• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.355-360
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• 1997

In order to investigate the influence of photosensitized oxidation in the sun-dried irish moss (Chondrus Ocellatus), laver (Porphyra Yezoensis) and ultra violet irradiated oyster (Crassostrea gigas) the oxidation of lipid and isomers of hydroperoxides were analyzed by gas chromatography-mass spectrometry. The lipid contents of oyster, irish moss and layer were $2.7\%,\;0.1\%,\;0.1\%$ of respectively. Peroxide value, 56,7 meq/kg in the raw oyster was increased of 100.9 meq/kg by the U.V, irradiation for 4 hours. Also the peroxide values of the irish moss and laver were increased by the sun-drying. In the identification of hydroperoxides isomers by trimethylsily (TMS) derivative of photo-oxidized lipid from oyster, irish moss and laver, the proportions of positional isomer, 9-OOH and 13-OOH were dominant than those 10-OOH and 12-OOH.

• Korean Journal of Food Science and Technology
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• v.19 no.3
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• pp.206-211
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• 1987

In an attempt to improve the quality stability of dried layer (Porphyra yezoensis Ueda), during longterm storage and distribution, a 6 months storage trial at different temperature and packaging condition was conducted. Dried layer samples were prepared by conventional procedure with different washing condition and $5^{\circ}C$ and $30^{\circ}C$ were employed as storage temperature. The moisture sorption isotherm was drawn at $5^{\circ}C$ and $25^{\circ}C$ and BET equation was prepared from the moisture sorption isotherm. The monolayer moisture contents of dried layer were 7.4% at $5^{\circ}C$ and 6.4% at $25^{\circ}C$, respectively. It was also found that the changes in comprehensive quality of dried layer during storage was much less at low temperature and the degree of washing before drying process as far as its moisture contents are lower than monolayer moisture contents. With regard to the packing methods, vaccum packing was superior to air containing packaging for the maintainance of quality during storage.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.16 no.4
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• pp.335-340
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• 1983

The effects of water temperature, salinity, and silt and clay on the photosynthetic activity of Porphyra yezoensis were measured. The rate of photosynthesis of P. yezoensis increases as the water temperature rises in the range of $8{\sim}16^{\circ}C$ and begin to decrease at $18^{\circ}C$. In the salinity range of $21.5{\sim}33.5\%0$, the rate of photosythesis of P. yezoensis was increased in the sea water of $29.5\%0$ salinity and decreased in $21.5\%0$ salinity. The rates of photosynthesis of P. yezoensis were significantly decreased with increase of the concentration of silt and clay and the time of exposure to suspended silt and clay. Of the combined effects of salinity, and silt and clay on the photosynthetic activity of P. yezoensis, the effects of silt and clay were higher in the low salinity of $21.5\%0$ and $33.5\%0$. The wet weight of P. yezoensis showed a remarkable loss with increase of the concentration of silt and clay and the time of exposure to silt and clay.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.325-329
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• 2002

This study was carried out to investigate the effect of porphyran on enzyme activity in rats and immunity in mice. Animals were divided into 5 groups, and were given porphyran diet for 4 weeks. Porphyran was extracted from Porphyra yezoensis: Diet groups were normal diet, control diet fed high fat, cholesterol and sodium cholate, control and 1% porphyran diet (1% PD), control and 5% porphyran diet (5% PD), control and 10% of porphyran diet (10% PD). Also Balb/c female mouse were injected i.p. with porphyran extract every other day for 20 days at levels of 1%, 2% and 5%. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) activities were lower in the porphyran diet group than those in control group. Superoxide dismutase and catalase activities in liver homogenates were reduced in porphyran diet group compared to those of control group. Also, the level of liver thiobarbituric acid reactive substance (TBARS) was lower in porphyran group than that of control group. Porphyran increased IL-1 production in a dose-dependent manner, however, interleukine-2 production was reduced as the amount of porphyran increases. These results showed that supplementation of porphyran lowered antioxidant enzyme activities and has possibility of modulating immunological function.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.3
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• pp.237-247
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• 1987

The present study deals with the physico-chemical and meteorological conditions in Porphyra-cultivation ground to determine the relationship between laver production and its environmental factors in Kwangyang Bay from January to April in 1986. As a result, major environmental factors which are thought to have a great influence upon the poor harvest during the cultivation period are as follows; 1) the excessive rainfall in the beginning of cultivation period 2) the accumulation of suspended matters on the thallus of laver 3) the decrease of current velocity and the stagnation of the water in the cultivation ground.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.947-953
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• 2002

Two types of electronic nose were used for investigating the quality of dried lavers stored at 5, 15, and $30^{\circ}C$ RH of 32, 43, and 75%. The electronic nose is composed of metal oxide sensors, and GC is based on SAW sensor. Quality change in dried lavers was described in terms of the sensitivities $(R_{gas}/R_{air})$ of the sensors. Principal component analysis (PCA) was carried out using data obtained from six metal oxide sensors. The first principal component scores were correlated with quality changes of dried lavers. As storage time increased, the stored laver cluster separated from that of fresh lavers. A chromatogram was obtained from GC based on SAW sensor. Olfactory image, A $VaporPrint^{TM}$ image for pattern recognition, showed a significant difference between the stored and the fresh samples. Dried lavers during storage at $30^{\circ}C$ and 75% had bacterial counts of $5.7{\times}10^6\;CFU/g$ after 8 day. Increase of microbial count correlated with the response of electronic nose $(r^2=0.87)$. Whereas, color values showed no correlation.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.297-305
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• 2014

In order to understand the contribution of seaweed aquaculture to nutrients and carbon cycles in coastal environments, we measured the nutrients & carbon uptake rates of Porphyra yezoensis Ueda sampled at Nakdong-River Estuary using a chamber incubation method from November 2011 to April 2012. It was observed that the production rate of dissolved oxygen by P. yezoensis (n=30~40) was about $68.8{\pm}46.0{\mu}mol\;{g_{FW}}^{-1}h^{-1}$ and uptake rate of nitrate, phosphate and dissolved inorganic carbon (DIC) was found to be $2.5{\pm}1.8{\mu}mol\;{g_{FW}}^{-1}h^{-1}$, $0.18{\pm}0.11{\mu}mol\;{g_{FW}}^{-1}h^{-1}$ and $87.1{\pm}57.3{\mu}mol\;{g_{FW}}^{-1}h^{-1}$, respectively. There was a positive linear correlation existed between the production rate of dissolved oxygen and the consumption rates of nitrate, phosphate and DIC, respectively, suggesting that these factors may serve as good indicators of P. yezoensis photosynthesis. Further, there was a negative logarithmic relationship between fresh weight of thallus and uptake rates of nutrients and $CO_2$, which suggested that younger specimens (0.1~0.3 g) were much more efficient at nutrients and $CO_2$ uptake than old specimens. It means that the early culturing stage than harvesting season might have more possibilities to be developed chlorosis by high rates of nitrogen uptake. However, N & C demanding rates of Busan and Jeollabuk-do, calculated by monthly mass production and culturing area, were much higher than those of Jeollanam-do, the highest harvesting area in Korea. Chlorosis events at Jeollabuk-do recently might have developed by the reason that heavily culture in narrow area and insufficient nutrients in maximum yield season (Dec.~Jan.) due mostly to shortage of land discharge and weak water circulation. The annual DIC uptake by P. yezoensis in Nakdong-River Estuary was estimated about $5.6{\times}10^3\;CO_2$ ton, which was about 0.03% of annual carbon dioxide emission of Busan City. Taken together, we suggest more research would be helpful to gain deep insight to evaluate the roles of seaweed aquaculture to the coastal nutrients cycles and global carbon cycle.

• Journal of Life Science
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• v.28 no.2
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• pp.176-186
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• 2018

In this study, the total polyphenol contents, antioxidant activities and anti-proliferation effects of HepG2 cell lines in organic slovent fractions obtained from the main methanolic extract of P. yezoensis were analyzed. The polyphenol content of the $CHCl_3$ fraction was $10.3{\mu}g/mg$, slightly less than $13.08{\mu}g/mg$ of the water fraction, but $ED_{50}$ estimated by measuring DPPH free radical scavenging activity exhibited the highest $16.96{\mu}g/ml$ in the $CHCl_3$ fraction. The proliferation effects of $CHCl_3$ and EtOAc fraction toward HepG2 cells inhibited in a dose-dependent manner, showed 90% inhibition when treated for 24 hr at $900{\mu}g/ml$ of $CHCl_3$ fraction. Meanwhile gene expression patterns in HepG2 cells treated $50{\mu}g/ml$ of $CHCl_3$ fraction were identified with microarray analysis. Concerning the efficacy of P. yezoensis, gene ontology analysis explored the genes associated with response to molecule of bacterial origin, vitamin D metabolic process, and response to nutrient. Thus IL6R, CYP1A1 were selected as significant genes based on expression patterns of HepG2 cells, and pathway analysis indicates that ARNT might be considered as a upstream regulator. Also, expression analysis of IL6R and CYP1A1, activity of upstream regulator ARNT in HepG2 cells was confirmed based on Western blotting analysis at the protein level after being treated with 50 and $100{\mu}g/ml$ of $CHCl_3$ fraction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.7
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• pp.826-833
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• 2008

The effects of porphyran-chungkookjang on cytotoxicity of human normal cell line (BJ) and human cancer cell lines (AGS and HT-29) were examined. Porphyran, which was prepared from laver (Porphyra yezoensis), decreased the viability of the cancer cells, however, it did not affect the viability of normal cells. Porphyranchungkookjang was prepared by the addition of 5% (w/w) porphyran into chungkookjang which was fermented by starter, Bacillus subtilis DJI. The cytotoxicity effects of the chungkookjang and porphyran-chungkookjang were evaluated with MTT assay. The methanol and the water extract of porphyran-chungkookjang at 1.0 mg/mL showed $23{\sim}38%$ decreases in proliferation of cancer cells (AGS and HT-29). However, the methanol and the water extracts of porphyran-chungkookjang did not inhibit the growth of normal cell. Moreover, the methanol extract of porphryan-chungkookjang at 1.0 mg/mL showed $1.2{\sim}1.5$ fold higher anticancer effects than that of the chungkookjang.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.5
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• pp.469-475
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• 1987

The present paper was investigated to elucidate the nitrite-scavenging ability of seaweed extracts. Seaweed extracts possessed the scavenging ability of nitrite. By fractionation of seaweed extracts, nitrite-scavenging ability of laver(Porphyra tenera), sea lettuce(Enteromorpha compresa) extracts were effective in the water-soluble fraction, but sea mustard (Undaria pinnatifida), sea staghorn (Codium fragile) extracts in the methanol-soluble fraction. Nitrite scavenging ability of seaweed extracts was also pH-dependent, highest at pH1.2 and lowest at pH6.0. Particularly, nitrite-scavenging abilities of water-soluble fractions obtained from laver and sea lettuce were similar to that of L-ascorbic acid at pHl.2. After seaweed extracts were treated with sodium borohydride, nitrite-scavenging ability was remarkably decreased at pH1.2. It is assumed that reducing powers of seaweed extracts participated in their nitrite-scavenging abilities.