• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.2
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• pp.181-190
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• 2020

This study was conducted to estimate the optimum dietary DHA oil level and replacement level of enzyme treated fish meal (EFM) with sardine fish meal for juvenile Atlantic bluefin tuna Thunnus thynnus. Four diets were used: 1) EFM75 in which 75% EFM and 4% DHA oil were applied, 2) EFM60, with 60% EFM and 15% sardine fish meal, 3) DHA2 with 2% of DHA oil, and 4) SL as a raw fish feed. In a feeding trial, juvenile bluefin tuna (body weight 30.1 g) were randomly stocked into four experimental tanks (69 tones) and fed the experimental diets for 13 days. Fish weight gain was higher in the EFM75 and SL groups than in the DHA2 and EFM60 groups. The feed conversion ratio was lower in the EFM75 and DHA2 groups than in the EFM60 and SL groups. Survival was higher in fish fed the formulated diet groups (EFM75, EFM60 and DHA2) than in fish fed SL. This study clearly indicates that up to 10% dietary sardine fish meal can be used in juvenile T. thynnus diets, with an optimum dietary DHA oil level of approximately 3%.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.540-546
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• 1999

The purpose of this study was to investigate the antimicrobial effects and characteristics of protamine extracted from spermary of tuna. The result of amino acids analysis showed that the contents of arginine were 46%. It was 10% lower when compared to standard protamine (SP: Asama kasei LTD, Japan). Also, there were significant difference in the contents of proline adn glycine. The average molecular weights of main protein in TP were 13,400 Da, whereas those in SP were 11,300 Da and 2,600 Da. To increase antimicrobial activities of TP, pepsin or trypsin was treated at $37^{\circ}C$. After TP was hydrolyzed with pepsin (pepsin hydrolyzed protamine: PHP) for 4hrs, the average molecular weights of the main protein were 11,300 Da and 3,900 Da, and the antimicrobial activities were significantly increased compared to TP. After TP was hydrolyzed with trypsin (trypsin hydrolyzed protamine: THP) for more than 10 min, the average molecular weights of the main protein were below 2,500 Da. PHP had higher antimicrobial effects on some gram positive bacteria (Staphylococcus aureus, Lactobacillus helveticus, Lactobacillus plantarum) than SP. However, THP had no antimicrobial activities. When TP was hydrolyzed with pepsin (PHP), its antimicrobial activities increased in the same level with those of SP, and this increase might be resulted rather from the changes of molecular weights of the main protein than from the contents of arginine in protamine.

• Food Science and Preservation
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• v.30 no.5
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• pp.885-895
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• 2023

This study aims to investigate the production and characteristics of protein hydrolysates derived from tuna byproducts (TP) using various proteolytic enzymes and to compare the antioxidant activity of the resulting hydrolysates. The TP were subjected to enzymatic hydrolysis using five different proteases: alcalase, bromelain, flavourzyme, neutrase, and papain, and the antioxidant activities of the hydrolysates were evaluated. Subsequent analysis of the available amino group contents and sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns indicated a high degree of hydrolysis in TP after treatment with all the enzymes, except for papain. Based on the RC₅₀ values obtained from four different antioxidant analyses, all the hydrolysates exhibited similar antioxidant activity, except for the flavourzyme hydrolysate, which showed significantly higher scavenging activity against ABTS radicals and hydrogen peroxide than the other hydrolysates. These findings suggest that protein hydrolysates derived from TP hold promise as potential sources of natural antioxidants.

• 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 Fisheries and Aquatic Sciences
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• v.45 no.3
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• pp.215-223
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• 2012

This study was conducted to prepare canned skipjack tuna Katsuwonus pelamis in the mixture of isotonic beverage and tomato paste (ST-S) for use as a health food. An analysis of the time-temperature profile and viable cells showed that a reasonable F0 value for ST-S preparation was 4 min. The proximate composition of ST-S was 76.8% moisture, 20.2% crude protein, 0.8% crude lipid, 1.7% ash and 0.5% carbohydrate. The calorie content of ST-S was 94.8 kcal, which is 47.4% lower than that of commercial canned skipjack tuna in oil (ST-O) and 2.2% lower than that of commercial chicken breast in water (CB-B). The total amino acid content of ST-S was 18.54 g/100 g, which is 31.4% lower than that of ST-O and 7.9% lower than that of CB-B. The major amino acids in ST-S were aspartic acid and glutamic acid. An enrichment effect due to such minerals as phosphorus, potassium and iron would be expected on consuming 100 g of ST-S. The major fatty acids in ST-S were 16:0 (27.4%), 18:1n-9 (14.3%) and 22:6n-3 (27.8%), which are different from those in ST-O and CB-B. The major free amino acids in ST-S were glutamic acid (8.1%), histidine (38.6%) and its related dipeptide, such as anserine (15.7%). In an evaluation of taste, flavor and color, ST-S was found to be superior to ST-O and CB-B.

• Journal of Aquaculture
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• v.21 no.4
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• pp.272-277
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• 2008

We investigated the growth and survival in seedling production, and growth performance was compared with the different rearing tanks and protein source of formulated feed for juvenile Pacific bluefin tuna Thunnus orientalis (PBT). The survival rate at the end of nursery culture at 30 days after hatching was $0.69{\pm}0.40%$, and total length and mean body weight were $49.83{\pm}2.52\;mm$ and $1.03{\pm}0.09\;g$, respectively. Growth performance has no significant difference in fish reared by different tanks forms for 10 days. In order to develop an artificial diet, we evaluated the dietary utility of enzyme treated fish meal (Bio-CP, BIO) for juvenile PBT. Only diet BIO sustained similar growth and higher feed efficiency, and final carcass lipid content as compared to those of Sand lance (SL) These results revealed that BIO-CP a suitable dietary protein source, could sustain growth of PBT.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.230-237
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• 2018

This study investigated the food and nutritional characteristics of alkaline-insoluble fractions (AIFs) recovered from bastard halibut Paralichthys olivaceus (BH) and skipjack tuna Katsuwonus pelamis (ST) roes using the alkaline solubilization. The moisture content of AIFs ranged from 4.8% to 12.8%, and ST provided significantly better yields (9.5 for STAIF-11 and 7.1 g/100 g roe for STAIF-12) than did BH (P<0.05). The protein content of AIFs ranged from 71.7% to 79.2%, with the highest level yielded by STAIF-11 (6.8 g/100 g roe). The crude fat content of AIFs was 10.9-14.3% and the mineral content was 0.7-3.4%. The major mineral components of AIFs were sulfur, sodium, potassium, and phosphorus. Color values showed that BHAIFs were significantly brighter than STAIFs. Total contents of essential amino acids were significantly higher in STAIFs (47.5-49.5%) than in BHAIFs. The major essential amino acids found in AIFs from both sources were Val, Leu, Lys, and Arg. Therefore, AIFs were significantly superior to whole BH roe in terms of physicochemical and nutritional status, and we identified species-specific differences between BH and ST. Protein is a major component of AIFs recovered from fish roes, which suggests that they have potential for use as a protein source.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.1
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• pp.93-100
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• 2004

This study was carried out for analyzing pathological and epidemiological factors of osteoporosis and doing pilot test using trial compounds of tuna bone and oriental herbs based on the factors. Osteoporosis is originated from osteoblast, osteoclast, organic and inorganic factors etc. Therefore the pathology of osteoporosis is not simple because the cytokine, growth factors and hormones of the components are various a lot. Taking a view of epidemiological factors of type I osteoporosis, ageㆍmenarcheㆍcholesterolㆍBMI etc. have definite relation to them. So we can approach to aging or consumptive disease in oriental medicine, specifically differential diagnosis of blood depletion with deficiency of qi, deficiency of kidney, deficiency of yin, bony weakness etc. And it should be considered together with rules for maintaining good health or habit concomitantly. Therefore IL1ㆍ6 or TNF αㆍβ are generally used as molecular biological index for osteoblast and osteoclast because the most important index is bone mineral density and strength, but the factors like collagen and noncollagen protein must be accounted as biomarkers. Trial compounds generally showed favorable effects on accompanying subjective symptoms of osteoporosis in the pilot test for menopausal woman. But if she didn't have specific symptoms of osteoporosis there wasn't any specific change. And osteocalcin was increased in case of being under standard level, but wasn't changed in case of normal level. Therefore these trial compounds can be used as a funcdonal diet for type I osteoporotic patients or preventive measures.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.376-382
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• 2018

We investigated the effect of replacing tuna byproduct meal (TBM) and rice bran (RB) with fish meal (FM) and macroalgae (MA) in extruded pellets (EP) supplied as a diet to juvenile Abalone Haliotis duscus in aquaculture. In total, 80,000 juvenile abalone were distributed among eight indoor raceways and supplied with one of four experimental diets. The control diet consisted of FM, fermented soybean meal, corn gluten meal and shrimp meal as protein sources, with wheat flour and dextrin as carbohydrate sources; the control diet also contained MA. In the FM50 diet, TBM was replaced with 50% FM. In the MA 50 diet, RB was replaced with 50% MA. The final diet, FM50+MA50, included TMB and RB in place of 50% FM and 50% MA. Abalone were fed to satiation with little food leftover for 16 weeks. Weight gain and specific growth rate of abalone fed the control diet were greater than those of abalone fed the FM50 and MA50 diets, but not different from those of abalone fed FM50+MA50 diet. The proximate composition of abalone soft body did not vary according to experimental diets. Based on these results, it appears that the traditional commercial diet for juvenile abalone, comprising FM and MA, could be replaced with one containing 50% TBM and 50% RB without any retardation of growth.

• Applied Biological Chemistry
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• v.47 no.2
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• pp.197-201
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• 2004

In order to recycle animal by-products from food processing as food seasonings, pig bone (PB), chicken bone (CB) and tuna dark flesh (TDF) were studied. PB and CB extract prepared by hot water extraction for 18 h were hydrolyzed with protease and lipase. The DHs of PB and CB extract were increased to 70% and 80%, respectively, when Flavourzyme was treated after pancreatic enzyme treatment. When TDF was hydrolyzed with Alcalase and Flavourzyme, dry matter yield and total protein yield were around 22% and 9%, respectively. Also the free ammo acid content in hydrolysate reached up to 27% of total solid. The sensory properties of three hydrolysates containing 1% NaCl were, in order of their overall acceptance, TDF, PB and CB. Therefore, tuna dark flesh turned out to be the suitable animal by-product as raw material for seasoning ingredient.