• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.513-523
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• 2017

We evaluated the viability of phytoplankton along the salinity gradient in the flood and ebb tides of spring tide of February and the ebb tide of neap tide of March 2017 in the Seomjin River Estuary. Additional laboratory experiments were also conducted to determine the reason of the pH changes along the salinity gradient using the field natural sample in February. In field, saltwater was well mixed at downstream vertically and the salinity gradient was horizontally appeared toward upstream of freshwater zone. There were strong negative correlations between salinity and nutrient (nitrate + nitrite R=0.99, p<0.001, and silicate R=0.98, p<0.001), implying that those two nutrients of freshwater origin were gradually diluted with mixing the saltwater. On the other hands, relatively high phosphate concentration was kept in the stations of saltwater over 15 psu, indicating that it was caused by resuspended sediments of Gwangyang Bay and downstream by tidal water mixing.Among phytoplankton community structure in winter, Eucampia zodiacus have occupied to be c.a. 70 % in the most stations. Based on the field survey results for survivability of phytoplankton by phytoPAM instrument, there was positive correlations between salinity and chlorophyll a (R=0.82, p<0.001) and, salinity and active chlorophyll a (R=0.80, p<0.001), implying that the dominant marine diatom species may have significantly damaged in low salinity conditions of upstream. Also, maximum mortality rate of phytoplankton caused by low salinity shock was appered to be 75% in the upstream station. In particular, the pH in spring tides of February had tended to increase with high phytoplankton accmulated stations, suggesting that it was related with absorption of $CO_2$ by the photosynthesis of dominant diatom. In laboratory experiments, phytoplankton mass-mortality caused by low salinity shock was also occurred, which is confirmed with reducing the photosynthetic electron transport activity. Following the phytoplankton mass-mortality, bacteria abundance was significantly increased in 24 hours. As a result, the mass-proliferating bacteria can produce the $CO_2$ in the process of biodegradation of diatoms, which can lead to pH decrease. Therefore, marine phytoplankton species was greatly damaged in freshwater mixing area, depending on along the salinity gradient that was considered to be an important role in elevating and reducing of pH in Seomjin River Estuary.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.1-6
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• 2011

This study was conducted to evaluate the antioxidant activity of liquid beni-koji (LBK), 70% ethanol extracts of beni-koji (EEB) and water extract of Hwangki (WEH). The yields of freeze dried powder of LBK, EEB and WEH were 32.17 g/L, 23.61 g/kg and 196.33 g/kg, respectively. Electron donating ability at 1% (w/v) of LBK, EEB and WEH were 82.67%, 15.71% and 8.60%; reducing power (OD700) were 2.06, 1.64 and 0.45, respectively. SOD-like activities were 24.32%, 11.11%, and 17.94%; nitrite scavenging activities were 74.92%, 72.31% and 31.83%, respectively. TBARS (%) were in order of LBK (69.65%)> EEB (67.32%)> WEH (4.42%). Electron donating ability at 1% (w/v) of EEB : WEH (1:1, w/w. EW), LBK : WEH (1:1, w/w. LW), EEB : LBK: WEH (1:1:1, w/w. ELW) were 14.58%, 60.66% and 20.42%; reducing power ($OD_{700}$) were 1.06, 2.01 and 1.71; SOD-like activities were 18.50%, 26.94% and 18.25%, respectively. While nitrite scavenging activities and TBARS (%) of ELW was higher than those of other materials. Total polyphenol content of LBK, EEB, WEH, EW, LW, ELW were 3.98%, 3.61%, 3.02%, 3.23%, 3.46% and 3.38%; total flavonoid content were 0.89%, 3.91%, 0.30%, 2.59%, 0.46% and 2.33%, respectively. In conclusion, this study provides experimental evidence that mixture of LBK, EEB and WEH could be used as a source of antioxidant ingredients in the food industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.9
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• pp.1369-1379
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• 2014

The physicochemical characteristics and antioxidant activities of leaf, stem, and root of ginger (Zingiber officinale R.) were determined. Nutrient composition, reducing sugar, saponin, mineral, heavy metal, total phenolic and total flavonoid contents, and antioxidant activities based on DPPH radical scavenging and FRAP assay were measured. Catechins, gingerols, shogaols, and capsaicin compositions were also determined by HPLC. The contents of water, proteins, fats, carbohydrates, fiber, and ash from ginger root were 6.4, 6.8, 3.2, 65.4, 7.3, and 18.2%, respectively. Crude fiber contents of leaf and stem were 4~5 times higher than those of root (P<0.05), and reducing sugar content of stem was about 3 times higher than those of root. Crude saponin contents were in the order of stem

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.9
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• pp.1174-1181
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• 2008

Garlics were aged at 60, 70, 80, and $90^{\circ}C$ for 1, 3 and 6 days. Samples were analyzed for physico-chemical components and antioxidant activities, such as DPPH scavenging activity and reducing power of hot water and ethanol extracts. The Hunter L, a and b values were significantly lower in sample aged at higher temperature and for longer time. In initiation of aging, the share force was the lowest in sample aged at $90^{\circ}C(85.70{\pm}1.44\;kg/cm^2)$ and it increased for 6 days to $411.30{\pm}13.90\;kg/cm^2$ in aging. The pH of garlic was acidified at increasing aged temperature and periods. In sample aged for 6 days at $60^{\circ}C$ and $90^{\circ}C$, pH was 6.12 and 3.90, respectively. Contents of total phenolics and flavonoids also increased in sample aged at higher temperature and for longer time. Their contents increased about 3.5 and 9.1 times higher in sample aged for 6 days at $90^{\circ}C$ than sample aged for 6 days at $60^{\circ}C$, respectively. Total pyruvate contents were fluctuated by aging temperature and periods. DPPH scavenging activity was increased in sample aged at higher temperature and longer time. The highest activity of DPPH scavenging showed $87.48{\pm}0.20%$ in sample aged for 6 days at $90^{\circ}C$. Similar results were observed in reducing power activity. It was estimated that such increases in anti-oxidant activities in aged garlics may come from actions of phenolics, flavonoids and browning compounds in them.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.334-341
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• 1997

Artificial precipitation test with sprinkler system was carried out to develop the collection method of arboreal larvae(proctotrupoid wasps) of pine needle gall midge for biological control in 1995. Effects of larvae falling on each amount of precipitation, season of precipitation and time of precipitation of a day following artificial precipitation were examined during the period of larvae falling season. The results obtained were summarized as follows; 1. Artificial precipitation with sprinkler system was highly effective for collection of pine needle gall midge larvae and the most suitable amount of precipitation was 5.3-9.4mm; application amount and hours of water were $8,000-16.000{\ell}$ and 180-360 minutes, respectively. 2. The most effective period of larvae collection for artificial precipitation was approximately 20 days, from early through mid November, and larvae falling was 93.4% of the total number of larvae collection during this period. 3. Larvae falling from the tree crown was not affected by the artificial precipitation for the precipitation hour intervals in a day. 4. The percentage of parasitism of collected larvae of pine needle gall midge in November exceeded that of December but was not significantly different between two seasons. 5. Artificial precipitation of sprinkler system was effective in reducing 34% of gall formation after one year at collected sites of pine needle gall midge larvae. 6. The collection method of larvae following artificial precipitation was effective in reducing the expenses by 14-50% than that of collection method of infested needles.

• Economic and Environmental Geology
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• v.43 no.1
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• pp.13-20
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• 2010

Acid mine drainage (AMD) from abandoned mine sites typically has low pH and contains high level of various heavy metals, aggravating ground- and surface water qualities and neighboring environments. This study investigated removal of heavy metals in a biological treatment system, mainly focusing on the removal by adsorption on a substrate material. Bench-scale batch experiments were performed with a mushroom compost to evaluate the adsorption characteristics of heavy metals leached out from a mine tailing sample and the role of SRB in the overall removal process. In addition, adsorption experiments were perform using an artificial AMD sample containing $Cd^{2+}$, $Cu^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ to assess adsorption capacity of the mushroom compost. The results indicated Mn leached out from mine tailing was not subject to microbial stabilization or adsorption onto mushroom compost while microbially mediated stabilization played an important role in the removal of Zn. Fe leaching significantly increased in the presence of microbes as compared to autoclaved samples, and this was attributed to dissolution of Fe minerals in the mine tailing in a response to the depletion of $Fe^{3+}$ by iron reduction bacteria. Measurement of oxidation reduction potential (ORP) and pH indicated the reactive mixture maintained reducing condition and moderate pH during the reaction. The results of the adsorption experiments involving artificial AMD sample indicated adsorption removal efficiency was greater than 90% at pH 6 condition, but it decreased at pH 3 condition.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.504-510
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• 2015

This study was carried out to investigate the antioxidant effects of different parts (stems, leaves, and seeds) of the black raspberry for utilization as food materials. Different parts of the black raspberry were subjected to extraction via ultra-sonication extraction methods using water and ethanol at various concentrations (25, 50, 75, and 100%). Antioxidant capability of the extracts were determined by amounts of phenolic compounds, with flavonoid contents, radical scavenging activity, and reducing power. Irrespectively of ethanol concentration, extracts of stem showed the highest total phenolic compounds and antioxidant activities among different parts of black raspberry. The total phenolic compounds extracted from the black raspberry stem using 25 and 50% ethanol showed $348.21{\pm}5.40$ and $343.39{\pm}5.94mg/g$, respectively. Fifty percent ethanol extracts of the black raspberry stem showed the highest DPPH ($EC_{50}$ value: $60.89{\mu}g/mL$) and ABTS radical scavenging activities ($EC_{50}$ value: $82.57{\mu}g/mL$). Further, 25% ethanol extacts of the black raspberry stem ($0.263{\pm}0.004$) was found to have the highest reducing power. The highest antioxidant activity of black raspberry stem indicates that black raspberry stem may be useful source for functional food.

• Journal of Life Science
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• v.26 no.9
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• pp.1033-1040
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• 2016

In Korea, the aerial parts of the halophyte Salicornia europaea, known as hamcho, are used in salads in April–June and in oriental medicine in September–October In this study, with the aim of developing functional foods to aid blood circulation, hot water extract (HWE) and ethanol extract (EE) were prepared using hamcho harvested from the fields of Shinan, Jeonnam, Korea on 5th April (HWE-04, EE-04), 5th July (HWE-06, EE-06), 5th August (HWE-08, EE-08), 5th September (HWE-09, EE-09), and 5th October (HWE-10, EE-10), and their antioxidant and antithrombosis activities were evaluated. Among the HWEs, HWE-10 showed the highest concentration of total polyphenols and total flavonoids (22.4 and 17.6 mg/ml, respectively), and EE-09 had the highest concentration among the EEs (20.1 and 19.3 mg/ml, respectively). Among the HWEs and EEs, HWE-08 and EE-08 had the highest total sugar and reducing sugar content. In the antioxidation assay, HWE-10 and EE-09 showed strong reducing power, as well as DPPH, ABTS, and nitrite scavenging activities. The calculated RC₅₀s of EE-09 against DPPH, ABTS, and nitrite were 578, 277, and 68.8 μg/ml, respectively. The antithrombosis activity assay revealed that HWE-04, HWE-06, EE-04, and EE-06 had anticoagulation activity against coagulation factors and that HWE-08, HWE-09, EE-08, and EE-09 expressed strong thrombin inhibitory activity, which was comparable to the antithrombosis activity of aspirin. In addition, EE-06 and HWE-08 exhibited strong aggregation inhibitory activities against human platelets. The results suggest that extract from hamcho harvested in particular periods and prepared using a defined solvent has strong potential as a novel food ingredient and an antioxidant and antithrombosis agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.11
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• pp.1571-1579
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• 2009

Antioxidant activities of ethanol and water extracts from Orostachys japonicus leaf, stem, and root were determined by rancimat method, DPPH radical scavenging effect, chelating effect, and reducing power analysis. The highest total phenolic compound (TPC) as 14.6 mg/g of dry sample and the strongest antioxidant activity in rancimat method (value of AI 1.98), DPPH radical scavenging effect (96% in 4 mg/mL), and reducing power (1.50 in 4 mg/mL) were observed in ethanol extracts from Orostachys japonicus leaf. Heat and pH stabilities on antioxidant activity of Orostachys japonicus leaf extract were studied through TPC and DPPH radical scavenging effect. As a result, the extracts from Orostachys japonicus leaf showed high stability. These results suggest that extracts from Orostachys japonicus leaf can be potentially used as proper natural antioxidant in the food industry.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.60-71
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• 2014

This study was conducted to identify the potential of rape stalk as a raw material for biorefinery process of rape flower. At first, rape stalk (RS) was immersed in distilled water (DW), acetic acid (AA), oxalic acid (OA), sulfuric acid (SA) and sodium hydroxide (SH) solutions, and the content of reducing sugars liberated from immersed RS was analyzed. Glucose, xylose, arabinose and sucrose were detected varying with the immersion type. In particular, 1% AA-immersion of RS for 72 hr was the most effective conditions to liberate glucose from RS. Secondly, the RS residues were used for elementary analysis and fabrication of fuel pellets. In addition to the solution type, concentration of immersion solutions (0%, 1%, 2%) and immersion time (24, 72, 120 hr) were used as experimental factors. The contents of nitrogen, sulfur and chlorine reduced effectively through the immersion of RS in DW, AA and OA solutions. For properties of RS-based pellets, bulk density and higher heating value of RS-based pellets greatly increased with the immersion of RS, and the qualities were much higher than those of the A-grade pellet of the EN standards. Ash content decreased remarkably through the immersion of RS, and was satisfied with the A-grade pellet standard. Durability was negatively affected by the immersion of RS, and did not reached to B-grade of the EN standard. In conclusion, acid immersion of RS can be a pretreatment method for the production of fuel pellet and bioethanol, but use of the immersed RS for the production of high-quality pellets might be restricted due to low durability of immersed-RS pellets. Therefore, further studies, such as investigation of detailed immersion conditions, fabrication of mixed pellets with wooden materials and addition of binders, are needed to resolve the problems.