acidity and appearance were observed for 14 days at $30^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1029-1034
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• 1999

To enhance the cleaning and sterilization effect of cooled electrolyzed acid water on lettuce, several kinds of polysorbates were used at various concentrations in immersion washing process. In case of the treatment containing polysorbate 20, coliform count of lettuce was reduced to about 1/40 level of that in non-treated lettuce. The treatment containing polysorbate 60 did not show a significant sterilization effect. Otherwise, the total and coliform counts of lettuce during immersion in electrolyzed acid water containing 1 ppm of polysorbate 80 was reduced to about 1/300 and 1/1,700 level of those in non-treated one. And, the changes of ORP(oxidation-reduction potential), pH and color value of lettuce in electrolyzed acid water containing 1 ppm of polysorbate 80 were not quite different during 60 min. immersion, but HCIO content decreased from 10.28 ppm to 8.51 ppm after 20 min. immersion. Also, total and coliform count of lettuce immersed in electrolyzed acid water containing 1 ppm of polysorbate 80 was lower to about 1/1,800 after 20 min. and 1/5,550 after 30 min, compared with non-treated lettuce.

• Food Science of Animal Resources
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• v.25 no.4
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• pp.403-408
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• 2005

The objective of this study was to investigate the effects of supplemental levels of Bamboo vinegar (BV) on meat quality characteristics of Hanwoo. A total of 15 cows $(400.0\pm15.0\;kg)$ was fed with a commercial diet (control) or $3\%$ bamboo vinegar supplemented diets $(3\%\;BV),\;6\%$ BV for four months. Then, cows were slaughtered and M. longissimus dorsi (LD) was collected from each treatment group During storage at $4^{\circ}C$ for 21day, physico-chemical, microbiological and sensory characteristics were determined It increased (p<0.05) in at 3 and 9 days of the refrigeration storage. Hunter a value decreased (p<0.05) in the meat fed with $3\%\;and\;6\%$ BV at 1, 3 and 9 days. Hunter b value increased (p<0.05) in $3\%\;and\;6\%$ BV at 1 and 3 days. TBA and total bacterial count were significantly (p<0.05) low in $3\%\;and\;6\%$ BV at 1 and 3 days. Supplementation of $3\%\;or\;6\%$ BV showed a significant (p<0.05) decrease in cooking loss at 9 and 15 days. $3\%\;and\;6\%$ BV showed a significant (p<0.05) decrease in shear force at 1, 3 and 9 days; it tended to decrease throughout the whole storage period The treatments $3\%\;and\;6\%$ BV scored high in area of taste; taste increased significantly (p<0.05) at 1 and 3 days.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.377-381
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• 2007

The aim of this study was to evaluate the microbial safety and quality changes of Korean sliced pork jerky, and to investigate these properties over 90 days and 28 days of storage at room temperature $(25^{\circ}C)$ and elevated temperature $(35^{\circ}C)$. Based on the microbial counts of pork jerky, mesophilic bacteria were detected at 2.50 log CFU/g at day 0. The mesophilic bacterial count did not change significantly for all samples, and coliform bacteria and Bacillus cereus were not detected in any samples during storage at either $25^{\circ}C\;or\;35^{\circ}C$. The following physicochemical qualities were also investigated: TBA value, Aw, and pH. In the case of $25^{\circ}C$ storage, the Aw of Korean sliced pork jerky was 0.72 at day 0, and was reduced to 0.58 after 90 days of storage. The TBA value increased as the storage time increased, and was 0.52 after 90 days of storage. The pH of all samples did not change significantly. In the case of $35^{\circ}C$ storage, the TBA, Aw, and pH values were not significantly different from those obtained during $25^{\circ}C$ storage. In addition, the sensory properties of all samples were not significantly different between storage at the two temperatures. In conclusion, these results suggest Korean sliced pork jerky could be used to study the development of commercial pork jerky.

• Korean Journal of Microbiology
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• v.46 no.4
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• pp.383-388
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• 2010

Alkaline protease-overproducing strains of Vibrio metschnikovii were developed by using the molecular evolution from the classical mutants V. metschnikovii L12-23, N4-8, and KS1. Each vapK (Vibrio alkaline protease K) was obtained from the genomic DNAs of mutants by PCR to carry out the DNA shuffling. The modified vapK-1 obtained by DNA shuffling was used again as a template for the error-prone PCR to make the vapK-2. Both genes were cloned in the plasmid pKF3 to construct the recombinant plasmids which have one or two copies of the modified genes. The recombinant plasmids were back-transformed to V. metschnikovii KS1 to construct recombinant V. metschnikovii that expresses the alkaline protease. About 3.9-fold more protease activity was measured in the strain which has the plasmid containing two copies of vapK-2 when compared to strain KS1. When compared to wild type V. metschnikovii RH530, 43-fold more activity was achieved. Comparison of amino acids among vapK, vapK-1, and vapK-2 revealed that the active sites was highly conserved and not changed. However, many amino acids except the active sites were changed. These results suggested that the changes in amino acids might play an important role in the increase of protease activity by allowing the easy access of substrate to active sites of the protease. The fermentation of alkaline protease from the V. metschnikovii KS1 harboring the plasmid that contains two copies of vapK-1 showed the possibility of this strain to be used as industrial producer.

• Korean Journal of Microbiology
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• v.50 no.1
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• pp.8-14
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• 2014

The objective of this work is to investigate and compare several functional properties of lactic acid bacteria (LAB), Lactobacillus casei SK-7 isolated from home-made yogurt and Lactobacillus bulgaricus YK-11 from commercial yogurt. Initially, physiological and biochemical properties of SK-7 and YK-11 were characterized. Phylogenetic analysis using 16S rRNA sequencing were performed to identify the strains, and the strain could be assigned to Lactobacillus casei and Lactobacillus bulgaricus, designated as L. casei SK-7 and L. bulgaricus YK-11. Phylogenetic tree of SK-7 and YK-11 was plotted based on 16S rRNA sequence comparisons. Production of lactic acid and organic acid, and pH changes in the cultures of SK-7 and YK-11 were monitored during 72 h. During the incubation period, several functional properties of L. casei SK-7 and L. bulgaricus YK-11 were examined. L. casei SK-7 and L. bulgaricus YK-11 cultures eliminated 93.9% and 88.2% of nitrite, respectively. Antioxidant activity of cultural supernatants of SK-7 and YK-11 were 62.6%, 54.9%, and activity of ${\beta}$-galactosidase were 14.9 units/mg and 13.1 units/mg, respectively. The antimicrobial activities were examined with 20-fold concentrated culture supernatants from the cultures of SK-7 and YK-11. The activities of SK-7 supernatants were clearly observed against all microorganisms in this work, whereas no activities were observed in YK-11 supernatants. Although it might be conducted additional functional research, functional properties of LAB isolated from home-made yogurt have been shown to be better than those of commercial yogurt in this work.