• Mycobiology
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• v.37 no.1
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• pp.37-42
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• 2009

Comparative effects of oyster mushrooms on plasma and fecal lipid profiles and on liver and kidney function were evaluated in hyper and normocholesterolemic rats. Feeding of hypercholesterolemic rats a 5% powder of oyster mushrooms (Pleurotus ostreatus, P. sajor-caju and P. florida) reduced the plasma total cholesterol level by 37%, 21% and 16%, respectively and reduced the triglyceride level by 45%, 24% and 14%, respectively. LDL/HDL ratio decreased by 64%, 45% and 41% for P. sajor-caju, P. ostreatus and P. florida fed rats, respectively. Mushroom feeding also reduced body weight in hypercholesterolemic rats. However, it had no adverse effect on plasma bilirubin, creatinin and urea nitrogen level. Mushroom feeding also increased the total lipid and cholesterol excretion in the feces. The present study reveals that feeding of 5% oyster mushroom powder does not have detrimental effects on the liver and kidneys rather may provide health benefits for the cardiovascular-related complication by decreasing the atherogenic lipid profiles.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.3
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• pp.185-193
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• 2000

A water treatment agent with antimicrobial activity(Ag-Os) was created by exchanging silver ion($Ag^{+}$) on calcined oyster shell powder. The desorption of the exchanged silver ion was negligible, thereby indicating a stable antimicrobial water treatment agent. The sterilization effect of Ag-Os on underwater microorganisms was then investigated. An MIC (Minimum Inhibitory Concentration) test result indicated that Ag-Os had an excellent sterilization effect on G-germs, such as Escherichia coli and Pseudomonas aeruginosa. Most germs were annihilated with an Ag-Os concentration of 200 ppm and contact time of 60 minutes. The sterilization effect was mainly dependent on the contact time. The zeta potential of the Ag-Os powder adsorbed on sand was measured relative to the concentration of exchanged silver ion. As the concentration of the exchanged silver ion increased, the surface charge density of the anions on the surface of the Ag-Os powder adsorbed on sand also increased. Accordingly, this result indicated that a higher silver ion than ion exchange capacity was present on the particle surface due to adsorption. Consequently, this increased concentration of exchanged silver ion would appear to significantly enhance the sterilization power.

• Clean Technology
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• v.21 no.4
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• pp.241-247
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• 2015

Oyster shells are a waste product from mariculture that creates a major disposal problem in coastal regions of southeast Korea. To make practical use of unused oyster shells, calcined oyster shell (COS) collected from a local company was allowed to adsorb AITC (allyl isothiocyanate), and then tested the powder's ability to inhibit the growth of some potential food borne disease-causing bacteria. COS powder showed bacteriostatic effect that inhibited cell growth of Escherichia coli, Staphylococcus aureus and Salmonella typhimurium from 3 to 5 log10 CFU/mL at concentrations around 1%. The MIC of pure AITC was found as 1 mg/mL, 0.8 mg/mL and 0.7 mg/mL for Escherichia coli, Staphylococcus aureus and Salmonella typhimurium, respectively. The calcined powder adsorbed about 225 mg of AITC per gram of shell, indicating porous material was created by calcination. FTIR data confirmed the adsorption of AITC by COS. Characterization of particle data showed very fine particle size and highly convoluted surface. AITC adsorbed calcined oyster shell (ACOS) completely inhibited bacterial cell at 1% concentration. ACOS showed better antibacterial effect than COS, indicating synergistic effect of AITC and calcined oyster shell powder on bacteria.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_2
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• pp.79-88
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• 2001

Humic acids react with chlorine to produce Trihalomethanes(THMs), known as carcinogens, during disinfection, the last stage in water purification. Currently, the removal of organic humic acids is considered the best approach to solve the problem of THM formation. Accordingly, the current study examined the adsorption of organic compounds of humic acids onto an inorganic carrier prepared from oyster shell waste. The adsorbent used was activated oyster shell powder(HAP) and silver ion-exchanged oyster shell powder(HAP-Ag), with CaCO$_3$ as the control. The adsorbates were phthalic acid, chelidamic acid, catechol, dodecylpyridinium chloride(DP), and 2-ethyl phenol(2-EP). The adsorption experiments were carried out in a batch shaker at $25^{\circ}C$ for 15 hours. The equilibrium concentration of the adsorbate solution was analyzed using a UV spectrophotometer and the data fitted to the Langmuir isotherm model. Since the solution pH values were found to be greater than the pKa values of the organic compounds used as adsorbates, the compounds apparently existed in ionic form. The adsorptive affinities of the organic acid and phenolic compounds varied depending on the interaction of electrostatic forces, ion exchange, and chelation. More carboxylic acids and catechol, rather than DP and 2-EP, were adsorbed onto HAP and HAP-Ag. HAP and HAP-Ag exhibited a greater adsorptive affinity for the organic compounds than CaCO$_3$, used as the control.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.224-229
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• 2001

This study was carried out to examine the quality stability of powdered soup using powder from oyster wash water (PSW). To compare the quality stability, powdered soup from oyster hot-water extracts (PSE) was also prepared by mixing hot-water extract powder (15 g), 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 PSW, powder from oyster wash water, instead of powder from oyster hot-water extracts, was added and other additives were the same proportion as PSE. The PSW and PSE were packed with laminated film bag (OPP,$20\;{\mu}m$; PE, $20{\mu}m$; paper, $45\;g/m^3$; PE, $20\;{\mu}m$; Al, $7\;{\mu}m$; PE, $20\;{\mu}m$), and then stored at ambient temperature for 12 months. The moisture content, water activity, peroxide value, and fatty acid composition showed little changes during storage of the PSW, The pH, volatile basic nitrogen content, and brown pigment formation increased slightly, while white index decreased slightly during storage of PSW. No significant difference was observed in the changes of food components between PSW and PSE during storage. According to a sensory evaluation, the change in quality of PSW was negligible during 12 months of storage. From the results of the chemical experiment and sensory evaluation, PSW packed with laminated film bag (OPP, $20\;{\mu}m$; PE, $20\;{\mu}m$; paper, $45\;g/{\mu}m$; PE, $20\;{\mu}m$) was revealed to be preserved in good quality during 12 months of storage.

• Environmental Engineering Research
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• v.25 no.2
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• pp.230-237
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• 2020

Nitrogen flux release from organically enriched sediments into overlying water, which may have significantly influence on water quality and increasing continuous eutrophication. The purpose of this study is to evaluate the remediation efficiency of oyster shell powder and its treated product into organically enriched sediment in terms of nitrogen flux, organic matter, chlorophyll-a, pH and dissolved oxygen (DO). The TOSP was mainly composed of CaO2. The application of TOSP into the sediment has increased the pH, DO and significantly decreased the concentrations of NH₄⁺-N and T-N compared to other basins. On the other hand, nitrate was enriched with the addition of treated oyster powder, an oxygen releasing compound on both phases. Furthermore, chlorophyll-a was found to be increasing with time in the control basin meanwhile it dropped drastically with the addition of TOSP, which implied on the repression of algal growth owing to blockage of nitrogen source migrating from the sediment. This study has shown that the TOSP was effective to improve sediment-water quality, diminish eutrophication and control harmful algae blooms in a marine environment. Therefore, it is a good reference as an effective environmental remediation agent.

• Resources Recycling
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• v.11 no.2
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• pp.45-51
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• 2002

This study was performed to investigate removal efficiency of wastewater by the prepared coagulant using waste oyster shell and loess. Waste oyster shell and loess contain respectively high CaO(55.43% by weight), $SiO_2$(45.30% by weight). Waste oyster shell was calcined to improve the purity of CaO at the calcination condition of $900^{\circ}C$ for 2hours, and then crushed 0.074 mm(200mesh) size by ball mill. Also, coagulant was prepared with calcined waste oyster shell and loess powder by hydration reaction. Calcined waste oyster shell and loess powder were combined with mixing ratio of 6 : 4, 7:3, 8:2 and 9:1. Though comparison experiment between prepared coagulant and chemical )$Ca(OH_2$, prepared coagulant was proved as having replaceable possibility of chemical )$Ca(OH_2$in wastewater treatment plant.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.46-47
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• 2020

Oyster shells and egg shells consist of CaCO3, which is known to have excellent fire performance as the main component, and research is currently being conducted as a fireproof board material. Therefore, in this study, the physical and chemical properties of oyster shell powder and egg shell powder are studied to find out the applicability of fireproof board

• Food Science of Animal Resources
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• v.38 no.6
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• pp.1179-1188
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• 2018

This study aimed to investigate the combined effect of using natural calcium mixtures and various binding ingredients as replacers for synthetic phosphate in ground pork products. We performed seven treatments: control (0.3% phosphate blend), treatment 1 (0.5% natural calcium mixtures [NCM, which comprised 0.2% oyster shell calcium and 0.3% egg shell calcium powder] and 0.25% egg white powder), treatment 2 (0.5% NCM and 0.25% whey protein concentrate), treatment 3 (0.5% NCM and 0.25% concentrated soybean protein), treatment 4 (0.5% NCM and 0.25% isolated soybean protein), treatment 5 (0.5% NCM and 0.25% carrageenan), and treatment 6 (0.5% NCM and 0.25% collagen powder). All the treatment mixtures had higher pH and lower cooking loss than the control, which was treated with phosphate. We found that NCM and binding ingredients had no negative effects on the moisture content, lightness, and yellowness of the cooked ground pork products. Treatments 3 and 4 showed significantly lower CIE $a^*$ values than the control. Treatments 2 and 6 improved the textural properties of the products. In conclusion, the combination of NCM with whey protein concentrate or collagen powder could be suitable for producing phosphate-free meat products.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.154-155
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• 2016

Oyster shell is light weighted and its strength characteristic is similar to sand. So we produced mortar test piece using grounded oyster shell powder under 0.5mm, which is a standard of fine aggregate, and reviewed strength properties according to water cement ratio. In our test, we used two kinds of oyster shell particles: below 0.6mm and 1.2~2.5mm. Water cement ratio is varied 40% to 100% and we found that flexural strength and compressive strength are decreased in higher water cement ratio.