• Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.113-121
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• 1999

Changes in lipid content, lipid class and fatty acid compositions of the cultured oysters in shallow-water, Bukman bay (Tongyeong, Korea), using both Korean and Japanese spats were investigated. The content of non-polar lipid (NL) comprised approximately $60- 80\%$ of total lipid (TL) in the cultured oysters. There was a positive correlation between NL content and meat weight, y=0.287lx-15.309 (r=0.834l, p<0.001). The prominent fatty acids of the oysters were 16:0, 20:5n-3 (eicosapentaenoic acid, EPA), 22:6n-3 (docosahexaenoic acid, DHA), 18:0, l8:1n-7, l8:1n-9, l6:1n-7, 14:0 and l6:4n-3. During the growth of the oysters, l6:4n-3 showed the highest coefficient of variation, accounting for $41.8\%$ for the Korean oyster and $32.3\%$ for the Japanese one, respectively. Both oysters showed low level of n-3 fatty acids such as DHA and EPA and high level of n-6 fatty acid, 20:4n-6, in the spawning period (August). During growth of the oysters, both EPA and DHA were the richest fatty acids in the harvest period (December, 314 mg/100g sample) and in the pre-spawning period (July, 237-247 mg/100g sample), respectively. Consequently, the cultured oyster with Japanese spat contained approximately two times more n-3 fatty acids per oyster individual than those with Korean one in the harvest season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.3
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• pp.269-277
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• 2006

This study prepared functional oyster hydrolysates using two-step enzymatic hydrolysis and investigated their functional properties. To prepare two-step enzymatic hydrolysates (TSEH), oysters were hydrolyzed using 1% Protamex (PR) at $40^{\circ}C$ and pH 6.0 for 1 hr before sequential treatment with one of the following enzymes for 1 hr: Alcalase (AL), Flavourzyme (FL), Neutrase (NE), pepsin (PE), and trypsin (TR). The PRAL, PRNE and PRTR hydrolysates had significantly greater angiotensin I converting enzyme (ACE) inhibitory activity than did PR and the other TSEHs. Only the antioxidant activity of the PRNE hydrolysate was significantly different (p<0.05), while none of the TSEHs had antimicrobial activity. The oyster hydrolysate prepared by sequential treatment with Protamex and Neutrase (PRNE) had the best ACE inhibitory activity and antioxidant activity, with $IC_{50}$ values of 0.40 and 0.94 mg/mL, respectively. The PRNE hydrolysate was processed through an ultrafiltration (UF) series with molecular weight cut-off (MWCO) membranes of 3, 5, 10, and 30 kDa, and the ACE inhibitory, antioxidant, and antimicrobial activities of the permeates were determined. The permeate through the 3-kDa MWCO membrane had greater ACE inhibitory activity and antioxidant activity than did the other PRNE permeates, with $IC_{50}$ values of 0.11 and 0.40 mg/mL, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.4 s.107
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• pp.60-66
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• 2004

In this paper, oyster shell, diatomaceous earth, and active carbon were used as filter media for treating wastewater produced in paper mills. After filtering, the changes of COD and turbidity were investigated. As the results of estimating the efficiency of wasterwater treatment, porous oyster shell having higher specific surface area in powder was more effective than the others in removal of contaminants in waterwater, especially turbidity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.434-444
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• 2021

The decrease in fatness of the Pacific oyster Crassostrea gigas, which consequently results in decrease in the profit of aquaculture industry, has become a source of serious concern in southeast coast of Korea. The ratio of flesh (edible portion) to total oyster weight, commonly called edible portion yield ("suyul" in Korean), have been used as a fatness index for the healthy and valuable state of oyster from the early stage of oyster farming in Korea. More than 360 data sets were collected from early culturing periods (in the 1970s) to the present from approximately 15 published literatures to evaluate the long-term fatness trend of oyster, reared particularly in submerged longline culturing system in Gyeongsangnam-do province. Slight decrease in oyster fatness during the 1970s to 1990s was detected in Tongyeong and Geoje Bays; however, from the 1990s to the present, clear decreasing trends were observed with a decrease of 0.04-0.08% year^-1, especially during harvest season. Oyster mass production per unit area almost doubled within a short period in the early 2000s; however, changes in coastal environment factors inhibited the fattening of shellfish from the mid 1990s. These results indicate that the severe competition in feeding and low biological production in water column might be some convincing reasons for the decrease in fatness of oyster from the 1990s, in Tongyeong and Geoje Bays, Korea.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_2
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• pp.1135-1144
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• 2023

In this paper, bending strength and permeability tests were conducted on concrete permeable blocks manufactured by recycling industrial by-products of oyster shell and blast furnace slag to measure and compare bending strength and permeability coefficient, and present experimental research results. To this end, a total of 54 specimens with a size of 200x200x60mm for surface layer and base layer were manufactured, and bending strength and permeability test were carried ourt accoridng to KS F 4419. Eighteen types of mixing designs were implemented by varying the mixing and replacement rates of oyster shells and blast furnace slag. As a result of the experiment, the higher the mixing ratio of oyster shell, the lower the bending strength and the permeability coefficient. Thereafter, a total of three permeable blocks with dimensions of 200x200x60mm were manufactured and subjected to bending strength and permeability tests according to KS F 4419. As a result of the test, the bending strength satisfies the standard of KS F 4419, and the permeability coefficient is 12 times higher than the standard of KS F 4419. It seems that the proper mixing of oyster shells and blast furnace slag increases the amount of air, and further research on durability and economic feasibility of materials used to manufacture permeable blocks is required.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.156-164
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• 2020

To develop a seasoned laver from cooking oyster effluent (C-COE), this study optimized the C-COE concentration, roasting temperature and time using response surface methodology (RSM). The optimal C-COE concentration, roasting temperature and time for producing seasoned laver from C-COE were 31.0%, 182.2℃ and 21.1 sec, respectively. The proximate composition of the seasoned laver prepared with C-COE under the conditions was 5.2% moisture, 37.4% crude protein, 8.2% crude lipid, 11.1% ash, 38.1% carbohydrate. The water activity of the prototype seasoned laver was 0.038. The prototype had stronger taste and flavor intensities than a commercial product. There was no difference (P>0.05) in the Hunter color value between the prototype and the commercial product. The peroxide (POV) and acid values (AV) of the prototype were 6.0 meq/kg and 1.4 mg KOH/g, respectively, which are considered acceptable. The results suggest that the seasoned laver with C-COE developed can be industrialized.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1484-1490
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• 2006

This study was carried out to prepare spaghetti sauce with adductor muscle of pearl oyster (SSAM) and to compare with commercial spaghetti sauce (CSS). From the results of organic acid, pH, hunter color value and sensory evaluation, the optimal addition ratio of adductor muscle of pearl oyster was 11% based for preparing SSAM and reasonable $F_0$ value was about 4 min for keeping storage of SSAM. The proximate composition of SSAM was 69.8% for moisture, 3.7% for protein, 4.2% for crude lipid and 3.4% for crude ash. SSAM was superior in sensory flavor and texture to CSS. There was, however, no significant difference (p<0.05) in sensory color between CSS and SSAM. The total amino acid content (3,033.4 mg/100 g) of SSAM was higher than that (2,305.7 mg/100 g) of CSS and the major amino acids were aspartic acid, glutamic acid, leucine and lysine. Calcium and phosphorus contents in SSAM were 48.5 mg/100 g and 27.1 mg/100 g, respectively. Calcium level based on phosphorous was 1.78, which was a good ratio for absorbing calcium. The free amino acid content and taste value of SSAM were 989.4 mg/100 g and 141.04 mg/100 g, respectively These results suggested that the major taste active compounds among free amino acid were glutamic acid and aspartic acid.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.2
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• pp.120-129
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• 2017

This study assessed the safety of raw oysters Crassostrea gigas for consumption during processing in a processing plant. Bacterial contamination (e.g., viable cell counts, coliform groups, Escherichia. coli and pathogenic bacteria) and chemical contamination (e.g., heavy metals and shellfish toxins) were measured on raw oysters, a processing equipment, employees and work areas. No total mercury, lead, paralytic shellfish poison, diarrheic shellfish poison or norovirus was detected in any post-harvested oyster samples. However, the cadmium level ranged from 0.1-0.2 mg/kg. The viable cell count, E. coli and coliform group levels in post-harvested oysters ranged from 4.00-4.54 log CFU/g, ND-210 MPN/100 g and 110-410 MPN/100 g, respectively. The viable contaminating cell counts on employees, equipment and work areas were in the range of $0.90-3.46log\;CFU/100cm^2$. Airborne bacteria in the work areas ranged from 0.60 to 1.81 log CFU/plate/15 min. Thus, no significant health risks were detected in the processing plant.

• Journal of Energy Engineering
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• v.27 no.1
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• pp.76-80
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• 2018

The objective of this research paper is to discuss the waste coffee residue disposal and its environmental effects on the environment. As we know, coffee is one of the most demand and swallowed beverages in the world, which leads to large quantities of solid waste. Which can be toxic and a lot of environmental problems occur. In developing countries, there is a lack of proper coffee waste residue management. The coffee beans and residues contain several organic compounds. The wastewater from coffee industry emitted several pollutants (highly concentrated) and it contaminates the soil, ground waters, aquatic life, and also human health. Hence it is essential to treat the coffee waste residues. Mean while, oyster shell waste and its disposal also a big environmental challenge in the coastal regions of southeast Korea. In this paper, we focused the treatment of coffee waste residue with oyster shell waste powder. Primarily, oyster shells are calcinated at higher temperatures and investigated the calcined CaO powder as an anti microbic agent to the bacteria presented in coffee waste residues. We successfully applied calcium oxide from oyster shell waste, as an antimicrobic agent.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.4
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• pp.464-469
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• 2006

This study was conducted to evaluate a knowledge on food components of muscle and adductor muscle of pearl oyster (Pinctada fucata martensii) as pearl processing byproducts. The concentrations of mercury and chromium as heavy metal were not detected in both pearl oyster muscle and adductor muscle, and those of cadmium and lead were 0.06 ppm and 0.11 ppm in only pearl oyster muscle, respectively. Thus, the heavy metal levels of pearl processing byproducts were below the reported safety limits. The volatile basic nitrogen (VBN) content and pH of pearl oyster muscle were 11.6 mg/100g and 6.31 and those of abductor muscle were 8.6 mg/100 g and 6.33, respectively. It was concluded that pearl oyster muscle and adductor muscle might not invoke health risk in using food resource. The contents of crude protein (16.5%) and total amino acid (15,691 mg/100 g) of adductor muscle were higher than those of muscle (11.2% and 10,131 mg/100 g) and oyster (12.1% and 11,213 mg/100 g) as a control. The contents of calcium and phosphorus were 95.4 mg/100 g and 116.0 mg/100 g in muscle, 75.2 mg/100g and 148.1 mg/100 g in adductor muscle, respectively. The calcium level based on phosphorus was a good ratio for absorbing calcium. The free amino acid contents and taste values were 635.5 mg/100 g and 40.2 in muscle, and 734.9 mg/100 g and 24.1 in adductor muscle, respectively, but that (882.8 mg/100 g and 40.2) of oyster was higher than those of pearl processing byproducts. Based on the results of physicochemical and nutritional properties, pearl oyster muscle and adductor muscle can be utilized as a food resource.