• Fisheries and Aquatic Sciences
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• 제12권1호
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• pp.6-15
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• 2009

Biochemical and functional properties of acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) from rockfish skin were characterized. Yield of PSC (90.0%) was higher than that of ASC (63.2%). Both ASC and the PSC consisted of ${\alpha}1$ and ${\alpha}2$ chains, and $\alpha$-cross-linked components. According to the results of hydroxylation of proline and lysine, and FT-IR, no difference between the helical structure of ASC and PSC was identified. Thermal denaturation temperature (TDT) of ASC from rockfish skin was $22.8^{\circ}C$, the same as exhibited in PSC. Both ASC and PSC were higher in water absorption capacity (WAC) and oil absorption capacity (OAC) than other vegetable proteins. According to the results of emulsifying activity (EA) and cooking stability (CS), both ASC and PSC from rockfish skin were inferior compared to the commercial emulsifier (Tween-80). The results of FT-IR suggested that the structure of PSC was slightly different when compared to that of ASC. No differences in solubility were established between ASC and PSC from rockfish skin at various pH and NaCl concentrations.

• 한국어병학회지
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• 제21권3호
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• pp.247-257
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• 2008

To understand the activity of non-specific defence factors in cultured Sebastes, the antibacterial effect of the serum, skin mucus and homogenate of various organs from cultured oblong rockfish (Sebastes oblongus) and rockfish(Sebastes schlegeli) against pathogenic bacteria, Aeromonas hydrophila, Edwardsiella tarda, Vibrio anguillarum, and Streptococcus sp. was compared with that of flounder(Paralichthys olivaceus) and seabass(Leteolabrax japonicus). And the activities of proteolytic enzyme, chitinolytic enzyme and haemolycin as non-specific defence factor were investigated on the oblong rockfish and rockfish. Samples from oblong rockfish showed the highest antibacterial activity by lysoplate assay on agar plate mixed with pathogens, followed in descending order by rockfish, seabass, and flounder. Turbidimetric assay was carried to evaluate the lysozyme activity of fish samples against lyophilized cells of Micrococcus lysodeiktikus. The serum, kidney, liver, stomach, intestine and eyeball of oblong rockfish and the mucus and gill of rockfish appeared to have the highest lysozyme activity among the fish strains investigated. All samples except skin mucus, liver, and eyeball of oblong rockfish and rockfish showed proteolytic enzyme activity. Chitinolytic enzyme activity was showed in random sampling and haemolytic activity was remarkable in oblong rockfish. Therefore, Sebastes strain was proved to have effective defense mechanisms based on the antibacterial activities, and lysozyme, proteolytic enzyme, chitinolytic enzyme, and haemolycin were considered to act as the non-specific defence factor of Sebastes.

• Fisheries and Aquatic Sciences
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• 제13권1호
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• pp.1-11
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• 2010

The study was performed to optimize the processing conditions (alkali concentration, extraction time, and temperature) for rockfish skin gelatin based on yield using response surface methodology and comparison of the physicochemical properties with those of rockfish skin gelatin pretreated and extracted under ordinary conditions (alkali treatment concentration: 1.0 M; extraction time: 2 hr; extraction temperature: $60^{\circ}C$). Predicted maximum gelatin yield of 19.1% and gelatin content of 87.8% were obtained by extraction at $106.6^{\circ}C$ for 69.0 min after pretreatment with 1.1 M calcium hydroxide. Yield of gelatin extracted under high temperature/high pressure (G-HT/HP) was 54% higher than that extracted under ordinary temperature/time (G-OT/T). However, G-HT/HP was inferior in gel strength and gelling point to (G-OT/T), but comparable in transmission. Based on the physicochemical properties, G-HT/HP was unsuitable for use in products requiring higher physical properties, but could be useful for health-functional foods.

• Fisheries and Aquatic Sciences
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• 제14권1호
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• pp.1-10
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• 2011

This study was conducted to obtain hydrolysates with potent antioxidative activity from rockfish skin gelatin. Gelatin was extracted under high temperature/high pressure using a two-step enzymatic hydrolysis with commercial enzymes such as Alcalase, Flavourzyme, Neutrase, and Protamex. The second rockfish-skin gelatin hydrolysate (SRSGH) was prepared by further incubating the first gelatin hydrolysate (FRSGH), which had been hydrolyzed with Alcalase for 1-h (FRSGH-A1), with Flavourzyme for 2-h (SRSGH-F2). The second gelatin hydrolysate showed higher antioxidative activity of 3.72 as measured by a Metrohm Rancimat and superior angiotensin I-converting enzyme (ACE) inhibiting activity of 0.82 mg/mL. Compared with the gelatin, the relative proportion in SRSGH-F2 was markedly decreased in the 100-kDa peak, whereas it was increased in that less than 100-kDa. The amino acid composition of SRSGH-F2 was rich in glycine (25.9%), proline (10.8%), alanine (9.1%), and glutamic acid (9.1%). In contrast, it was poor in cystine (not detected), methionine (1.6%), tyrosine (0.4%), hydroxylysine (0.9%), and histidine (0.9%). In recent years, demand for natural functional foods has been increasing, and SRSGH-F2 can be used as a functional food ingredient in the food industries. However, further detailed studies on SRSGH-F2 with regard to its antioxidant activity in vivo and the various antioxidant mechanisms are needed.

• 한국수산과학회지
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• 제47권5호
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• pp.603-610
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• 2014

We investigated a nematode infection in the epithelial tissue of rockfish Sebastes schlegeli cultured in Cheonsu Bay, western Korea, from May 2013 to April 2014. Nematodes infected the epithelial tissues of various external organs, including the fins, operculum, nares, mouth, and head. Over a 1-year period, the overall nematode infection rate in rockfish was 55% (n=89/163): 56.7% (n=17/30) in May 2013, 88% (n=29/33) in August 2013, 0% (n=0/30) in October 2013, 70% (n=21/30) in January 2014, and 55% (n=22/40) in April 2014. During this study, the only mass mortality of cultured rockfish in Cheonsu Bay was in August 2013, when we identified skin wounds on the rockfish caused by the nematodes escaping from their hosts. During this period, the accumulated mortality for 2 weeks was 1.4-22.4% in different farms. In addition, several pathogenic bacteria (Photobacterium damselae, Vibrio spp., and Streptococcus iniae) were isolated from the moribund rockfish; these were thought to be transmitted through the skin wounds caused by the nematodes.

• 한국식품영양과학회지
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• 제46권3호
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• pp.394-399
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• 2017

플라스틱 포장 폐기물로 인한 환경오염을 해결하기 위한 대안으로 생분해성 필름이 많이 연구되어 왔다. 본 연구에서는 우럭 껍질 젤라틴(RFG)과 nano-clay(Cloisite $Na^+$, 10A)의 복합필름의 특성에 관하여 연구하였다. 우럭 껍질로부터 젤라틴을 추출하여 sorbitol을 가소제로서 첨가한 단백질 필름을 제조하였고, 제조된 RFG 필름의 tensile strength(TS), water vapor permeability(WVP), water solubility(WS)는 각각 15.0 MPa, $2.70{\times}10^{-9}g\;m/m^2\;s\;Pa$, 53.8%였다. RFG에 nano-clay를 첨가한 복합필름은 TS가 증가하고 WVP와 WS는 감소하였다. XRD 분석과 SEM 측정 결과를 통하여 RFG/nano-clay 복합필름 내부에 박리형 구조를 형성함을 확인할 수 있었다. 결론적으로 본 연구 결과 RFG/nano-clay 복합필름은 생분해성 포장재로 적용될 수 있음을 시사한다.

• 수산해양교육연구
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• 제28권4호
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• pp.1068-1075
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• 2016

The suitable temperature and salinity for the long-distance transportation for the rockfish were investigated by assessing survival rate, metabolism, histological change. All experimental groups showed survival rates of 100%. Daily Oxygen consumption rhythm was decreased during nights and increased during days. Average oxygen consumption was significantly decreased as temperature and salinity were decreased. Ammonia excretion was significantly increased as temperature and salinity were decreased. Histological changes were observed in the skin and gill of the rockfish exposed to 10 psu under all the temperature conditions, with larger changes at $4^{\circ}C$. Further, nucleus deformation and uniformity in the cytoplasm were also observed.

• 한국어병학회지
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• 제20권2호
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• pp.99-108
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• 2007

본 연구는 V. harveyi의 luminescence 유무와 해수 어류에 대한 병원성의 관계를 알아보고자 non-luminous V. harveyi 와 luminous V. harveyi 분리 균주로 조피볼락에 대한 병원성 시험을 시행하였다. 시험 균주 V. harveyi 모두 haemolytic activity를 나타내었으며, 어체 내 생존능은 non-luminous V. harveyi 분리 균주 FR 2가 강한 생존능을 나타내었다. 또한 조피볼락에 인위 감염시, non-luminous V. harveyi 분리 균주 FR 2가 강한 병원성을 나타내었으며 luminous V. harveyi 분리 균주 VIB 391은 낮은 병원성을 나타내었다. 결론적으로 조피볼락에서는 non-luminous V. harveyi 분리 균주 FR 2가 강한 병원성을 나타내었으며 luminous V. harveyi 분리 균주 VIB 391은 매우 약한 병원성을 나타내어 luminescence의 유무에 따라 해수 어종에 대한 병원성의 차이가 있을 것으로 생각된다

• Fisheries and Aquatic Sciences
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• 제14권3호
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• pp.168-173
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• 2011

The purpose of this study was to obtain a fraction with high antioxidative activity from second rockfish gelatin hydrolysates (SRSGHs), which were hydrolyzed with Alcalase and Flavourzyme through ultrafiltration membranes with serial digestions for 1 and 2 h, respectively, and to investigate the feasibility of this fraction as a potential functional food ingredient. Among various fractions that were ultrafiltered from the SRSGH with four types of membrane (1, 5, 10, and 30 kDa), the SRSGH-III fraction, which permeated the 10 kDa membrane but not the 5 kDa membrane, showed the highest antioxidant activity (protection factor=5.13) and angiotensin-I-converting enzyme-inhibiting activity ($IC_{50}$=0.82 mg/mL). These results suggest that the SRSGH-III fraction from the SRSGH can be used as a functional food ingredient. However, further studies examining its antioxidant activity in vivo as well as the different antioxidant mechanisms are needed.

• 한국어류학회지
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• 제20권3호
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• pp.149-155
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• 2008

The effects of noise stress response on hematological parameters (hemoglobin, hematocrit and MCHC) and plasma parameters (cortisol, glucose and albumin) in Korean rockfish (Sebastes schlegeli), a very important commercial marine fish in Korea, were investigated. These parameters were analyzed on fish exposed to an explosion of noise. There were no significant differences or trends in hematological parameters (hematocrit; control $29.7{\pm}4.8%$, experiment 32.0 35.5%; hemoglobin; control $6.5{\pm}0.7g/dL$, experiment 6.2 7.8 g/dL; MCHC; control $19.6{\pm}0.6g/dL$, experiment 19.9~22.2 g/dL). However, plasma cortisol and glucose exhibited significant differences from start to finish and displayed the following patterns (cortisol; control $180.7{\pm}35.4ng/mL$, experiment 247.0 444.5 ng/mL; glucose; control $32.5{\pm}6.3mg/dL$, experiment 50.5 109.0 mg/dL). In addition, the glucocorticoid receptor (GR) mRNA expression and basal levels of various tissues (eye, gills, liver, intestine, skin and gonads) were investigated for the first time in this marine fish. When the Korean rockfish was exposed to explosive noise stress, the GR mRNA was expressed more in the gonads than in other tissues tested and was elevated significantly from two and four times in the liver and gills, respectively, after noise exposure.