• 한국수산과학회지
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• 제50권6호
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• pp.837-840
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• 2017

We developed a method to rapidly evaluate the freshness of fish using a sensor gas chromatography (SGC) system. Mackerel Scomber japonicus was stored at $4^{\circ}C$ for 12 days to create an environment similar to the natural decomposition process. Trimethylamine (TMA) content in mackerel muscle was measured at 3-day intervals using a spectrophotometer. The gas-phase concentration of TMA in whole mackerel was also determined using an SGC system. The muscle TMA content increased over time during storage, as did the gas-phase concentration of TMA. Therefore, this study demonstrated that an SGC system can be used to rapidly measure the gas-phase concentration of TMA in fish during processing.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.808-815
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• 2022

In this study, gamma-irradiated mackerel (Scomber japonicus) meat was stored in a refrigerator for 20 days to examine the physicochemical changes related to fishy smell. The effect of gamma irradiation on the inhibition of the activity of crude urease extracted from Vibrio parahaemolyticus was also evaluated. Increased levels of trimethylamine (TMA) and volatile basic nitrogen (VBN) content, which are the main components causing fishy smell, were significantly reduced by day 20 of storage after gamma irradiation, indicating that freshness was maintained during storage. The ammonia nitrogen contents of 3, 7, 10, and 20 kGy gamma-irradiated groups were significantly decreased by 6.5, 15.2, 17.4, and 23.9%, respectively, compared to non-irradiated groups on day 20 of storage. In addition, urease activity decreased in a gamma irradiation intensity-dependent manner. Volatile organic compounds (VOCs) were measured during the storage of gamma-irradiated mackerel meat. The contents of ethanol, 2-butanone, 3-methylbutanal, and trans-2-pentenal, which are known to cause off-flavors due to spoilage of fish, were significantly reduced by day 20 of storage. Therefore, gamma irradiation can be considered useful for inhibiting urease activity and reducing fishy smell during fish storage.

• 한국수산과학회지
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• 제51권1호
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• pp.79-90
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• 2018

Fish ages are critical information in fish stock assessments because they are required for age-structure models such as virtual population analysis and stochastic catch-at-age models, whose outputs include recruitment strengths, a spawning stock size (abundance or biomass), and the projection of a fish population size in future. However, most countries other than the developed countries have not identified ages of fish caught by fisheries or surveys in a consistent manner for a long time (e.g.,>20 years). Instead, data about fish body sizes (e.g., lengths) have been well available because of ease of measurement. To infer age compositions of fish in a target group using fish length data, we intended to improve the length frequency analysis (LFA), which Schnute and Fournier had introduced in 1980. Our study was different in two ways from the Schnute and Fournier's method. First we calculated not only point estimates of age compositions but also the uncertainty in those estimates. Second, we modified LFA based on the von Bertalanffy growth model (vB-based model) to allow both individual-to-individual and cohort-to-cohort variability in estimates of parameters in the vB-based model. For illustration, we used data about lengths of Korean mackerel Scomber japonicas caught by purse-seine fisheries from 2000-2016.

• Journal of Ecology and Environment
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• 제36권4호
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• pp.217-222
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• 2013

Sea temperature in the South Sea of Korea has been increased over the last decades. Seabirds are sensitive to changes in food availability in marine environment. In this study, we investigate the diet of Black-tailed gulls (Larus crassirostris) during the breeding season to identify changes of marine environment and biological response such as breeding performance in the South Sea of Korea. A total of 22 fish species or family (n = 128) from regurgitates by chicks were collected on Hongdo Island in 2002 and 2012. The most important prey item was Japanese anchovies (Engraulis japonicas). Proportion of Anchovy in diet increased in 2012 (70.5%) compared to 10 years ago (27.5%). Some species were newly found in 2012: Spotted chub mackerel (Scomber australasicus), Pacific sand lace (Ammodytes personatus), White ventral goby (Acanthogobius lactipes), Silver-strip round herring, Multicolorfin rainbowfish (Halichoeres poecilopterus), Silverside (Hypoatherina tsurugae), Surfperch (Neoditrema ransonneti) and Spotnape ponyfish (Leiognathus muchalis), but not in 2002. Especially, sub-tropic fish such as Kammal thryssa (Thryssa kammalensis), and Rosefish (Helicolenus hilgendorfi) were frequently observed in the diet of 2012. These results might reflect the increase of sea temperature in the South Sea of Korea.

• 한국수산과학회지
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• 제54권5호
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• pp.703-713
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• 2021

Mackerel Scomber japonicus is an excellent source of vitamins (A, D and B₁₂), omega-3 fatty acids, dietary protein and minerals. This study was conducted to prepare mackerel-based processed seafood products such as grilled product with super-heated (GM), tang (TM) and salad with sweet potato (SSM) using mackerel as senior-friendly seafoods and to examine their quality characteristics. The hardness of GM, TM and SSM were 240.3×1.0³, 21.7×1.0³ and 7.4×1.0³ N/m², respectively. The viscosity of SSM was 25,450 m·Pas. The nutritional content of mackerel-processed products was within the senior-friendly standard specifications for protein, vitamin C, vitamin B₂ (riboflavin) and vitamin B₃ (niacin) ing GM, protein, vitamin B₃ and calcium for TM, and protein, vitamin D, vitamin B₂ and vitamin B₃ in SSM. All the mackerel-processed products were safe as senior-friendly seafoods, since digestibility rates were 81.5% for GM, 87.9% for TM and 93.5% for SSM. The physical, nutritional and the sanitation results indicated that senior-friendly seafoods classified of the mackerel-processed products was step 1 for GM, step 2 for TM and step 3 for SSM according to the Korean Food Code and Korean Indusrty Standards.

• 수산해양교육연구
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• 제28권4호
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• pp.1152-1158
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• 2016

This study was used samples, mackerel (Scomber japonicas), Japanese Spanish mackerel (Scomberomorus niphonius), alaska pollock (Theragra chalcogramma), yellow croaker (larimichthys crocea) known as some of the major species fisheries products in Korea We were investigated temperature change during thawing processing, water holding capacity, drip loss, extractive-nitrogen and viable cell count by various thawing methods, thawing at the room temperature (TRT), hot-air thawing (HAT), aeration thawing (AT), high-frequency thawing (HFT). The temperature changes have taken 2~3 hours in HFT and 24 hours by TRT. The expressible drip loss was 0.47~0.87 g/100 g in HFT, 1.91~4.42 g/100g in TRT, 1.31~4.93 g/100g in HAT, and 2.01~4.59 g/100g in AE. The water holding capacity was higher samples thawing by HFT than other thawing methods. Extractive-nitrogen was 276~452 mg/100 g in HFT, 177.21~420.27 mg/100 g in TRT. Viable cell count was $10^2$ to $10^3$ in HFT, $10^3$ to $10^5$ in other thawing methods. The processing speed and uniformity by HFT was minimized the risk of product degradations (drip losses, deterioration of sensorial, chemical and physical characteristics, bacteria growth, etc.), thus helping to preserve at its best the product quality than those by thawing methods. Therefore, HFT was expected to make high-quality thawing products anticipate future thawing technology

• 생명과학회지
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• 제27권9호
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• pp.1011-1019
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• 2017

거문도 해풍쑥 추출물을 처리한 고등어의 저장 기간 동안의 품질 특성을 조사하였다. 5% 해풍쑥 추출물에 고등어를 2시간, 3시간, 4시간 처리한 후 개별 포장하여 $-20^{\circ}C$에 저장하여 실험하였다. 해풍쑥 추출물을 처리하지 않은 고등어(control)와 해풍쑥에 2, 3, 4시간씩 처리한 고등어의 염도는 2시간 처리한 고등어가 0.07%로 가장 낮은 수치를 나타냈다. pH는 모두 5.90~6.23를 나타냈고 산도는 15일째 감소 후 증가하는 경향을 나타냈다. 또한, 저장기간이 길수록 인장강도는 control은 증가하고, 2, 3, 4시간씩 처리한 고등어는 감소하였다. Volatile basic nitrogen(VBN) 함량은 control은 4.2~50.7 mg%, 2시간 처리한 고등어는 5.6~15.4 mg%로 control보다 가장 낮은 수치를 나타냈다. 2시간 처리한 고등어 제품에서 total polyphenol, total flavonoid 함량은 286.3~497.0 mg GAE/100 g, 177.5~385.6 mg QE/100 g를 나타냈다. DPPH, ABTS radical scavenging activity은 2시간 처리한 고등어 제품에서 50.6%, 61.3%를 각각 나타냈다. 전반적으로, 고등어를 SWM으로 단시간 처리하면 염도, pH, 산도, 경도, 항산화 활성 및 저장기간 연장과 같은 품질특성이 크게 향상되었음을 알 수 있다.