• Korean Journal of Ecology and Environment
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• v.56 no.1
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• pp.1-13
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• 2023

Targeting Microcystin (MC), which is most abundantly detected in the North-Han River water area, we analyzed the relationship between the MC biosynthesis gene (mcyA gene), cyanobacteria cell density, and MC concentration, derived an RNA-MC conversion formula, and derived the cyanobacteria. The concentration of MC present in cells was predicted. In the North-Han River waters, the mcyA gene was found mainly at downstream sites of the North-Han River after Muk-Hyeon Stream junction, and higher copy numbers were found on average than other sites. In the Uiam Lake waters upstream of the North-Han River, the mcyA gene copy number increased at the Kong-Ji Stream point, and after September, the mcyA gene copy number decreased throughout the North-Han River waters. The expression of the mcyA gene was concentrated in the short period of summer due to the spatio-temporal difference between upstream and downstream water bodies. The mcyA gene expression level was not only highly correlated with MC concentration, but also correlated with the cell density of Microcystis aeruginosa and Dolichospermum circinale, which are known to biosynthesize MC. Six conversion formulas derived based on the RNA-MC relationship showed statistical significance (p<0.05) and exhibited high correlation coefficients (r) of 0.9 or higher. The expression level of MC biosynthesis gene present in eRNA determines the synthesis of cyanotoxin substances in water, quickly quantifies gene activity, and can be fully utilized for early warning of MC development.

• Culinary science and hospitality research
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• v.21 no.6
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• pp.103-119
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• 2015

This study was carried out to evaluate the quality of characteristics of Takju, Yakju, and spirit made from Bunkuk(flour), Phellinus linteus and Ginger kuk. The sacharogenic power of Nuruks and pH, brix, acidity, cell numbers of yeast, and alcohol content of Deotsuls were analysed; flavors, organic acids, and sensory evaluation of Takju, Yakju, and spirit were employed in the analysis of this current study. Results showed that the saccharogenic power of Phellinus linteus kuk after fermentation of Nuruks showed the highest level, and Phellinus linteus kuk and Ginger kuk showed the same level after dry Nuruks. During fermentation of Deotsuls, pH and brix decreased with increased fermentation time, while acidity increased with increased fermentation time. Cell numbers of yeast were found to be at the highest level in Phellinus linteus kuk on the first day of fermentation, and it was the same result in the final stage(p<0.05). Alcohol content increased with an increase in fermentation time, and showed no significant difference between control and test in the final stage of fermentation. In terms of analysis of flavor components, acetone and n-amyl alcohol were not detected in Takju, Yakju, and spirit. n-butanol was detected at the highest value, followed by i-amyl alcohol. Fusel oil was detected at the highest level in spirit fermented by Bunkuk. In analysis of organic acids, lactic acid showed the highest content followed by acetic acid. Very small amounts of acetic acid were detected in the spirit and other organic acids were not detected. In sensory evaluation, Takju, Yakju, and spirit made from Phellinus linteus kuk showed the highest score. As a result of this study, Phellinus linteus kuk presented the most desirable Nuruk in order to make Takju, Yakju, and spirit.

• Applied Biological Chemistry
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• v.48 no.2
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• pp.132-139
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• 2005

The major obstacle in the popularization of Chungkookjang is the short shelf-life of $2{\sim}3$ months and some problems concerning storage including the growth of molds even in the products even within shelf-life. To solve these problems we conducted a research to improve its storage by using the vacuumed packaging and sanitary method through seed culture, innoculation and sterilization. For the optimization of storage time, temperature and sterilization temperature, we measured viable cell numbers of bacteria and fungi, amount of gas outbreak and contents of amino type nitrogen and monitored these experimental results by response surface methodology of SAS program, so that we could observe the quality changes of Chungkookjang during shelf-life. Especially fungi, which are the biggest troublemaker in Chungkookjang shelf-life, couldn't be detected from the generally and vacuum-packed samples; also, viable cell numbers were highly influenced by sterilization temperature and in vacuum-packed samples. In the case of vacuum-packed samples, amount of gas outbreak was highly influenced by sterilization temperature of its storage conditions and it was higher in generally packed samples as compared to vacuum-packed samples even at any storage conditions. The changes of pH in generally and vacuum-packed samples were highly influenced by the storage temperature. As the temperatures of storage and sterilization were higher and the storage time was longer, so the amount of gas outbreak was accordingly lower. These results showed that amino type nitrogen contents in generally and vacuum-packed samples were systematically influenced by the temperature, storage time and sterilization temperature. Also the result showed that the change of amino type nitrogen contents during storage was less in vacuum-packed samples than in general ones. Based on the above results, we can produce Chungkookjang products with extended shelf-life of as far as 6 months without any quality change using sanitary manufacturing method, vacuumed packaging condition, sterilization in $70^{\circ}C$ for 60 minutes and storage under $10^{\circ}C$ during shelf-life. According to this research, we have the possibility to greatly increase the goods value of Chungkookjang by developing the manufacture processing and packaging.

• Applied Biological Chemistry
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• v.50 no.3
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• pp.167-177
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• 2007

This study was carried out to develop natural vinegared kochujang. We first formulated vinegared kochujang containing pine needle (PN) and Artemisia princeps (AP) extracts. A dominant strain was isolated from the vinegared kochujang and identified as Bacillus amyloliquefaciens ER282 based on the 16S rDNA sequence. The plant extracts of PN and AP were also investigated for their antibacterial activity and showed enough good activities to use for vinegared kochujang as a natural preservative. Quality characteristics of vinegared kochujang were evaluated, based on total cell numbers, pH, acidity, sugar content, color and sensory evaluation during storage at $25^{\circ}C$ and $37^{\circ}C$, respectively, for 3 weeks. No significant differences were found in the pHs and acidities of vinegared kochujang added with the plant extracts of PN and AP during their storage compared to starting time; however, total cell numbers were gradually decreased during the storage at $25^{\circ}C$ and $37^{\circ}C$, as the storage period was increased. For sensory evaluation, overall preference continuously declined depending on storage period, but the addition of 3% extracts of PN could delay the quality loss of vinegared kochujang during storage at $25^{\circ}C$ and $37^{\circ}C$ for 3 weeks.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.4
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• pp.506-512
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• 2003

Peach wine was fermented at $25^{\circ}C$ for 2 weeks using Saccharomyces cerevisiae KCCM 12224, aged at 15$^{\circ}C$ for 14 weeks, and its physicochemical and microbiological changes were investigated. The viable bacterial cell numbers, 1.4$\times$10$^3$ CFU/mL at the beginning of fermentation, increased to 2.8$\times$10$^{6}$ CFU/mL after 2 weeks, but decreased to 7.0$\times$10$^3$ CFU/mL after 14 weeks. The viable yeast cell numbers were changed from 3.4$\times$10$^2$ CFU/mL to 2.4$\times$10$^{7}$ CFU/mL during fermentation, and decreased to 4.0$\times$10$^4$ CFU/mL after aging. Turbidity total sugar content, reducing sugar content, solid content and b value of peach wine decreased during fermentation but acidity, alcohol content, L and a value increased. Most physicochemical properties except alcohol content and reducing sugar content were not changed significantly during aging. When peach wine was filtered through 0.45 ${\mu}{\textrm}{m}$ nitrocellulose membrane followed by various ultrafiltration membranes with different molecular weight cut-off values, Biomax 100K membrane, with 79 liter/$m^2$/h (LMH) of initial flux, was suitable for ultrafiltration process of peach wine. These membrane filtration treatments resulted in complete removal of microorganisms and decrease in turbidity and alcohol content without changes in other chemical properties. The physicochemical properties of peach wine were not changed and any microorganisms were not found during the storage at 3$0^{\circ}C$ for 12 Weeks.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.57-67
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• 2011

Agaricus brasiliensis, one of edible mushroom belonging to Basidiomycota, has been used for curing gastric ulcer and stomach cancer of human beings and also known to have good inhibitory effects on sarcoma 180 and Ehrlich carcinoma of mice. Neutral saline soluble (0.9% NaCl), hot water soluble and methanol soluble substances (hereinafter referred to Fr. NaCl, Fr. HW and Fr. MeOH, respectively) were prepared from fruiting body of the mushroom. ${\beta}$-glucan and total protein contents were identify from fractions of edible mushrooms extract. The ${\beta}$-glucan and protein contents of all fractions of the mushrooms ranged from 21.54~32.31% and 0.16~9.34%, respectively. In vitro cytotoxicity tests, crude polysaccharides were not cytotoxic against cancer cell lines such as Sarcoma 180, HT-29, NIH3T3 and RAW 264.7 at the concentration of 10~2000 ${\mu}g/ml$. Intraperitoneal injection with crude polysaccharides exhibited life prolongation effect of 18.8~50.6% in mice previously inoculated with Sarcoma 180. Fr. HW increased the numbers of spleen cell by 1.2 fold at the concentration of 200 ${\mu}g/ml$ compared with control. Fr. MeOH and Na improved the immuno-potentiating activity of B lymphocyte by increasing the alkaline phosphatase activity by 1.6 fold compared with control at the concentration of 50~500 ${\mu}g/ml$. Fr. Na generated 15.9 ${\mu}M$ of nitric oxide (NO) when cultured with RAW 264.7 at the concentration of 200 ${\mu}g/ml$, while lipopolysaccharide, a positive control, produced 3.7 ${\mu}M$. The Fr. NaCl, Fr. HW and Fr. MeOH increased the secretion of TNF-${\alpha}$, IL-$1{\beta}$, Il-2 and IL-6 by 2.2 times compared with the control group. Fr. Na increased the numbers of peritoneal exudate cells by 4 folds at the concentration of 50mg/kg compared with control. Circulating leukocytes increased by 2.7 folds when Fr. HW from A. brasiliensis was inoculated at the concentration of 50 mg/kg body weight. The hematological and blood chemical analysis of the 3 fractions did not show any difference in blood compositions and enzyme activities compared with the control group (p<0.05). Therefore, the experimental results suggested that crude polysaccharides extracted from A. brasiliensis contain antitumor and immuno-potentiating activities against Sarcoma 180 in ICR mice.

• Korean Journal of Environmental Biology
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• v.38 no.2
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• pp.299-307
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• 2020

This study reported on the phytoplankton community and seasonal changes in the Seoul passage section and downstream in the Han River in 2012. Field samples were collected monthly from the upper (Paldang), middle (Cheongdam), and downstream(Seongsan) areas of the Seoul passage section. Water temperature, DO, pH, and conductivity were measured at each station. All environmental factors measured were recorded similarly at the three stations. The water temperature ranged from 2 to 30℃ and the dissolved oxygen ranged from 4.8 to 9.1 mg L^-1, showing typical patterns of temperate regions. The phytoplankton cell concentrations ranged from 990 cells mL^-1 (Paldang, December) to 2.9×10⁴ cells mL^-1 (Seongsan, March), and the chlorophyll-a content showed similar patterns to the cell numbers. The phytoplankton community was comprised of 75 genera and 95 species, including 37 diatoms, 29 Chlorophyta, 11 cyanobacteria, and two dinoflagellates. The number of species that appeared seasonally varied greatly, from nine species (Paldang, May) to 35 species (Cheongdam, December). Diatoms were the most dominant in all stations and seasons, except in summer. In contrast, chlorophytes and cyanobacteria showed sporadic high numbers in the summer and fall seasons. Four diatoms Stephanodiscus hantzschii f. tenuis, S. hantzschii, Fragilaria sp., and Aulacoseira spp., a chlorophyte Actinastrum hantzschii, and a cyanobacterium Microcystis sp. were each present in proportions greater than 10%. This study provides fundamental data from phytoplankton communities and environmental factors in the Han River for understanding water quality for long-term environmental monitoring.

• Applied Biological Chemistry
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• v.46 no.3
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• pp.201-206
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• 2003

An apple wine was prepared by fermentation at $25^{\circ}C$ for 2 weeks using Saccha개myces cerevisiae KCCM 12224, followed by aging at $15^{\circ}C$ for 14 weeks, and its physicochemical and microbiological changes were investigated. The viable bacterial cell numbers, increased from $1.4{\times}10^3\;CFU/ml$ at the beginning of fermentation, to $2.8{\times}10^6\;CFU/ml$ after 2 weeks, but decreased to $1.0{\times}10^5\;CFU/ml$ after aging. The viable yeast cell numbers changed from $4.3{\times}10^4\;CFU/ml$ to $1.2{\times}10^7\;CFU/ml$ during the fermentation, and decreased to $1.2{\times}10^4\;CFU/ml$ after aging. Sugar content changed from $20.0^{\circ}Brix$ to $8.5{\circ}Brix$, and reducing sugar content was changed from 9.66% to 6.44%. Alcohol content and acidity increased to 7.0% and from 0.19% to 0.24%, respectively. No changes in acidity, pH, and sugar content were observed during the aging, but reducing sugar and solid contents decreased. When apple wine was fultered through $0.45\;{\mu}m$ nitrocellulose membrane followed by various ultrafiltration membranes with different molecular weight cut-off values, the initial flux $(121.2\;liter/m^2/h)$ and the average flux of Biomax 100k membrane were the highest among the membranes used. These membrane filtration treatments resulted in complete removal of microorganisms as well as decrease in turbidity and solid content without changes in other chemical properties. No changes in the physicochemical properties of the apple wine and no microorganisms were detected during the storage at $156{\circ}C$ for 6 weeks.

• Journal of Aquaculture
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• v.8 no.1
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• pp.47-58
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• 1995

Field studies on the seasonal succesion of phytoplankton population were carried out at the 25 stations of the breeding ground in Kogum-sudo, Southern coast of Korean peninsula in Feburuary, April, August and October, 1993. Sixty four species belonging to 40 genera were identified. Predominant species were mainly centric diatoms throughout the four seasons, two centric diatoms, Skeletonema costatum and Thalassiosira sp. and a pennate diatom, Thaiassionema nitzschioides in the winter; two pennate diatoms, Thaiassionema nitzschioides and Asterionella kariana, and especially a dinoflagellate, Heterocapsa triquetra (station 10) in the spring, two centric diatoms, S. costatum and Chaetoceros diadema in the summer; and a centric diatom, Rhizosolenia alata and a pennate diatom, Bacillaria paxillifer in the fall. The main red tide organisms in the breeding ground were dinoflagellates, Prorocentrum dentatum, P. minimum, P. triestinum, Ceratium furro, Gymnodinium sanguineum, Noctiluca scintillans, H. triquetra, Scrippsiella trichoidea and a diatom S. costatum in the Kogum Sudo. Seasonal phytoplankton cell numbers were in a wide range between $8.8\times10^3$ cells/l and 1.4\times10^6$ cells/l; The seasonal average cell numbers were $12.2\times10^4\pm5.9\times10^4$ cells/l $(mean\;\pm\;standard\; diviation)$ in the winter, $3.3\times10^4\pm1.4\times10^4$ cells/l in the spring, $48.4X10^4\pm40.0\pm10^4$ cells/l in the summer, and $3.6\times10^4\pm1.9\times10^4$ cells/l in the fall, respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.5
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• pp.776-781
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• 2010

The properties and bactericidal activities of strongly acidic electrolyzed water (SEW) against food-borne pathogenic bacteria, vegetables and kitchen apparatuses were investigated. The available chlorine concentration, pH and oxidation reduction potential (ORP) of SEW were $35{\pm}1.2\;ppm$, $2.3{\pm}0.2$, and $1,140{\pm}20.4\;mV$, respectively. Five strains of food-borne bacteria with initial cell number of 7.00 log CFU/mL were not detected except Bacillus cereus after treatment with SEW for 60 sec. The numbers of Bacillus cereus were reduced to 2.08{\pm}1.00 log CFU/mL at the same condition. In vegetables, SEW treatment after washing strongly in alkalic electrolyzed water (AEW) showed better bactericidal effects than SEW only. The viable cell on stainless steel bowl ($3.86{\pm}2.49\;\log\;CFU/100\;cm^2$) and cup for water ($2.40{\pm}1.80\;\log\;CFU/100\;cm^2$) were not detected by SEW treatment (35 ppm of available chlorine concentration) for 30 sec, but survival of more than 1.00 log CFU/$100\;cm^2$ of viable cell was shown by washing of sodium hypochlorite solution at the same condition. On the other hand, the coliform group bacteria ($5.08{\pm}4.00\;CFU/100\;cm^2$) were detected on rubber globe only, and more than 2.00 log CFU/$100\;cm^2$ of viable cell and coliform group bacteria on it survived, though it was washed with flowing SEW for 30 sec.