• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.777-787
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• 2017

Organic enrichment and pollution was investigated in surface sediments from Jinhae Bay and Geoje-Hansan Bay of Korea, which contain the largest oyster farms in Korean coastal areas. Geochemical indicators (chemical oxygen demand, total organic carbon, ignition loss, and acid volatile sulfide) in sediments, ammonium and nitrate in pore water, and bioluminescence inhibition test for sediment extracts were analyzed. Temporal changes of organic enrichment were also investigated using sediment core samples from Geoje-Hansan Bay. The level of organic pollution in sediments from Jinhae Bay was significantly greater than that of sediments from Geoje-Hansan Bay. Compared with other sites, Jinhae Bay was one of the most polluted coastal areas of Korea. The levels of geochemical indicators in May were comparable to, or higher than, in August. Ammonium concentrations in pore water were two orders of magnitudes greater than the nitrate concentrations, suggesting that the bays are reducing environments. The concentrations of total organic carbon in core sediment samples from shellfish-farming areas increased significantly from 2000 to the present year, and it seems to be associated with increases in anthropogenic activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.829-833
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• 2012

To investigate the effects of oyster mushrooms (Pleurotus ostreatus) on beef and pork tenderization, freezedried mushroom (whole, cap, and stem) powder and mushroom extracts were prepared. Both fresh and boiled beef and pork had mushroom power and extract powders spread on them, and let sit for 30 minutes at room temperature. After that, the hardness and amino nitrogen content of the meats were measured. The hardness of the meat decreased by about 20%~35% after spreading. Also, the amino nitrogen contents increased due to the effect of protease in the mushrooms. The effects were greater in raw beef. The mushrooms showed almost the same effects regardless of which part of the mushrooms were used (whole, cap, and stem).

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.1018-1023
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• 2005

Simplified procedure was developed for concentrating and detecting poliovirus and norovirus in oysters. Viruses were seeded into oyster tissue homogenates and concentrated through polyethylene glycol (PEG) precipitation, chloroform or Freon extraction, with additional PEG precipitation. Amount of viruses was evaluated using poliovirus plaque assay. Virus recovery during concentration procedure was approximately 16.4-26.0%. For defection, viral RNAs in oysters were examined using one-step RT-PCR after extraction with Trizol. Dilution or capturing of viral RNA using silica gel membrane allowed viruses to be detected by RT-PCR, whereas viruses could not be removed using $QIAshredder^{TM}$ Homogenizer, which is effective in removing RT-PCR inhibitors in lettuce and hamburgers. Freon extraction, generally used to concentrate viruses found in food, could be substituted with chloroform extraction using this procedure; no difference could be observed between detection limits of whole oyster extracts and digestive organ extracts indicating that RT-PCR inhibitors were distributed evenly throughout whole tissues. Nested PCR greatly improved efficiency of this procedure. Overall, this procedure could remove sufficient amount of inhibitors to allow detection of norovirus in oysters.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.3
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• pp.285-290
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• 2001

To utilize canned oyster processing waste water effectively, this study was carried out to prepare instant powdered soup using the waste water (IPSW), Instant powdered souu from oyster hot-water extracts (IPSE) was prepared by mixing hot-water extracts powder (15 g) with table salt (5 g), cream powder (19 g), milk replacer (12 g), wheat flour (20 g), corn flour (15 g), starch (5 g), glucose (7.5 g) and onion powder (1.5 g). In preparing IPSW, mixed powder from wash water and boiling liquid waste, instead of powder from hot-water extracts and table salt, was added (powder from boiling liquid waste: powder from wash water= 12: 8) and other additives were added in proportion to those in the IPSE, The IPSW consists mainly of carbohydrates (about $72\%$). It was not different from the IPSE. The volatile basic nitrogen, viable cell counts, coliform group of the IPSW contains 33.4 mg/100g, $2.2\times10^4CFU/g$, <180 MPN/100g, respectively, and its water activity has 0.257. So it was a hygienically safe and conservable instant food. The main fatty acids of IPSW were 16: 0 and 18: 1n-9. Its chemical score of protein was $61.4\%$ and its main inorganic matter was iron. According to a sensual evaluation, in contrast to the IPSE, the IPSW had a bit lower aroma but better taste, It was concluded from the above chemical and sensory evaluation that even the boiling liquid waste which had been mostly abandoned because of its high table salt content can be used as a good material for instant powdered soup if it's powdered and mixed adequately with powder from wash water, and its table salt content is properly adjusted.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.2
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• pp.211-216
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• 2009

This study was conducted to determine whether Pleurotus ostreatus (oyster mushroom), cultivated in various ratios with herbal extract remnants instead of cotton supplemented with nutrients (the control), improved mycelial growth, mushroom yields and longevity during storage. In addition, we investigated the transfer of medicinal herb components into the mushrooms since they contained non-specific medicinal herbs and their composition could not be controlled. Mushrooms cultivated with 70% and 100% medicinal herb remnants had faster growth rates, higher yields and less failure in the development of the fruit body than the control group. There were no differences in HPLC chromatogram among the methanol extracts of Pleurotus ostreatus in all groups. In addition, glycyrrhizin, an indicative compound of licorice which was a major herb among the herbal remnants, was not detected in any of the extracts. Pleurotus ostreatus that was cultivated with 70% and 100% herbal extract remnants had improved storage longevity in comparison with the control. They exhibited the least weight loss during storage among the groups and they maintained firmness in the stipe and pileus. However, the sources of media did not alter the color difference of the stipe and pileus or the quality index of the outward appearance during storage. In conclusion, cultivating media that contained over 70% of medicinal herb extract remnants increased the growth rates and yields of Pleurotus ostreatus. In addition, these mushrooms had enhanced storage longevity due to their firmness. Therefore, medicinal herb extract remnants should be utilized in the cultivating media of various mushrooms.

• Mycobiology
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• v.41 no.4
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• pp.214-220
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• 2013

This study was conducted in order to perform efficient extraction of lignocellulolytic enzymes amylase (EC 3.2.1.1), cellulase (EC 3.2.1.4), laccase (EC 1.10.3.2), and xylanase (EC 3.2.1.8) from spent mushroom compost (SMC) of Pleurotus ostreatus, P. eryngii, and P. cornucopiae. Optimal enzyme recovery was achieved when SMCs were extracted with 50 mM sodium citrate (pH 4.5) buffer at $4^{\circ}C$ for 2 hr. Amylase, cellulase, and xylanase activities showed high values in extracts from P. ostreatus SMC, with 2.97 U/g, 1.67 U/g, and 91.56 U/g, respectively, whereas laccase activity and filter paper degradation ability were highest in extracts from P. eryngii SMC, with values of 9.01 U/g and 0.21 U/g, respectively. Enzymatic activities varied according to the SMCs released from different mushroom farms. The synthetic dyes remazol brilliant blue R and Congo red were decolorized completely by the SMC extract of P. eryngii within 120 min, and the decolorization ability of the extract was comparable to that of 0.3 U of commercial laccase. In addition, laccase activity of the SMC extract from P. eryngii was compared to that of commercial enzymes or its industrial application in decolorization.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.289-294
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• 2001

Yields of shells, appearance of the shellfishes, mineral contents of the shells and their hot water extracts were determined in six shellfishes such as corb shell(CS). short neck clam(SNC). taste clam(TC), ark shell(AS). top shell(TS) and oyster(OY) from the western coast of Korea. Yields of shells in shellfishes were 70.I~80.5% but yields of TC was the lowest as 40.7%. The highest among weight of the shell the shellfishes was the TS(26.2g) and the lowest weight was TC(5.6g) Colors of CS, SNC, TC. AS. TS and OY were yellowish brown, brown, black. greenish brown and gray. respectively. Ca content of the shell of shellfishes was 36.23~38.78% and the content of K and Na were 0.23~4.54% and 1.48~l.59%, respectively. Contents of Na, Mg, Fe. Mn, Zn, Cu. P and S were in the range of 0.01~0.21%. It also contained heavy metals, such as Pb(1.90~7.75 ppm), Cd(0.5~4.50 ppm), As (1.40~4.30 ppm), Se (0.2~l.50 ppm). Cr(1.00~8.30 ppm) and Hg(0.002~8.2 ppm), Ca content in hot water extracts of shell of shellfish was the highest in TC(2,448 mg/100 g), and the lowest in SNC(115 mg/100 g). K content in TC extracts was the highest with the levels of 952 mg/100 g. P content of TC and SNC were 201 and 0.36 mg/100 g, respectively. The contents of Pb, As, Se and Cr were the highest in the extracts of TC and were 110. 40. 90, 20 $\mu$g/100 g, respectively. But Cd was not detected in the extracts of SNC.

• Journal of Food Hygiene and Safety
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• v.31 no.2
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• pp.119-125
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• 2016

Antioxidative components and activities of the extracts from Pleurotus ostreatus extracted at different ethanol concentration were analyzed and their correlation were investigated. Ergothioneine, total phenolic compounds, and flavonoid contents of the extracts from P. ostreatus extracted with hot water (0% ethanol) were the highest ($2.98{\pm}0.05$, $9.51{\pm}0.45$, and $2.83{\pm}0.03mg/g$, respectively) and the contents were decreased according to increase of ethanol concentration for extraction. DPPH and ABTS radical scavenging activities of the extracts from P. ostreatus extracted with hot water were the highest ($80.41{\pm}0.56$ and $91.47{\pm}0.11%$, respectively). FRAP value also showed the highest reducing power by $8.86{\pm}0.33\;FeSO_4\;eq$. mM in hot water extracts. Positive correlations were found between ergothioneine contents and antioxidative active components and antioxidant activity of the extracts from P. ostreatus. Results indicate that hot water extraction was most efficient for the extracts with high antioxidative activities from P. ostreatus.

• Journal of fish pathology
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• v.24 no.2
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• pp.65-73
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• 2011

In analysis of DNA viruses from the contaminated shellfish using PCR, preparation method of template DNA is an important factor to get enough copy number of viruses. In this study, we evaluated the efficiency of PCR template of Megalocytivirus (sT50mg-D) DNA obtained from 50 mg digestive gland homogenate of oyster using commercial method, and compared with that obtained from 5 g of the same tissues (T5g-D) after PEG precipitation procedures of virus. Both templates DNA suspended in the same volume of distilled water showed positive results by primary PCR with 35 cycles, and the presence of Megalocytivirus was confirmed in oysters collected from cultured farms in Korea. Moreover, PCR with sT50mg-D allowed us to discriminate the contaminated oyster individually, that can not be done in PCR with T5g-D prepared from the mixture of three different individual oyster to get 5 g digestive gland homogenate. In quantitative analysis with real time PCR, Megalocytivirus concentrations in 50 ${\mu}l$ templates prepared using 0.5~50 mg of one positive sample were appeared in the range 6.14E+00~1.2E+02/${\mu}l$. We were not able to get positive result using template DNA contained less than 6.14E+00 copies. Consequently, 2-step PCR performed with DNA extracts from oyster homogenate of small amount (sT50mg-D) i) was enough to detect the contaminated Megalocytivirus in shellfish, ii) allowed us to do the analysis for individual shellfish rather than mixture of several shellfish and iii) showed the presence of Megalocytivirus in oyster from Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.321-326
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• 1986

Oyster (Crassostrea gigas), arkshell (Anadare(Scapharce) broughtonii) and sea-mussel (Mytilus edulis) were investigated as to their lipid classes. Lipid extracts from shellfishes were fractionated into neutral lipid (NL), glycolipid (GL) and phospho-lipid (PL) by column chromatography with silicic acid. The fatty acid compositions of their lipid classes and lipid fractions were determined by gas liquid chromatography (GLC). Total lipid contents of shellfishes were $3.5\%$ in the oyster, $1.4\%$ in the arkshell, $1.0\%$ in the sea-mussel. The major fatty acids of total lipids were palmitic acid, eicosapentaenoic acid and docosahexaenoic acid in the oyster and the sea-mussel, palmitic acid, oleic acid and eicosapentaenoic acid in the arkshell. The lipid composition of neutral lipid fractions in shellfishes was separated and identified as free sterol, free fatty acid, triglyceride, hydrocarbon and esterified sterol by TLC. Of these classes, triglyceride fraction was most abundant, amounting to 55.6, 77.7 and $60.4\%$ in the three samples mentioned above, respectively. The main fatty acids of glycolipid were palmitic acid, eicosaenoic acid and docosahexaenoic acid in oyster, myristic acid, palmitic acid and palmitoleic acid in the arkshell, docosahexaenoic acid, linolenic acid and palmitic acid in the sea-mussel. The major fatty acids of phospholipid were palmitic acid, eicosapentaenoic acid and docosahexaenoic acid in the oyster and sea-mussel, palmitic acid, eicosapentaenoic acid and erucic acid in the arkshell.