• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.606-613
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• 2010

In order to elucidate a mechanism responsible for the development of the odor characteristics of cooked, desirable-flavored shellfish, oysters were extracted using various solvents and the resulting extracts were evaluated organoleptically after cooking. The 80% aqueous methanol extract was found to produce a desirable cooked flavor. This oyster extract was fractionated using ion-exchange column chromatography and dialysis, and each of the fractions was subjected to cooking, followed by organoleptic evaluation. The outer dialysate fraction such as acidic and amphoteric water-soluble fractions produced a cooked oyster flavor. The volatile flavor compounds identified from cooked oyster included 29 hydrocarbons, 20 alcohols, 16 acids, 12 aldehydes, nine nitrogen-containing aromatic compounds, eight ketones, five furans, three esters, three phenols, and one benzene.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.118-126
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• 2021

The experiments to produce the vaterite type calcium carbonate were conducted for using the waste oyster shell as the recycling resources. Firstly, the oyster shell were calcinated at 800 ℃ for 24 h. Calcinated oyster shell were reacted with the nitric acid solution, and were diluted to 0.1 M Ca(NO3)2 solution. This solution was mixed with 0.1 M Na2CO3 contained 0.1 mol lysine/1 mol CaO at 20 ℃ and 600 rpm mixing condition for 1 h. The reaction products were identified to vaterite type calcium carbonate (84.5% vaterite, 15.5% calcite) by XRD and SEM analysis. Mean particle diameter was 6.87 ㎛, and the lysine content in calcium carbonate was analyzed to 0.1%.

• Journal of Biosystems Engineering
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• v.38 no.1
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• pp.41-47
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• 2013

Purpose: The objectives of this study were to construct the solar drying system with evacuated tubular solar collector and to investigate its performance in comparison with indoor and outdoor dryings. Methods: Solar drying system was constructed with using CPC (compound parabolic concentrator) evacuated tubular solar collector. Solar drying system is mainly composed of evacuated tubular solar collector with CPC reflector, storage tank, water-to-air heat exchanger, auxiliary heater, and drying chamber. Performance test of solar drying system was conducted with drying of agricultural products such as sliced radish, potato, carrot, and oyster mushroom. Drying characteristics of agricultural products in solar drying system were compared with those of indoor and outdoor ones. Results: Solar drying system showed considerable effect on reducing the half drying time for all drying samples. However, outdoor drying was more effective than indoor drying on shortening the half drying time for all of drying samples. Solar drying system and outdoor drying for oyster mushroom showed the same half drying time. Conclusions: Oyster mushroom could be dried easily under outdoor drying until MR (Moisture Ratio) was reached to about 0.2. However, solar drying system showed great effect on drying for most samples compared with indoor and outdoor dryings, when MR was less than 0.5.

• Journal of Animal Science and Technology
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• v.55 no.4
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• pp.273-280
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• 2013

This study was conducted to investigate the effects of fermented king oyster mushroom by-products diet (FMBD) on the growth performance, blood characteristics, and carcass traits of fattening pigs and its economics. The fermented diet mainly contained 40.0% king oyster mushroom (Pleurotus eryngii) by-products, 20.0% corn, 28.0% soybean meal, 0.1% supplemental probiotics and 0.08% cellulase. The mixed ingredients were fermented for 1 d at $37^{\circ}C$ followed by 9 d at room temperature, after which they were dried at $45^{\circ}C$ for 3 d. Pigs (n=96) were divided into eight heads per pen, four diet treatments and three replications. The basal diet (C) was substituted with 20% (T1), 50% (T2) and 80% (T3) FMBD. The concentration of crude protein (CP) was significantly higher (p<0.05) at the end of the fermentation period. The average daily gain (ADG) and feed efficiency were significantly lower (p<0.05) in T3 than C. Additionally, carcass grade was significantly better (p<0.05) in all treatments than C and the ratio of high carcass grade was higher. Although substitution of FMBD decreased growth performance, it improved carcass grade and decreased the feed cost of fattening pigs. Therefore, it was expected that the increase in the utilization ratio of FMBD will reduce the cost of animal production.

• Resources Recycling
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• v.16 no.3 s.77
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• pp.12-18
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• 2007

The material properties of waste oyster shell, which is largely generated from the treatment of marine products, have been investigated for its possible utilization as an adsorbent for fluoride ion-containing wastewater. The major composition of waste oyster shell was analyzed to be $CaCO_3$ and loss of 46% in weight reduction occurred during its thermal treatment by the emission of moisture and $CO_2$. The surface structure of oyster shell was decomposed by the heating and its surface potential was negatively increased with pH. As the pH of wastewater was increased, the adsorbed amount of fluoride ion onto oyster shell was decreased and the wastewater was found to be neutralized during adsorption process by ${CO_2}^{3-}$ which generated from the partial dissolution of oyster shell

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.890-893
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• 2001

Zeta potential measurement not only can provide surface information on colloidal biomaterials but more importantly can be used in bioprocess control and products quality control. In this study, zeta potentials for intracrystalline proteins of each layers from oyster shell prepared in 1mM NaCl at different pH were measured. Also, in forming calcite crystals with intracrystalline proteins as an additive extracted from oyster shell, the zeta potentials were measured. These studies were performed to verify the primary role of intracrystalline proteins in controlling the formation, morphological development and crystallography of the biocomposite.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.1
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• pp.9-15
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• 2006

As a part of the investigation for utilizing pearl oyster by-products, a rapid salt-fermented pearl oyster using commercial enzyme was prepared and also examined on the characteristics. The salt-fermented pearl oyster prepared by optimal condition, which was prepared by mixing of minced pearl oyster, 15% salt, and 1% $Protamex^\circledR$ and fermented for 4 weeks, was superior in hydrolysis degree (28.7%) and ACE inhibitory activity (92.6%) to salt-fermented pearl oyster prepared by other conditions, such as the use of whole tissue, different enzymes $(Alcalase^\circledR,\;Neutrase^\circledR\;and\;Flavourzyme^\circledR)$, different salt concentrations (20 and 25%), and different fermentation periods (2, 6 and 8 weeks). There were, however, some shortcomings with this product. It showed a dark green color and an unfavorable bitter taste. These shortcomings were improved by the addition of seasoning paste. The calcium and phosphorus contents of the seasoned salt-fermented pearl oyster were 64.2 mg/100 g and 71.6 mg/100 g, respectively, and the calcium content based on phosphorus was a good ratio for absorbing calcium. The total amino acid content of the seasoned and salt-fermented pearl oyster was 7,054 mg/100 g and the major amino acids ware aspartic acid (555.1 mg/100 g), glutamic acid (1,131.2 mg/100 g), alanine (658.2 mg/100 g), and lysine (695.5 mg/100 g). The seasoned salt-fermented pearl oyster, along with angiotensin I converting enzyme (ACE) inhibitory activity (98.3%), also showed a recognizable level (87.5%) of anti-oxidative activity.

• Korean Journal of Food Science and Technology
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• v.33 no.5
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• pp.534-539
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• 2001

To utilize oyster cannery processing waste water effectively, this study was carried out to prepare instant powdered soup using oyster wash water. Instant powdered soup from oyster hot-water extracts (HWE) was prepared by mixing oyster spray-dried hot-water extracts (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 instant powdered soup from oyster wash water (OWW), powder from oyster spray-dried wash water instead of the spray-dried hot water extracts, was added and other additives were added in proportion to those in the HWE. The OWW consists mainly of carbohydrates (71.1%). It was not different from the instant powdered soup from hot-water extracts. The volatile basic nitrogen, vaible cell counts, coliform group of instant powdered soup from oyster wash water contains 29.4 mg/100g, $4.6{\times}10^4\;CFU/g$, <18 MPN/100g, respectively and its water activity has 0.246. So it was a hygienically safe and conservable instant food. The main fatty acid of OWW was 16 : 0 and 18 : 1n-9. Its chemical score of protein was 59.4% and its main inorganic matter was iron. According to a sensory evaluation, in contrast to the HWE, the OWW had a slightly lower aroma but better taste. It was concluded from the above chemical and sensual evaluation that the oyster wash water can be used as a flavor enhancer for instant powdered soup.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.244-248
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• 2015

We explored the efficiency of natural antibacterial agents used to enhance the self-life and sensory properties of shucked and packed Pacific oyster Crassostrea gigas, which are in high demanded. First, we screened natural resources exhibiting antibacterial activity against food spoilage and pathogenic bacteria. Of theses, ignited oyster shell powder (IOS) and the natural food preservative, lactic acid bacteria fermented powder (LBF), were selected for further study considering the efficacy, mass production, and cost. The addition of 0.1% IOS (W/V) and 0.5% LBF (W/V) to shucked and packed oyster optimally extended the shelf-life without affecting the sensory evaluation. The results obtained in this study will provide a clue to enhance self-life in raw oyster products.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.335-342
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• 2017

Oysters Crassostrea gigas are a globally popular shellfish for human consumption. As filter-feeding bivalve mollusks, oysters may harbor many microorganisms and chemicals that could pose potential human health risks. The objective of this study was to investigate the suitability of cultured oysters for raw consumption or use in seafood products by measuring concentrations of harmful microorganisms and chemicals in their flesh. Microbial concentrations in cultured oysters were found to be: $1.0{\times}10^2-6.0{\times}10^4CFU/g$ (viable cell counts), not detected $(ND)-5.4{\times}10^3CFU/g$ (coliform bacteria), $ND-1.3{\times}10^2CFU/g$ (E. coli), and $ND-4.6{\times}10^3CFU/g$ (Vibrio parahaemolyticus). Other pathogenic bacteria, including Enterohemorrhagic E. coli (EHEC), Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp., were not detected in any samples. Heavy metal concentrations of cultured oysters were ND-0.239 mg/kg (total mercury), ND-1.091 mg/kg (lead), ND-0.968 mg/kg (cadmium). The concentrations of benzo(a)pyrene ranged from $0.280-0.880{\mu}g/kg$. Paralytic shellfish poison ranged from ND-0.58 mg/kg, while diarrhetic shellfish poison was not detected. No radioactivity was detected. These results suggest that oysters intended for raw consumption or use in seafood products should be subjected to chemical and biological controls.