• 한국수산과학회지
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• 제45권6호
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• pp.635-639
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• 2012

Thawing is very important in tuna canning because it affects the yield and quality of the canned tuna, and productivity. The effects of vacuum thawing on the quality, yield, and thawing times of frozen skipjack were compared with conventional water immersion thawing. The time required to thaw frozen skipjack tuna (weight 2.5-3.0 kg) from $-10^{\circ}C$ to $-2^{\circ}C$ was 75, 60, and 37 min at a pressure of 17, 23, and 31 mmHg, respectively, corresponding to temperatures of 20, 25, and $30^{\circ}C$. The thawing time decreased with increasing pressure. Vacuum thawing shorten the thawing time by 58-80% compared with water immersion thawing at $20^{\circ}C$, and there was less difference between the core and skin temperatures than with water immersion thawing. No significant change in pH or histamine was observed according to thawing method, while the volatile basic nitrogen (VBN), trimethylamine (TMA), and K value were lower with vacuum thawing than water immersion thawing. Based on these results, we believe that vacuum thawing minimizes the biochemical and microbial changes that occur while thawing frozen skipjack tuna.

• 수산해양기술연구
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• 제50권3호
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• pp.310-317
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• 2014

This study was conducted to investigate the attractant substances of different solvent fractions of mackerel and tuna viscera. Mackerel and tuna viscera were extracted with methanol and the resultant were fractionated with n-hexane, chloroform, ethyl acetate, n-butanol and water. The chemical compounds such as free amino acid, fatty acid, nucleotide related compounds contents were estimated for mackerel, tuna viscera and various fractions. These fractions were also subjected to attracting experiments in water tank to estimate attracting effects. The aqueous fractions of mackerel and tuna viscera showed the highest attraction effect on swimming crab. The major chemical compounds of the aqueous fractions were histidine, taurine, cysteine, glutamic acid, inosine monophosphate (IMP) and inosine (HxR) for mackerel and arginine, glutamic acid, aspartic aid, alanine, IMP and hypoxanthin (Hx). Results indicated that higher polarity compounds, such as amino acid and nucleotide related compounds have higher attraction activities than nonpolar substances such as neutral lipid.

• Fisheries and Aquatic Sciences
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• 제26권6호
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• pp.393-405
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• 2023

The aim of this research was to enhance the flavor of visceral extracts from skipjack tuna. Flavor precursors and the optimum condition for the Maillard reaction were determined. The flavor extract was prepared from the tuna viscera using Endo/Exo Protease controlled in 3 factors; temperature, enzyme amounts and incubation time. The optimal condition for producing tuna viscera protein hydrolysate (TVPH) was 60℃, 0.5% enzyme (w/w) and 4-hour incubation time. TVPH were further processed to tuna viscera flavor enhancer (TVFE) with Maillard reaction. The Maillard reactions of TVFE were conducted with or without supplements such as xylose, yeast extract and methionine. The Maillard volatile components were analyzed with gas chromatography-mass spectrometry. Sixteen volatiles such as 2-methylpropanal, methylpyrazine, 2,5-dimethylpyrazine, dimethyl disulfide and 2-acetylthaizone were newly formed via Maillard reaction and the similarity of volatile contents from TVPH and TVFE were virtualized using Pearson's correlation integrated with heat-map and principal component analysis. To virtualize aromagram of TVPH and TVFE, odor activity value and odor impact spectrum (OIS) techniques were applied. According to OIS results, 3-methylbutanal, 2-methylbutanal, 1-octen-3-ol 2,5-dimethylpyrazine, methional and dimethyl trisulfide were the potent odorants contributed to the meaty, creamy, and toasted aroma in TVFE.

• 한국수산과학회지
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• 제56권5호
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• pp.741-748
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• 2023

This study evaluated the supplemental effects of linseed oil (LO) as a substitute for docosahexaenoic acid oil (DHAO) in the diet of juvenile Atlantic bluefin tuna. A control diet (DHA) was formulated to contain 65% enzyme-treated fish meal and 3% of DHAO. A LO diet was formulated to contain 1% LO replacing 1% DHAO in DHA diet. In a feeding trial, 300 juvenile bluefin tuna (initial body weight 1.15 g) were randomly divided into two concrete tanks (70 ton capacity) and fed one of the experimental diets for 13 days. Weight gain was higher in the LO group (519%) than in the control (443%) while survival and protein digestibility were similar between groups. The biological assessment of the tuna digestive organs did not differ between the DHA and LO groups. The fatty acid composition of the carcass showed that α-linolenic acid was only observed in the LO group, and there was no difference in the composition of eicosapentaenoic acid and docosapentaenoic acid between the groups. These results indicate that LO could be a dietary good oil source for Atlantic bluefin tuna without apparent negative effects.

• 수산해양기술연구
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• 제32권1호
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• pp.24-32
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• 1996

This paper described on relation between the catches of tuna and the distribution of water temperature of eastern fishing ground of Tropical region in the Pacific Ocean. The data of catches and water temperature used in this paper were based log book which # 27 CHENG RONG(Gross tonnage : 399 ton) had been worked eastern fishing ground(Lat : 09$^{\circ}$N- 14$^{\circ}$S, Long : 115$^{\circ}$- 149$^{\circ}$W)from January to October, 1991. The obtained result are as follows : 1. On the relation between the catches and the geographical distribution, bigeye tuna was higher catches at Lat 4$^{\circ}$- 9$^{\circ}$N, Long 135$^{\circ}$- 139$^{\circ}$W area in the equatorial counter current region where surface water temperature was range of 27.5$^{\circ}C$ to 27.9$^{\circ}C$, yellowfin tuna was higher catches at Lat 4$^{\circ}$- 9$^{\circ}$S, Long 145$^{\circ}$- 149$^{\circ}$W in the south equatorial current region where surface water temperature was range of 28.$0^{\circ}C$ to 28.4$^{\circ}C$ and albacore tuna was higher catches at Lat 10$^{\circ}$- 14$^{\circ}$S, Long 120$^{\circ}$- 124$^{\circ}$W area in the south equatorial current region where surface temperature was range of 26.5$^{\circ}C$ to 26.9$^{\circ}C$ 2. On the relation between catches and distribution of vertical water temperature, bigeye tuna was higher catches at the water temperature of 1$0^{\circ}C$ to 12$^{\circ}C$ on depth layer between 300m and 360m, yellowfin tuna was higher catches at the water temperature of 15$^{\circ}C$ to 19$^{\circ}C$ on depth layer between 180m and 280m and albacore tuna was higher catches at the water temperature of 12$^{\circ}C$ to 14$^{\circ}C$ on depth layer between 280m and 310m. Above the result, it seemed that bigeye tuna distributed deeper layer than yellowfin and albacore tuna.

• 한국어류학회지
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• 제20권2호
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• pp.105-111
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• 2008

다랑어낚시 및 사용미끼에 따른 어획률을 비교하기 위해, 2006년 9~10월간 태평양 중동부 해역에서 다랑어연승 시험조사가 수행되었다. 일반선형모형(GLM)을 이용하여 재래식 다랑어낚시 1종(J4)와 환형낚시 3종(C15, C16, C18), 미끼 5종(고등어(CM), 전갱이(JM), 밀크피쉬(MF), 정어리(SD), 오징어(SQ)) 및 낚시심도를 나타내는 낚시 순번들이 눈다랑어 어획률(1,000낚시당 마리수)에 미치는 효과를 평가하였다. 총 28회 조업에서 낚시순번 간 눈다랑어 어획률에는 유의한 차이가 인정되었다. GLM분석에서 낚시순번에 의한 눈다랑어 어획률 편차는 33%로 나타났다. 미끼 종류 간 어획률 차이는 그 편차가 2.7%로 적게 나타났고, 낚시형 4종 간 그 차이는 매우 적어 유의하지 않게 나타났다. 따라서, 낚시형 및 미끼 종류의 선택은 다랑어 연승어업에서 눈다랑어 어획률 차이에 영향을 주지 않는 것으로 평가되었으나, 어획수심을 나타내는 낚시순번은 눈다랑어 어획률에 영향을 주는 요인으로 판단되었다.

• 한국식품영양과학회지
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• 제46권4호
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• pp.465-472
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• 2017

본 연구에서는 고품질 인조육의 개발을 위하여 압출성형 인조육에 가공 부산물의 활용 측면에서도 장점을 지닌 참치 톱밥을 첨가하여 압출성형 공정을 거친 후 이화학적 특성에 대하여 살펴보았다. 압출성형 원료는 탈지대두분 65%에 분리대두단백 25%, 옥수수 전분 10%를 혼합한 것을 기본 배합시료로 설정하였고, 기본 배합 100%, 기본 배합에 참치 톱밥 15%를 첨가한 것과 참치 톱밥 30%를 첨가한 것, 세가지 시료를 제작하였다. 원료 사입량은 100 g/min, 스크루회전 속도 250 rpm, 사출구 온도 $140^{\circ}C$, 수분함량은 50%로 고정하여 압출성형한 후 비길이, 밀도, 파괴력, 조직잔사지수, 보수력, 조직감 분석, 수용성 질소 지수, 단백질 소화율, DPPH 라디칼 소거 활성을 실시하였다. 참치 톱밥의 첨가 함량이 높을수록 파괴력과 밀도는 감소하였고 단면 팽화율과 비길이는 증가하였다. 또한, 참치 톱밥 첨가 함량이 높을수록 조직잔사지수와 보수력은 감소하였으며 수용성 질소 지수와 단백질 소화율도 다소 감소하였다. DPPH 라디칼 소거 활성에서는 참치 톱밥의 첨가 함량이 높을수록 값이 증가하였으나 저장 기간이 30일과 60일로 길어짐에 따라 값이 감소하는 경향을 보였다. 산패도의 측정값은 참치 톱밥의 첨가 함량이 높을수록 감소하는 경향을 보였으나 60일 이후부터는 참치 톱밥의 첨가 함량이 높을수록 다소 증가하여 150일 이후에는 유의적 차이를 보였다. 기본 배합 시료에 참치 톱밥을 첨가하면 유연한 조직감과 영양적 가치를 보존하면서 항산화 기능이 증진되었다.

• 수산해양기술연구
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• 제45권1호
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• pp.22-33
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• 2009

Ecological risk assessment(ERA), developed in Australia, can be used to estimate the risk of target, bycatch and protected species from the effects of fishing using limited data for stock assessment. In this study, we employed the ERA approach to estimate risks to tunas, billfishes, sharks, sea turtles and other species by the Korean tuna longline fishery in the Western and Central Pacific Ocean using productivity and susceptibility analyses of the ERA based on low(<1.30), medium(1.30-1.84) and high risk(>1.84). Albacore, bigeye, yellowfin, skipjack and bluefin tunas were generally evaluated in the medium risk. The susceptibility of tuna species, however, had higher risks than the productivity. Billfishes were also at medium risk, while sharks were at high risk by the tuna longline fishery. The risk of productivity was generally high, because most sharks caught by the tuna longline fishery have high longevities, i.e., over 10 years, including ovoviviparous species. Susceptibility, which is related with the selection of fishing gear, was also high, because the longline fishery has no gear modifications to prevent bycatch of protected species. Not only target tuna species were influenced by the tuna longline fishery in the Western and Central Pacific Ocean, but also nontarget species, such as pomfret, mackerels rays, sea turtle were done. Ecosystem-based fishery assessment tools, such as productivity and susceptibility analysis(PSA), have the ability to provide broad scientific advice to the policy makers and stakeholders.

• 한국수산과학회지
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• 제48권4호
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• pp.489-497
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• 2015

To reveal the spatial and temporal variability in the distribution, growth, and maturation of skipjack tuna Katsuwonus pelamis in the western tropical Pacific, we compared two El $Ni{\tilde{n}}o$-Southern Oscillation (ENSO) signals and the sea surface temperature (SST) in the main fishing area with fishery and biological data. An index of skipjack tuna distribution was calculated using Korean purse seine fishery data from 1985 to 2003. Biological data for skipjack tuna were collected monthly from Korean catches during the 1994-2003 period. The catch was more closely related to the SST in the main fishing area than to the ENSO signals. However, cross-correlated function analysis showed delayed interactions between abiotic and biotic factors. The El $Ni{\tilde{n}}o$ events preceded the eastward movement of the fishing center by 2-3 months. El $Ni{\tilde{n}}o$ had a positive effect on the skipjack tuna catch, and the change in the Southern Oscillation Index (SOI) preceded the catch fluctuation by ca. 5-7 months. In addition, negative El $Ni{\tilde{n}}o$ effects on gonad maturation and the mean length of skipjack tuna were detected with time lags of 12 and 7 months, respectively. The length frequency indicated that the regime-specific growth pattern at each discrete period seemed to be related to the ENSO.

• 한국수산과학회지
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• 제53권3호
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• pp.423-431
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• 2020

This study was conducted to investigate in vivo and in vitro digestibility in juvenile Atlantic Bluefin tuna Thunnus thynnus. In vivo digestibility was compared between four experimental diets to determine the optimum dietary inclusion level of an enzyme-treated sardine fish meal (EFM) and sardine fish meal (FM). The experimental diets were as follows; EFM75 (75% EFM), EFM60 (60% EFM and 15% FM), FM75 (75% FM) and SL (frozen sand lance) as a raw fish feed. Feces of Bluefin tuna (90.3 g) were collected both by siphoning from a 700 L cage and by dissection in 69 ton concrete rearing tanks. For the siphoning method, protein digestibility was higher in the tuna fed SL diet than that of other groups. The lowest protein digestibility was observed in FM75. For the dissection method, protein digestibility was higher in tuna fed EFM75 diet than that of other groups. The lowest protein digestibility was observed in the EFM60 group. In vitro digestibility was compared in six protein sources to find an alternative source of EFM for the tuna feed. The highest in vitro digestibility was observed in EFM (92%) followed by low temperature FM (72%), meat meal (65%), feather meal (60%), sardine fish meal (57%) and poultry by-product meal (55%).