• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.1
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• pp.1-8
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• 2006

For the effective utilization of tuna processing byproducts such as roes of skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacores) as a food resource, the roes of skipjack and yellowfin tuna were examined on food component characteristics and also compared to those of Alaska pollack (Theragra chalcogramma). The concentrations of heavy metal in both roe of the skipjack and yellowfin tuna were below the reported safety limits, therefore, these roes appeared to be safe as a raw material for food resource. The contents of crude protein were 21.4% in the skipjack tuna roe and 21.5% in the yellow fin tuna roe, which showed to be the major component in tuna roes. The prominent amino acids of total amino acids were aspartic acid, glutamic acid, leucine and lysine, and these amino acids were comprise to be 38.4-41.2% of total amino acid in both tuna roes. The total lipid content were 2.1 % in the skipjack tuna roe and 2.0% in the yellofin tuna roe. The major component of total lipid was found to be triglyceride in both tuna roes (skipjack tuna roe, 93.3%; yellow fin tuna roe, 92.0%), which was high in the compositions of 16:0, l8:1n-9, and 22:6n-3. The content of DHA in total lipid of the tuna roes (skipjack tuna roe, 29.9%; yellowfin tuna roe, 36.3%) were higher than that of Alaska pollack roe (18.1%). Based on the results of the proximate composition, mineral, amino acid and lipid characteristic, roes of skipjack tuna and yellowfin tuna showed potential as a raw material for food.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.467-472
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• 2017

There is increasing interest in developing flavor-enriched concentrate using byproducts of skipjack tuna Ktsuwonus pelamis as a replacement for commercial beef bone extract concentrate (CBB-EC). This study was compared on sanitary and nutritional characteristics between skipjack tuna frame extract concentrate (ST-EC) and CBB-EC as a control of skipjack tuna frame extract concentrate. The moisture contents of CBB-EC and ST-EC 41.4-4.9% and 45.3%, respectively. The results of viable cell counts and E. coli assays suggested that CBB-EC and ST-EC is a safe and sanitary for use in food. There were no differences in peroxide values among CBB-ECs. The total amino acid contents in CBB-EC and ST-EC were 25.6-29.3 g/100 g and 37.9 g/100 g, respectively, and the major amino acids present glutamic acid, proline, glycine, alanine and arginine. Regardless of kinds of the mineral, mineral contents of ST-EC higher than those of CBB-EC. The major fatty acids were 16:0, 18:0 and 18:1n-9 in CBB-EC, 16:0, 18:1n-9 and 22:6n-3 in ST-EC. These results can be used as background information to develop flavor-enriched concentrates from byproducts of skipjack tuna as replacement for CBB-EC.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.684-693
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• 2017

We investigated methods for extracting histidine-containing low-molecular-weight (LMW) peptides such as anserine, carnosine and histidine from the edible meat of tuna byproducts. Extracts were treated by several methods including heat treatment ($80^{\circ}C$, 10 min), DOWEX ion exchange (IEC), ultrafiltration (UF), and carboxymethyl (CM)-cellulose column chromatography (IEC+CMC); then the levels of protein, total iron, histidine, carnosine, and anserine were measured. Extracts treated with IEC+CMC using CM-cellulose were analyzed for total iron, protein, histidine, and anserine content, which were $6.27{\pm}0.26mg/mL$, $5.20{\pm}0.21{\mu}g/mL$, 0.80 mg/mL, 0.208 mg/mL, and 4.40 mg/mL, respectively, in yellowfin tuna; and $9.05{\pm}0.82mg/mL$, $4.06{\pm}0.20{\mu}g/mL$, 1.62 mg/mL, 0.012 mg/mL, and 7.28 mg/mL in bigeye tuna. By comparison in IEC-UF treated extracts, protein, total iron, and histidine content decreased by 43%, 73%, and 27% in yellowfin and 0.4%, 54%, and 23% in bigeye tuna, wheres carnosine and anserine content increased by 22% and 17%, respectively. Freeze-dried (FD) extracts exhibited similar trends as non-dried extracts, i.e., dipeptide content increased with purification steps, whereas pro-oxidant (total iron and protein) content decreased. IEC+CMC treated FD extracts had the highest anserine, content, and the greatest reductuion in pro-oxidants.

• 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.36 no.6
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• pp.766-772
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• 2007

The enzymatic hydrolysate of skipjack tuna cooking drip with good functionality was prepared by incubation with Alcalase for 30 min. For the preparation of functional seasoning sauce with enzymatic hydrolysate (SSE), the additives, such as concentrated enzymatic hydrolysate (100 mL), yeast extract powder (0.7 g), lactose (0.4 mL), liquid smoke (0.3 g) and sea tangle powder (1.4 g), were added to the enzymatic hydrolysate and boiled before filtration. The proximate composition of SSE was 11.8% for crude protein, 5.77 for pH and 11.9% for salinity. The SSE was higher in the crude protein, while lower in the salinity than commercial seasoning sauce. ACE inhibitory activity ($IC_{50}$) and antioxidative activity (PF) of SSE were 6.2 mg/mL and 1.14, respectively, which were superior to those (9.9 mg/mL in IC50 and 0.91 in PF) of commercial seasoning sauce. The free amino acid content (1,905.2 mg/100 mL) and taste value (58.65) of SSE were higher than in those (712.7 mg/100 mL and 34.30, respectively) of commercial sauce. Total amino acid content of SSE (10,965 mg/100 mL) was higher than that (4,818 mg/100 mL) of commercial sauce. The major amino acids of SSE were glutamic acid (12.2%), proline (11.0%), histidine (10.7%) and glycine (9.9%). The results suggested that SSE could be commercially sold.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.3
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• pp.261-268
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• 2006

Fish-frames are processing byproducts, which are left after obtaining fillets or muscle during fish processing. The fish-frame generally consists of muscle, collagen, calcium, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). We used fish-frame powder (FFP) of chum salmon and skipjack tuna to prepare and characterize snacks for human consumption with different proportions of FFP. The crude protein and lipid contents of fish-frames were 16.3 and 9.4% for chum salmon and 18.6 and 8.3% for skipjack tuna, respectively. The volatile basic nitrogen (30.6 mg/100 g) and browning index (0.393) of FFP from chum salmon were lower than those of FFP from skipjack tuna. Thus, the FFP of chum salmon was better for making snacks than that of skipjack tuna. Five snacks were prepared with 0, 10, 20, 30, and 40% (w/w) substitution ratios of FFP from chum salmon. The moisture content of the snacks decreased (33.6 to 11.5%) with increasing FFP substitution ratio, whereas crude ash (2.9 to 7.5%), protein (11.4 to 18.4%) and lipid (13.7 to 35.1%) increased. Sensory scores for the texture and taste of the snack with 30% FFP were significantly higher (p<0.05) than those for other snacks; the color and flavor scores of all snacks did not differ significantly. The major fatty acids in the snacks were 16:0 and 18:0 as saturates, 18:1n-9 as monoenes, and 18:2n-6 and 18:3n-3 as polyenes. Snacks with FFP contained small amounts of EPA (0.5 to 0.8%) and DHA (1.3 to 1.8%) in the total lipid composition. The total amino acid content (16.08 g/100 g) of the snack with 30% FFP was higher than that of the snack without FFP (11.18 g/100 g), and the major amino acids were aspartic acid, glutamic acid, glycine, leucine, and lysine. The calcium and phosphorus contents of the snack with 30% FFP were 1,272 mg/100 g and 854 mg/100 g, respectively, and their ratio was the optimal range (2:1 to 1:2) for body absorption efficiency.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.881-888
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• 2007

For the use of skipjack tuna cooking drip (STC) as a source of functional seasoning, the STC was hydrolyzed with various commercial enzymes, such as Alcalase, Flavourzyme, Neutrase and Protamex, and its hydrolysate was also investigated on the food component characteristics. The hydrolysate incubated with Alcalase for 30 min (HA30) showed 56.8% for angiotensin I converting enzyme (ACE) inhibitory activity and 1.18 for antioxidative activity, which were high or similar compared to the other enzymatic hydrolysates. There were no differences in ACE inhibitory activity and antioxidative activity among HA30, two-step enzymatic hydrolysates, and ultrafilterates (molecular weight cut off, 10 kDa). The HA30 was very stable on the digestive enzymes, such as chymotrypsin, pepsin, trypsin according to the TCA (trichloroacetic acid) soluble index. The results suggested that skipjack tuna cooking drip could be used as a source for preparing functional seasoning sauce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.5
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• pp.595-602
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• 2007

This study was conducted to investigate on food component characteristics of seafood cooking drips (skipjack tuna cooking drip, octopus cooking drip and oyster cooking drip) as a source of functional seasoning. Heavy metal contents of seafood cooking drips were below food safety level. Among seafood cooking drips concentrated to 5 folds, the crude protein content was the highest (18.1%) in skipjack tuna cooking drip (SCD). The free amino acid content and taste value were higher in SCD than in other seafood cooking drips, and the major free amino acids were glutamic acid and aspartic acid. Total amino acid content of SCD was 16.2 g/100 mL and the major amino acids were glutamic acid (11.9%), proline (9.2%), glycine (9.1%) and histidine (11.5%). SCD in comparison with other seafood cooking drips showed the highest angiotensin I converting enzyme (ACE) inhibitory activity at $IC_{50}$ of 14.1 mg/mL. These results suggested that SCD could be used as a source of functional seasoning.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.3
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• pp.380-388
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• 2005

Lipid characteristics of 6 species of fish frame (armored weasel-fish, AW; chum salmon, CS; spanish mackerel, SM; common mackerel, CM; conger eel, CE and skipjack tuna, ST) were studied by determining total lipid (TL) contents, lipid classes, and fatty acid composition. The highest yield of bone was obtained from ST frame (64.2%), followed by CS frame (57.9%), CE frame (54.6%), A W frame (41.6%), SM frame (41.7%), and CM frame (32.6%). The highest neutral lipid content was also found in total lipid (TL) from SM bone (23.3 g/100 g), followed by TL from CE bone (21.5 g/100 g), CS bone (16.0 g/100 g), and CM bone (15.5 g/100 g), while those from ST and A W bones were 7.2 g/100 g and 0.4 g/100 g, respectively. The prominent lipid classes of neutral lipids (NL) from all fish bones and muscles were triglyceride (TG), however, which was much lower in AW than in other fishes. The percentages of EPA and DHA in NL from fish bone were in the descending order of CS (29.3%), ST (27.1%), AW (27.0%), CM (25.7%), SM (21.6%), and CE (14.9%). Based on the lipid characteristics, the CS frame was the best resource for extraction of a functional lipid.