• KSBB Journal
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• v.29 no.4
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• pp.285-296
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• 2014

Although the problems of the algal blooms have been world-widely observed in freshwater, estuary, and marine throughout the year, it is not yet certain what are the basic causes of such blooms. Consequently, it is very difficult to predict when and where algal blooms occur. The constituents of the Asian dust are in a good agreement with the elements required for the algal growth, which suggests some possible relationship between the algal blooms and the Asian dust. There have been frequently algal blooms in drinking water from rivers or lakes. However, there is no any algal blooms in upwelling waters where the Asian dust cannot penetrate into the soil due to its relatively weak settling velocity (size of particles, $4.5{\pm}1.5{\mu}m$), which implies the possible close relationship of the Asian dust with algal blooms. The present initiative study is thus intended firstly in Korea to illustrate such a relationship by reviewing typical previous studies along with 12 years of weekly iron profiles (2001~2012) and two slant culture experiments with the dissolved Asian dust. The result showed bacterial suspected colonies in the slant culture experiment that are qualitatively in a good agreement with the recent Japanese studies. Since the diatoms require cheap energy (8%) compared to other phytoplankton (100%) to synthesize their cell walls by silicate, the present results can be used to predict algal blooms by diatoms if the concentrations of iron and silicate are available during spring and fall. It can be postulated that the algal blooms occur only if the environmental factors such as light, nutrients, calm water surface layer, temperature, and pH are simultaneously satisfied with the requirements of the micronutrients of mineral ions supplied by the Asian dust as enzymatic cofactors for the rapid bio-synthesis of the macromolecules during algal blooms. Simple eco-friendly methods to regulate the algal blooms are suggested for the initial stage of blooming with limited area: 1) to cover up the water surface with black curtain and inhibit photosynthesis during the day time, 2) to blow air (20.9%) or pure oxygen into the bottom of the water and inhibit rubisco for carbon uptake and nitrate reductase for nitrogen uptake activities in algal growth during the night, 3) to eliminate the resting spores or cysts by suction of bottom sediments as deep as 5 cm to prevent the next year germinations.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.50-55
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• 2010

This study was conducted to investigate the shelf-life and quality of breads made with 0.5, 1 and 2% of Myagropsis myagroides fermented ethanol extracts (MOE). The total microbial count in breads made with 2% MOE decreased to about 1.6 log cycles as compared to that of breads not containing MOE. The protection index measured by rancimat increased with an increase in the quantity of MOE in the breads. During the storage period, the pH value was not different between breads containing MOE and breads not containing MOE. The lightness and redness of the breads decreased with an increase in the quantity of MOE, while the yellowness increased. In the sensory evaluation, the breads containing 0.5% MOE were more preferred than the breads not containing MOE. These results suggest that the addition of 0.5% MOE to breads has a good effect on improving the shelf-life and overall quality.

• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.37-44
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• 2020

This study investigated the probability of foodborne illness caused by raw oyster consumption contaminated with high risk Vibrio species such as V. vulnificus and V. cholerae. Eighty-eight raw oyster samples were collected from the south coast, west coast and Seoul areas, and examined for the prevalence of high risk Vibrio species. The growth patterns of V. vulnificus and V. cholerae in raw oysters were evaluated, and consumption frequency and amounts for raw oyster were investigated from a Korean National Health and Nutrition Examination Survey. With the collected data, a risk assessment simulation was conducted to estimate the probability of foodborne illness caused by intake of raw oysters, using @RISK. Of 88 raw oysters, there were no V. vulnificus- or V. cholerae-positive samples. Thus, initial contamination levels of Vibrio species in raw oysters were estimated by the statistical methods developed by Vose and Sanaa, and the estimated value for the both Vibrio spp. was -3.6 Log CFU/g. In raw oyster, cell counts of V. vulnificus and V. cholerae remained unchanged. The incidence of raw oyster consumers was 0.35%, and the appropriate probabilistic distribution for the consumption amounts was the exponential distribution. A risk assessment simulation model was developed with the collected data, and the probability of the foodborne illness caused by the consumption of raw oyster was 9.08×10^-15 for V. vulnificus and 8.16×10^-13 for V. cholerae. Consumption frequency was the first factor, influencing the probability of foodborne illness.

• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.51-59
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• 2020

This study evalutated the risk of foodborne illness from Vibrio spp. (Vibrio vulnificus and Vibrio cholerae) through sea squirt consumption. The prevalence of V. vulnificus and V. cholerae in sea squirt was evaluated, and the predictive models to describe the kinetic behavior of the Vibrio in sea squirt were developed. Distribution temperatures and times were collected, and they were fitted to probabilistic distributions to determine the appropriate distributions. The raw data from the Korea National Health and Nutrition Examination Survey 2016 were used to estimate the consumption rates and amount of sea squirt. In the hazard characterization, the Beta-Poisson model for V. vulnificus and V. cholerae infection was used. With the collected data, a simulation model was prepared and it was run with @RISK to estimate probabilities of foodborne illness by pathogenic Vibrio spp. through sea squirt consumption. Among 101 sea squirt samples, there were no V. vulnificus positive samples, but V. cholerae was detected in one sample. The developed predictive models described the fates of Vibrio spp. in sea squirt during distribution and storage, appropriately shown as 0.815-0.907 of R² and 0.28 of RMSE. The consumption rate of sea squirt was 0.26%, and the daily consumption amount was 68.84 g per person. The Beta-Poisson model [P=1-(1+Dose/β)^-α] was selected as a dose-response model. With these data, a simulation model was developed, and the risks of V. vulnificus and V. cholerae foodborne illness from sea squirt consumption were 2.66×10^-15, and 1.02×10^-12, respectively. These results suggest that the risk of pathogenic Vibrio spp. in sea squirt could be considered low in Korea.

• Korean Journal of Food Science and Technology
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• v.41 no.1
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• pp.50-56
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• 2009

This study was carried out to determine the optimum extraction conditions for Ishige okamurai by comparing the yields, total phenolic compound content (TPC), and antioxidant properties of its 95%, 70%, 50% fermented ethyl alcohol and water extracts. Additionally, the effects of heat and pH treatments on the antioxidant properties of the extracts were evaluated by their TPC and 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging capabilities. The yields of the extracts were greatest in the order of water > 50% > 70% > 95% fermented ethyl alcohol, and the TPC of the 70% (26.18%) and 50% fermented ethyl alcohol (27.56%) extracts were higher than those of the others. However, in terms of DPPH radical scavenging and ferrous-reducing power, the 70% fermented ethyl alcohol extract of Ishige okamurai showed the highest antioxidant effects. Additionally, in the results for the heat and pH treatments, the antioxidant properties of the 70% fermented ethyl alcohol extract were not influenced by the treatment conditions except at pH 10.

• Journal of Life Science
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• v.22 no.10
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• pp.1295-1306
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• 2012

A microorganism producing carboxymethylcellulase (CMCase) was isolated from seawater and identified as Bacillus atrophaeus. This species was designated as B. atrophaeus LBH-18 based on its evolutionary distance and the phylogenetic tree resulting from 16S rDNA sequencing and the neighbor-joining method. The optimal conditions for rice bran (68.1 g/l), peptone (9.1 g/l), and initial pH (7.0) of the medium for cell growth was determined by Design Expert Software based on the response surface method; conditions for production of CMCase were 55.2 g/l, 6.6 g/l, and 7.1, respectively. The optimal temperature for cell growth and the production of CMCase by B. atrophaeus LBH-18 was $30^{\circ}C$. The optimal conditions of agitation speed and aeration rate for cell growth in a 7-l bioreactor were 324 rpm and 0.9 vvm, respectively, whereas those for production of CMCase were 343 rpm and 0.6 vvm, respectively. The optimal inner pressure for cell growth and production of CMCase in a 100-l bioreactor was 0.06 MPa. Maximal production of CMCase under optimal conditions in a 100-l bioreactor was 127.5 U/ml, which was 1.32 times higher than that without an inner pressure. In this study, rice bran was developed as a carbon source for industrial scale production of CMCase by B. atrophaeus LBH-18. Reduced time for the production of CMCase from 7 to 10 days to 3 days by using a bacterial strain with submerged fermentation also resulted in increased productivity of CMCase and a decrease in its production cost.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.962-968
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• 2002

Effects of gamma-irradiation of 1 to 10 kGy on the microbial growth, contents of amino acids, fatty acids, and free sugars, and changes in acid values in soybean powder were studied. Irradiation doses at $3{\sim}5\;kGy$ inhibited the mold growth completely in two kinds of imported soybean powders. Contents of sulfur-containing amino acids, such as cysteine, in both soybean powders decreased with irradiation, whereas no significant changes in free amino acid and fatty acid contents of both soybean powders were observed. Free sugar contents of stachyose and sucrose in Chinese soybean powder decreased with increasing irradiation dose level, whereas, those of other sugars remained unchanged. Results of this study confirm that $3{\sim}5\;kGy$ irradiation can be safely applied to apply to soybean powder without causing significant quality deteriorations microbiologically and chemically.

• Food Science and Preservation
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• v.19 no.6
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• pp.909-918
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• 2012

The phenolic compounds which were extracted with 70% ethanol from Ulmus pumila for 12 hr were the highest as $17.9{\pm}1.0\;mg/g$. DPPH scavenging activity of 70% ethanol extracts was also the highest as $89.5{\pm}1.9%$ and it was confirmed to be high as 80% over in both of water and 70% ethanol extracts containing $50{\mu}g/mL$ over phenolic concentration. ABTS radical cation decolorization activities of water and 70% ethanol extracts were higher as $96.8{\pm}2.9%$, antioxidant protection factor (PF) was 2.0 PF in 70% ethanol and showed higher activities in both of water and 70% ethanol extracts containing $200{\mu}g/mL$ phenolic concentration as 2.5 PF than BHA. TBARs of 70% ethanol extracts was $86.5{\pm}4.6%$, it showed high anti-oxidative activity in $50{\sim}200{\mu}g/mL$ phenolic concentrations of water and 70% ethanol extracts as 80% over. The angiotensin converting enzyme (ACE) inhibitory activity of Ulmus pumila extracts against hypertension was 77.4% and 90.6% in water and 70% ethanol extracts of $200{\mu}g/mL$ phenolic concentration. Xanthine oxidase inhibitory activity of Ulmus pumila extracts for anti-gout effect was not observed in water extracts, but it showed 30% inhibitory activity in 70% ethanol extracts, and 48.1% at $200{\mu}g/mL$ phenolics concentration.

• Journal of Life Science
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• v.29 no.4
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• pp.402-409
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• 2019

Korean red ginseng made from steaming and drying fresh ginseng has long been used as a traditional herbal medicine due to its effects on the immune, endocrine, and central nerve systems and its anti-inflammatory activity. In this study, we investigated the molecular mechanism responsible for the anti-inflammatory effects of a formulated Korean red ginseng extract (RGE) in response to lipoteichoic acid (LTA), a cell wall component of gram-positive bacteria. RGE inhibited LTA-induced nitric oxide (NO) secretion and inducible nitric oxide synthase (iNOS) expression in BV-2 microglial cells, without affecting cell viability. RGE also inhibited nuclear translocation of nuclear factor kappa B ($NF-{\kappa}B$) p65 and degradation of $I{\kappa}B-{\alpha}$. In addition, RGE increased the expression of heme oxygenase-1 (HO-1) in a dose-dependent manner, and the inhibitory effect of RGE on iNOS expression was abrogated by small interfering RNA-mediated knockdown of HO-1. Moreover, RGE induced nuclear translocation of nuclear factor E2-related factor 2 (Nrf2), a transcription factor that regulates HO-1 expression. Furthermore, the phosphoinositide-3-kinase (PI-3K) inhibitor and mitogen-activated protein kinase (MAPK) inhibitors suppressed RGE-mediated expression of HO-1, and RGE enhanced the phosphorylation of Akt, extracellular signal-regulated kinases (ERKs), p38, and c-JUN N-terminal kinases (JNKs). These results suggested that RGE suppressed the production of NO, a proinflammatory mediator, by inducing HO-1 expression via PI-3K/Akt- and MAPK-dependent signaling in LTA-stimulated microglia. The findings indicate that RGE could be used for the treatment of neuroinflammation induced by grampositive bacteria and that it may have therapeutic potential for various neuroinflammation-associated disorders.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.3
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• pp.100-117
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• 2022

This study examines the spatio-temporal characteristics of the macrobenthic community in the coastal areas of South Korea for the past six years(2015-2020). The relationship between the number of individuals of macrobenthic species and the benthic environments were investigated using data collected at a total of 154 stations located in the West (70), the South (61), and the East Seas (23), except for the Jeju Sea. We examined the benthic environmental characteristics such as water depth, sediment, grain size, ignition loss, and total organic carbon. A total of 1,614 macrobenthic species were found in the coastal area, with a mean density of 0.62 ind./m² by station. The mean density was relatively high in the spring and summer seasons (May to August) with more than 450 species. The most dominant species belong to Polychaetes and the top five of them accounted for more than 20% of the total number of populations. The top five species were Heteromastus filiformis, Scoletoma longifolia, Sigambra tentaculata, Sternaspis scutata, and Notomastus latericeus. Cluster analysis was performed on the top five dominant species. The stations were clustered into three groups with similar locations on the West, South, and East Sea. Cluster 1 and 3 represent Heteromastus filiformis (44% each), but cluster 2 represents Scoletoma longifolia (66%). Each cluster has different benthic environmental characteristics, especially in the sediment's sand (31.0%, 51.9%) and clay (15.9%, 9.7%) contents.