• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.5
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• pp.767-774
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• 2015

In recent decades, health concerns related to sodium intake have caused an increased demand for salt or sodium-reduced foods. Umami substance can enhance taste sensitivity to NaCl and may offer a unique approach to replace and reduce the sodium content in foods. In this study, hot water extraction conditions of Wando sea tangle with high umami taste were investigated. Wando sea tangle harvested in June was selected for hot water extraction based on its free amino acids composition. The quality properties of sea tangle extract were investigated at various extraction temperatures ($60^{\circ}C$, $80^{\circ}C$, and $100^{\circ}C$) and times (1 h, 2 h, and 3 h). Sea tangle extracts at the extraction temperature of $100^{\circ}C$ contained the highest soluble solids (35.47%~36.93%), and crude protein (3.75%~4.00%). Viscosities of sea tangle extracts decreased with increasing extraction temperature. Umami amino acids (glutamic acid and aspartic acid) and sensory characteristics were best at extraction conditions of $100^{\circ}C$ for 2 h. Saltiness enhancement of sea tangle extract powder was determined. Saltiness intensities of NaCl solution after adding 1% sea tangle extract powder were enhanced (1.84~4.25-fold). At the same saltiness intensity, sodium contents of NaCl solution with 1% sea tangle extract powder were 12.24~24.33% lower than that of NaCl solution. These results suggest that it is possible to reduce sodium in foods with sea tangle extract as a natural salt enhancer without lowering overall taste intensity.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.2
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• pp.68-77
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• 2002

We investigated the outbreak, maintenance, and decline of the red tide dominated by C. polykrikoides in the coastal waters off Southern Korea from August to October, 2000, by combining field data and NOAA satellite images. In general, the C. polykrikoides blooms, which have occured annually in Korean coastal waters from 1995 to 1999, initiate between late August and early September around Narodo Island and expand to the whole area of the southern coast. However, initiation and short-term change of the bloom of 2000 were quite different from the pattern observed previously. In mid-August, thermal fronts in sea surface temperature(SST) were formed: 1) between the Tsushima Warm Current Water (TWCW) and the Southern Korean Coastal Waters (SKCW), 2) between the jindo cold water mass and the southwestern coastal waters, and 3) between the upwelled cold waters in the southeast coast and the offshore warm waters. Free-living cells of C. polykrikoides were concentrated in these frontal regions. In late August, the thermal front TWCW-SKCW approached the mouth of Yeosuhae Bay where Seomjin River water and anthropogenic pollutants from the Industrial Complex of Gwangyang Bay are discharged. In the blooms of 2000 initiated in Yeosuhae Bay in late August, the dominant species, C. polykrikoides, co-occured with Alexandrum tamarense, Gymnodinium mikimotoi, Skeletonema coastatum, and Chaetoceros spp. Two typhoons, 'Prapiroon' and 'Saomai' during and the C. polykrikoides bloom probably affected the abundance of this species. After the former typhoon passed the Korean Peninsula, cell growth of C. polykrikoides was maximal, but after the latter typhoon, the C. polykrikoides bloom disappeared (20 September). On 5 October, the blooms dominated by C. polykrikoides broke out within the coastal waters of Jinhae Bay and Hansan-Keoje Bay. NOAA satellite images showed that the isothermal line of 22$^{\circ}C$ extended into Jinhae Bay. In this bloom, C. polykrikoides also occurred simultaneously with Akashiwo sanguinea(=Gym-nodinium sangunium), a common red tide-forming dinoflagellate species in fall and winter in these coastal bays.

• Journal of Life Science
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• v.18 no.12
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• pp.1718-1721
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• 2008

The skin of human is constantly being exposed to environmental irritants such as ultraviolet, smoke and chemicals. These irritants cause free radicals and reactive oxygen species which leave serious damages on the cells of skin. The water and ethanol extracts of Cambodian Phellinus linteus were investigated for the activities of anti-lipid peroxidation and anti-wrinkle effects to apply as a functional ingredient for cosmetic products. As the result of evaluation of liquid oxidation rate by add $Fe^{2+}$ and $Cu^{2+}$ to Cambodian Phellinus linteus extracts, Cambodian Phellinus linteus ethanol extracts were higher than Cambodian Phellinus linteus water extracts in the chealting ability of $Fe^{2+}$ and $Cu^{2+}$. The Cambodian Phellinus linteus ethanol extracts exhibited that anti-lipid peroxidation higher than butylated hydroxytoluene (BHT) at the concentration of 0.1 mg/ml, 0.5 mg/ml and 1 mg/ml. Cambodian Phellinus linteus water and ethanol extracts showed a higher inhibitory effect on $Fe^{2+}$-induced lipid peroxidation compared to $Cu^{2+}$-induced lipid peroxidation. In the case of anti-wrinkle effect, the elastase inhibition activity of Cambodian Phellinus linteus ethanol extracts was 50.7%, and it is higher than urosolic acid at the concentration of 0.01 mg/ml. Also, in collagenase inhibition activity, Cambodian Phellinus linteus water extract showed low effect, but Cambodian Phellinus linteus ethanol extract was about 50% at a 0.1 mg/ml. concentration. These results proved that Cambodian Phellinus linteus had anti-lipid peroxidation and anti-wrinkle effect. Therefore, Cambodian Phellinus linteus could be useful as an anti-wrinkle cosmetic ingredient.

• Korean Journal of Weed Science
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• v.15 no.4
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• pp.289-297
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• 1995

Field experiments were conducted to evaluate the competitive characteristics of weeds with direct-seeded rice. In both dry- and water-seeded rice a weeds) started to grow over the plant height of rice from 45 days after seeding, and there was a great difference in plant height between rice and weeds from 75 days after seeding. Dry weights of weeds drastically increased from 30 days after seeding in both dry- and water-seeded rice, and the increase of dry weight was faster in dry-seeded rice than in water-seeded rice with time. Although weeds competed with rice at earlier growth stages, they did not reduce rice yields and its components until competition period of 75 days after seeding. Required period of weed free at the beginning of the season was 30 to 45 days from seeding in order to avoid any yield loss. The numbers of panicle per plant, spikelets per panicle, grain weight and yield of rice in dry-seeded rice had highly negative correlations with the growth ratios of Echinochloa crus-galli, Ludwigia prostrata, Cyperus difformis, Bidens frondosa, and Cyperus serotinus. In water-seeded rice, the number of plants, panicle per plant, spikelets per panicle and yield had highly negative correlations with growth rate of Echinochloa crus-galli, but the percentage of filled spikelet had negative correlation with Cyperus difformis. Research indicated that in direct-seeded rice weed competition with rice started from 30 days after seeding and significant yield loss by weed competition occurred from 75 days after seeding.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.92-102
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• 2002

This study was conducted to compare filtering abilities of three species of freshwater mussels (Cobicula fluminea, Corbicula leana and Unio douglasiae) and to evaluate their filter feeding effects on water quality change in experimental enclosure systems. Mussel feeding in both laboratory and enclosure resulted in decrease of particulate material, such as chlorophyll, total P, SS. In the treatment with 600 individuals of mussels, chllorophyll concentration and net primary productivity decreased from $87.3{\pm}4.5\;{\mu}g/L$ and $106.3{\pm}8.8\;{\mu}gC\;L^{-1}\;hr^{-1}$ to nearly the same level as the mussel-free enclosure ($25.0{\pm}0.5\;{\mu}g/L$ and $15.6{\pm}13.3\;{\mu}gC\;L^{-1}\;hr^{-1}$, respectively)(P< 0.05, n = 6, ANOVA). In concert with the decrease of chlorophyll concentration, not only was the transparency enhanced from 0.48 m to 1.2m but also the suspended solids and total phosphorus decreased from $22.0{\pm}1.0\;mg/L$ to $7.5{\pm}0.5\;mg/L$ and $133{\pm}0.8\;{\mu}g/L$ to $70{\pm}0.0\;{\mu}g/L$, respectively (P<0.001, $r^2$>0.71, n = 11). Although slight decrease of SRP concentration and the increase of inorganic nitrogen ($NH_3-N$ and $NO_2-N$) were observed in the mussel addition enclosure, there was no statistical difference between two enclosures. Based on the filtering rate on phytoplankton and nutrient release rate in forms of feces and pseudofeces, Corbicula leana appeared to be the most efficient filter-feeder among three mussel species. These results inidicate that Cobicula play an important role in controlling particulate sestons and thus it could be applied as a biocontroler for the water quality management in lakes and reservoirs with algal blooms.

• Korean Journal of Plant Resources
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• v.30 no.4
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• pp.335-342
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• 2017

Spiraea prunifolia Sieb. et Zucc. var. simpliciflora Nakai (SSN) has been used for the anti-inflammation in traditional folk medicine. To compare water and methanol extracts of SSN, we analyzed major components using LC IT TOF MS. The major components of hot water extract were identified as caffeic acid and p-coumaric acid, but methanol extract was not well established. However, methanol extract was detected with less polarity compounds compared to hot water extract. Next, we investigated the inhibitory effects of SSN water extract on the lipopolysaccharide (LPS)-induced inflammatory response or $H_2O_2-induced$ oxidative stress in Raw 264.7 macrophage cells. SSN strongly suppressed the production of nitric oxide in LPS-induced inflammatory response without cytotoxcity. The SSN possessed free radical scavenging activities such as DPPH ($IC_{50}=320.2{\mu}g/m{\ell}$), ABTS ($IC_{50}=124.0{\mu}g/m{\ell}$), and superoxide anion radical ($IC_{50}=122.6{\mu}g/m{\ell}$). The total phenol and flavonoid content of SSN was 56.7 mg/g, and 15.1 mg/g, respectively. Furthermore, SSN decreased the $H_2O_2-induced$ cytotoxicity by enhancing the cell viability, and SSN significantly reduced the intracellular reactive oxygen species (ROS) level. Therefore, SSN may be recommended as an effective strategy to prevent and/or treat various inflammation and ROS-induced diseases.

• Food Science and Preservation
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• v.22 no.1
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• pp.63-69
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• 2015

The highly producible rice cultivars, hanareum and dasan 2, were prepared and investigated for their physicochemical properties, and the quality characteristics of frozen cookie dough with rice flour according to the thawing time were measured. The water, ash, crude protein, amylose, and damaged starch contents of rice flour, as well as its water holding capacity, particle size, and Hunter color value, were measured. The water, ash, and crude protein contents of the hanareum and dasan 2 rice flours were shown to range from 7.28 to 13.14%, from 0.35 to 0.39, and from 6.05 and 8.68%, respectively. The protein content of the control group was higher than that of hanareum and dasan 2 rice flours. The amylose contents of the hanareum and dasan 2 rice flour were 19.05 and 23.04%, respectively. The damaged starch content and water holding capacity of the control group were lower than those of the hanareum and dasan 2 rice flours. The particle sizes of the samples were $48.54{\sim}50.05{\mu}m$. The lightness values of the hanareum, and dasan 2 rice flour, and of the control were 93.72, 93.51 and 92.63, respectively. The quality characteristics of the gluten-free frozen cookie dough were investigated. The lightness of the cookie made with frozen cookie dough decreased according to the by thawing time, but the diameter of the cookie did not differ significantly. The hardness of the cookie made with rice frozen dasan 2 rice dough was lower than that of the cookie made with frozen hanareum rice dough.

• Korean Journal of Medicinal Crop Science
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• v.13 no.6
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• pp.255-260
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• 2005

For selecting a new candidate as functional material, this study was conducted on in vitro antioxidant activity and total phenol content of methanol and water extracts prepared from two Mentha species (M viridis L. (M spicata L.) and Mentha piperita L, Extracts of M. viridis showed more efficient scavenging activity on superoxide and DPPH ${({\alpha},{\alpha}-diphenyl-{\beta}-picrylhydrazyl)}$ radical and inhibitory activity on oxidation of human low density lipoprotein (LDL) induced by $CuSO_4$ and auto-oxidation of linoleic acid than those of M piprita. Methanol extract $(65.88%{\sim}77.59%)$ and water extract $(37.69%{\sim}87.21%)$ of M. viridis also exhibited more potent inhibitory activity on LDL oxidation than that of ${{\alpha}-tocopherol\;(28.37%{\sim}66.54%)}$ at ${1{\sim}100\;{\mu}g/ml}$ of final concentration. The total phenol contents of methanol extract and water extract of Mviridis (17.95% & 10.18%, respectively) as tannic acid equivalent were higher than those of M piperita (15.44% & 9.19%). But the yields of methanol and water extracts of M. viridis (13.3 % & 13.5%) were lower than those of M. piperita (14.1 % & 14.6%). The results implies that the extracts from M. viridis (spicata) is more useful material for industrialization as functional food than those from M. piperita.

• The Korean Journal of Mycology
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• v.47 no.1
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• pp.51-61
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• 2019

The goal of this study was to elucidate wild yeast diversity of Geumgang midstream near Sejong metropolitan autonomous city, Korea. Thirty-seven strains of 32 species of wild yeasts were isolated from 43 water and soil samples under the Bulti bridge of Sejong city, Korea. Seven yeasts of each Candida spp. and Cryptococcus spp. were the predominant species isolated from samples near the Bulti bridge. Holtermanniella takashimae SW048 (NNIBRFG9314), Cystofilobasidium infirmominiatum SW013 (NNIBRFG9310), Mrakia cryoconite SW015 (NNIBRFG9316), Pichia sporocuriosa SW085 (NNIBRFG9326) and Cryptococcus aspenensis SW008 (NNIBRFG9309) represented novel yeast strains found in Korea for the first time. All of these previously unrecorded yeasts, except for Mrakia cryoconite SW015 had ascospores and grew well in yeast extract-peptone-dextrose (YPD), yeast extract-malt extract (YM) and potato-extrose (PD) media. Pichia sporocuriosa SW085 grew well in vitamin-free medium and Holtermanniella takashimae SW048, which was a halotolerant wild yeast, grew well YPD medium containing 5 % NaCl. Twenty-six strains representing eight species of wild yeast were isolated from 22 water and soil samples under the Haetmuri bridge of Sejong city, Korea. Candida pseudolambica (12 strains) and Aureobasidium pullulans (11 strains) were the predominant isolates from samples near the Haetmuri bridge. Occultifur kilbournensis HB060 (NNIBRFG9317), Sampaiozyma vanillica HB014 (NNIBRFG9332), Xenoramularia neerlandica HB039 (NNIBRFG9335), Candida norvegica HB315 (NNIBRFG9306), C. melibiosica HB316 (NNIBRFG9305), C. quercuum GB014 (NNIBRFG9307), and C. succiphila GB015 (NNIBRFG9308) represented novel yeast strains recorded in Korea for the first time. O. kilbournensis HB060 and X. neerlandica HB039 did not form ascospores or pseudo-mycelia. All of these previously unrecorded yeasts, except S. vanillica HB014 and X. neerlandica HB039, grew well in vitaminfree medium, and C. norvegica HB315 and C. succiphila GB015, which were halotolerant wild yeasts, which grew well in YPD medium containing 5 % NaCl.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.3
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• pp.313-331
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• 2022

Natural or native abiotic molecular hydrogen (H₂) is a major component in natural gas, however yet its importance in the global energy sector's usage as clean and renewable energy is underestimated. Here we review the occurrence and geological settings of native hydrogen to demonstrate the much widesprease H₂ occurrence in nature by comparison with previous estimations. Three main types of source rocks have been identified: (1) ultramafic rocks; (2) cratons comprising iron (Fe²⁺)-rich rocks; and (3) uranium-rich rocks. The rocks are closely associated with Precambrian crystalline basement and serpentinized ultramafic rocks from ophiolite and peridotite either at mid-ocean ridges or within continental margin(Zgonnik, 2020). Inorganic geological processes producing H₂ in the source rocks include (a) the reduction of water during the oxidation of Fe²⁺ in minerals (e.g., olivine), (b) water splitting due to radioactive decay, (c) degassing of magma at low pressure, and (d) the reaction of water with surface radicals during mechanical breaking (e.g., fault) of silicate rocks. Native hydrogen are found as a free gas (51%), fluid inclusions in various rock types (29%), and dissolved gas in underground water (20%) (Zgonnik, 2020). Although research on H₂ has not yet been carried out in Korea, the potential H₂ reservoirs in the Gyeongsang Basin are highly probable based on geological and geochemical characteristics including occurrence of ultramafic rocks, inter-bedded basaltic layers and iron-copper deposits within thick sedimentary basin and igneous activities at an active continental margin during the Permian-Paleogene. The native hydrogen is expected to be clean and renewable energy source in the near future. Therefore it is clear that the origin and exploration of the native hydrogen, not yet been revealed by an integrated studies of rock-fluid interaction studies, are a field of special interest, regardless of the presence of economic native hydrogen reservoirs in Korea.