• Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.12.1-12.8
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• 2016

Roe is the term used to describe fish eggs (oocytes) gathered in skeins and is one of the most valuable food products from fishery sources. Thus, means of processing are required to convert the underutilized yellowfin tuna roes (YTR) into more marketable and acceptable forms as protein concentrate. Roe protein concentrates (RPCs) were prepared by cooking condition (boil-dried concentrate, BDC and steam-dried concentrate, SDC, respectively) and un-cooking condition (freeze-dried concentrate, FDC) from yellowfin tuna roe. The yield of RPCs was in the range from 22.2 to 25.3 g/100 g of roe. RPCs contained protein (72.3-77.3 %), moisture (4.3-5.6 %), lipid (10.6-11.3 %) and ash (4.3-5.7 %) as the major constituents. The prominent amino acids of RPCs were aspartic acid, 8.7-9.2, glutamic acid, 13.1-13.2, and leucine, 8.5-8.6 g/100 g of protein. Major differences were not observed in each of the amino acid. K, S, Na, and P as minerals were the major elements in RPCs. No difference noted in sodium dodecyl sulfate polyacrylamide gel electrophoresis protein band (15-100 K) possibly representing partial hydrolysis of myosin. Therefore, RPCs from YTR could be use potential protein ingredient for human food and animal feeds.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.473-480
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• 2017

We investigated the nutritional characteristics of the uncooked Skipjack tuna Katsuwonus pelamis frame (U-STF) as a basic resource for preparing flavor-enriching concentrates. The bone rate based on the fish frame (FF) was 53.2% in U-STF, thus lower than those of cooked skipjack tuna frame (C-STF), the uncooked salmon frame (U-SF), and beef leg bone (BLB). The composition of FF had 48.6-58.0% moisture, 18.4-21.3% crude protein, 7.0-15.0% crude lipid, and 12.8-22.1% ash. Compared to the proximate composition of BLB, that of FF was higher moisture and crude protein but lower solids, crude lipids, and ash. The total amino acid contents of FF was 17.6-20.8 g/100 g, which was higher than that of BLB. The levels of calcium and phosphorus of FF were 4.7-8.5 g/100 g and 2.4-4.2 g/100 g, respectively, thus lower than those of BLB. The brix concentration of FF extract was $5.0-8.2^{\circ}$, being highest in U-STF extracts, followed by extracts of U-SF and then extracts of C-STF. Our results indicate that U-STF is an optimal resource for preparing flavor-enriching concentrates.

• Korean journal of food and cookery science
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• v.30 no.2
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• pp.146-152
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• 2014

This study surveyed consumers' sensory liking ratings of 3 types of developed brown rice products (brown rice nut waffles, Kimchi and tuna rice ball, sweet red-bean paste rice ball) and analyzed the drivers for liking or disliking the brown rice products. Each brown rice product had a brown rice to brown rice powder ratio of either: 100:0; 80:20; or 50:50. Forty consumers evaluated the acceptance of brown rice products on a 9-point hedonic scale and gave comments regarding liking or disliking each product. The results of the preference investigation analysis showed subjectivity depending on the brown rice product and the respondents' genders and ages. For brown rice nut waffles was affected by gender, age, and brown rice powder mixing ratio (p < 0.05). The variables "liking the aroma"; "liking the delicate flavor"; "liking the chewiness"; "liking the moistness"; "liking the softness"; "liking the harmony"; "liking the aftertaste" and "overall acceptability" did not differ significantly with the Kimchi and tuna rice ball. For the sweet red-bean paste rice ball product, the rates of liking the chewiness, stickiness, moistness, and softness of the 0% brown rice powder mix were all higher (p < 0.05) than were the rates of liking those same qualities in the 50% brown rice powder mix. Among all brown rice products, there were high correlations between the overall acceptability, liking the saltiness, liking the aroma, and liking the harmony. A preference investigation analysis showed that the brown rice product fillings were key factors to the products' overall acceptability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.6
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• pp.981-986
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• 2000

In the process of tuna for food, the unprocessed parts of the whole fish range from 30 to 35%, which are mostly used as animal feed stuff, and wasted. Thus, preliminary study on the recycling of the by-product was done to ultimately produce highly valuable products. The study was peformed on skin, skin flesh, tail flesh, dark flesh and abdominal flesh of the tuna. First, crude protein was the most abundant in the skin at 26.31%. About 21% of the crude protein were found in the other samples. Second, crude fat was greatly obtained in the skin at 15.58%. Interestingly, only 0.75% of crude fat was found in the dark flesh. Third, vitamin C and vitamin B group were highly measured in the abdominal flesh and the dark flesh, respectively. Importantly, docosahexaenoic acid (DHA, C22 : 6 $\omega$ -3) and eicosapentaenoic acid (EPA, C22 : 6 $\omega$ -3) which are highly unsaturated fatty acids, were abundant in the skin and skin flesh. To determine the effect of high temperature to the unprocessed parts, the samples were exposed to steam for 30 min. After this processing, 15-methylhexadecanoic acid (i-17 : 0) were in- creased in the skin flesh and the dark flesh. Furthermore, 3-hydroxytetradecanoic acid (3-OH 14 : 0), heptadecanoic acid (17 : 0), 2-hydroxyhexadecanoic acid (2-OH 16 : 0) and nonadecanoic acid (19 : 0) hat were not found before with steam were detected. The DHA and EPA in the dark flesh and the DHA in the skin were stable, respectively, even after the treatment.

• Korean Journal of Food Science and Technology
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• v.45 no.3
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• pp.376-381
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• 2013

In this study, we monitored total mercury and methylmercury concentrations in tuna, billfish, and deep-sea fish distributed in Seoul city. With the acquired data, we carried out statistical analysis and an exposure assessment for intake. The mean concentrations (mg/kg) of total mercury and methylmercury were $0.32{\pm}0.31/0.20{\pm}0.20$ for tuna, $0.43{\pm}0.48/0.20{\pm}0.17$ for patagonian toothfish, $0.99{\pm}0.72/0.51{\pm}0.40$ for billfish and $1.20{\pm}0.70/0.95{\pm}0.51$ for sharks, respectively. We found that sharks, billfish, patagonian toothfish, and tuna were more contaminated with total mercury and methylmercury, in sequence, and that 66% of the total mercury concentration consisted of methylmercury, on average. Although the estimated weekly intakes of methylmercury from commercial deep-sea fish were lower than the weekly intakes recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), we identified that the total mercury and methylmercury concentrations in tuna, billfish, and deep-sea fish continued to increase with the passage of time. Therefore, we confirmed the necessity of continuous monitoring and comprehensive analysis for general safety.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1417-1424
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• 2007

The food components of fish (skipjack tuna, yellowfin tuna, bluefin tuna, conger eel, salmon, Spanish mackerel, armored weasel-fish) frames and their hot-water extracts were investigated to explore their possibilities as resources for fish Gomatang. According to the results of volatile basic nitrogen and heavy metal, bluefin tuna and salmon frames were below the safety limits suggested by Codex Code. Thus, bluefin tuna and salmon frames appeared to be safe as basic ingredients for fish Gomtang. The major components of all hot-water extracts from fish frames were nitrogenous component. According to the results of extractive nitrogen and sensory evaluations of hot-water extracts from fish frames, the salmon frame was a good raw material as a basic ingredient of fish Gomtang. The calcium and phosphorus contents of hot-water extracts from salmon frame were 18.0 mg/100mL and 33.1 mg/100mL, respectively.

• Journal of Life Science
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• v.19 no.2
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• pp.277-283
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• 2009

Biogenic amines are generally formed through the decarboxylation of specific free amino acids by exogenous decarboxylases released by microbial species associated with the fish products and fermented feeds. This study was conducted to investigate the properties of e tuna waste regarding the control of degradation of biogenic amines (histamine, tyramine, tryptamine, putrescine, and cadaverine) that might be related with the anti-nutritional factor of the tuna waste that is used for manufacturing domestic fish meal. The values of pH and the salt content were 6.51, 3.35% in tuna waste and 5.58 and 5.83% in tuna fish meal, respectively. The strains and dominant bacteria tested in the tuna waste sample were 9.20, 9.29, 5.67, 7.82 and 7.58 log CFU/g of total bacteria, aerobic plate count (APC), total coliform (TC), Lactobacillus spp. and Bacillus spp., respectively. The main histamine forming-bacteria (HFB) in tuna waste were detected by silica gel thin-layer chromatography (TLC) and 7 histamine-forming bacterial species were isolated among microbes grown in selective medium. The histamine concentration was determined by detection of fluorescence of ο-phthaldialdehyde (OPA) derivatives using HPLC and the date were used to reconfirm the identities of the amine-producing bacteria. The 15 histamine- forming bacteria strains grown in trypicase soy broth (TSB) supplemented with 1% L-histidine (TSBH) were identified as Lactococcus(L.) lactis subsp. lactis, Klebsiella pneummonlae, L. garvieae 36, Vibrio olivaceus, Hafnia alvei and L. garvieae which were main dominant amine - producing strains, and Morganella morganii identified by 16S ribosomal RNA (rRNA) sequencing with PCR amplification. A Phylogenetic tree generated from the 16S rRNA sequencing data showed different phyletic lines that could be readily classified as biogenic amine forming gram-positive and negative bacteria.

• Journal of Aquaculture
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• v.5 no.2
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• pp.127-142
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• 1992

A feeding experiment was carried out to investigate the availability and feasibility of fish processing by-products as a substitute for frozen round fish in moist pellet diets for flounder, Paralichthys olivaceus. A control diet was prepared by incorporating $50{\%}$ frozen horse mackerel and $50{\%}$ commercial binder feed. In test diets the frozen horse mackerel of the control diet was replaced with either tuna scrap, tuna viscera, flatfish offal, deskinned hagfish, or tuna viscera ($20{\%}$) with frozen horse mackerel ($30{\%}$). Eighty flounders, 13.4 g in mean body weight, were stocked in 12 aquaria ($250\;{\ell}$ each) and fed six experimental diets for the first 28-day experiment. For the second 23-day experiment, forty flounders,44.8 g in mean body weight, were stocked and fed the same experimental diets. All treatments were duplicated. There were no significant differences in growth, feed efficiency and nutrient utilization among fish fed experimental diets containing either frozen horse mackerel, deskinned hagfigh, flatfish offal or tuna viscera with frozen horse mackerel. However, the feeding performances of fish fed experimental diets containing tuna scrap or tuna viscera were significantly lower than those of the control diet (P<0.05). There were no significant differences among the treatments on the proximate analysis values of the whole body. However, the crude lipid content of liver of the fish fed the experimental diet containing tuna scrap was significantly lower than that of the others. The results indicate that deskinned hagfish, and flatfish offal could be successfully substituted for frozen fish portion of moist pellet diets for flounder, but tuna viscera could only be partially substituted.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.427-434
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• 2008

Processing of collagen from yellowfin tuna (Thunnus albacares) abdominal skins was optimized by response surface methodology and central composite design. The values of independent variables at optimal conditions were NaOH concentration: 0.5 N, NaOH treatment time: 36.2 hr, pepsin concentration: 1:4.9 ratio (0.245%, w/v), and digestion time: 48.1 hr, respectively. The collagen content estimated under optimal conditions was 33.1%, and the actual experimental collagen content was 32.3%. Physicochemical properties of collagen from yellowfin tuna abdominal skin were investigated by amino acids analysis, SDS-PAGE, FT-IR, viscosity and denaturation temperature. Amino acids content of the collagen was 21.0%. SDS-PAGE pattern of the collagen showed two different $\alpha$-chain (${\alpha}_1$- and ${\alpha}_2$- chain), $\beta$-component and $\gamma$-component. The spectrum of FT-IR of the collagen showed wavenumber at 3,434, 1,650, 1,542 and $1,235\;cm^{-1}$ representing the regions of amide A, I, II and III, respectively. Relative viscosity of the collagen decreased continuously on heating up to $32^{\circ}C$, and the rate of decrease was retarded in the temperature range of $35-50^{\circ}C$. Denaturation temperature (Td) of the collagen solution (0.06%, w/v) was $31^{\circ}C$ and was lower than calf skin collagen ($35^{\circ}C$).

• The Journal of Fisheries Business Administration
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• v.54 no.3
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• pp.29-43
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• 2023

The United States is Korea's important trading partner, ranking third (13.7%) in exports of fishery products in Korea. The impact on exports to the United States is expected to be significant if the seafood import provisions under the MMPA are implemented in 2024 accordingly. It is expected that documents proving production information will be required for all items when exporting to the U.S. Therefore, this study attempted to examine the current status of exports and exporters in order to understand the actual conditions of major fishery products exported to the United States. Besides, there are currently no official system and procedures in Korea to prove production information for all fishery items, so we tried to suggest implications by examining distribution channels for major export items to the U.S. In this study, five items including seaweed and halibut as domestic aquaculture items, tuna and squid as deep-sea fishing items, and fish cake using imported raw materials were selected as the target items for distribution channel investigation. In addition, this study is meaningful in that it investigated the routes from production to processing, distribution, and export of each item and identified detailed distribution channel for major items exported to the U.S.