• Fisheries and Aquatic Sciences
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• v.26 no.6
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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.

• 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.

• Biomedical Science Letters
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• v.26 no.4
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• pp.360-367
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• 2020

Tuna skin byproduct extract (TSB) was used as a biocompatibility film base material, and its composite film with gellan gum (GG) was prepared. In addition, Pinus thunbergii cone extract (PTCE) was incorporated into the film to provide anti-oxidant and anti-bacteria activities. The tensile strength (TS) of the TSB/GG composite films increased with increasing GG content, whereas elongation at break (E) decreased. TSB/GG film at a ratio of 0.5:0.5 (w/w) showed the most desirable TS and E values. Based on scavenging free radical potentials and disc diffusion method results against growth of bacteria, antioxidant and anti-bacteria activities of films increased with increasing PTCE concentration. Accordingly, this study showed that TSB/GG could be used as a film material while the TSB/GG composite film containing PTCE can be utilized as functional packaging.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.594-597
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• 2008

Natural products have been used to treat many neurological illnesses such as Alzheimer's disease. In the present study, the effects of the water extract of smoke-dried skipjack tuna (WSST), which is used as a traditional seasoning in Japan, as well as its fractions on acetylcholinesterase (AChE) inhibition in vitro and on memory in scopolamine-induced amnesia mice in vivo were evaluated. Bio-Rad P-2 gel permeation chromatography revealed the presence of 7 peaks and AChE significantly inhibited peak 3 and 5. When in vivo behavioral studies were conducted, a passive avoidance test revealed that treatment with 50 and 100 mg/kg WSST as well as with fraction 3 and 5 improved the loss in memory retention induced by scopolamine. These results suggest that skipjack tuna extract and its fractions improve memory deficits and that these substances are suitable for use in healthy foods designed to improve memory deficits induced by aging and Alzheimer's disease.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.4
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• pp.219-225
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• 2005

We studied the anticancer, antioxidative, ACE inhibitory, antithrombic, and cerebral ischemia inhibitory activities, of low molecular weight substances fractionated from the seasoned and smoked products of skipjack tuna (Euthynus pelamis). Low molecular weight substances fractionated from the liquid extract of seasoned and smoked skipjack tuna powder showed 7 peaks on gel permeation chromatography. Anticancer activity was the highest at Peak 3 $(54.23%)$ followed by Peak 4 $(41.58\%)$. The potency order of antioxidative activity was the highest at Peak 3 $(94.14\%)$ followed by Peak 2 $(82.07\%)$ and Peak 5 $(81.24\%)$. ACE inhibitory activity was the highest at Peak 3 $(67.27\%)$ followed by Peak 5 $(45.62\%)$. But there was weak anti thrombotic effect (PT and APTT) in the low molecular weight substances of the seasoned and smoked products of skipjack tuna. Cerebral ischemia inhibitory activity was the highest at Peak 3 $(80.0\%)$ followed by Peak 5 $(40.0\%)$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.127-133
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• 1999

The purpose of this study was to determine the optimum hydrolysis conditions for the production of enzymatic hydrolysate from tuna boiled extract (TBE) using membrane (molecular weight cut off 10,000Da) reator. The tuna pyloric caeca crude enzyme (TPCCE) was identified as the most suitable enzymes for the hydrolysis of TBE. The optimum hydrolysis conditions of TBE in the batch reactor were $40^{\circ}C$, pH 9 and substrate to TPCCE ratio 50 (w/w). For 6hr under the above conditions, $70\%$ of the total amount of initial TBE was hydrolysed. The optimum hydrolysis conditions of TBE in the membrane reactor were $40^{\circ}C$, pH 9, enzyme 0,1 g/$\ell$, volume 1$\ell$ and substrate to enzyme ratio 100(w/w). The degree of hydrolysis of TBE was above $60\%$ for 3 hr. The TBE hydrolysate were prepared with $5\%$ TBE solution under the optimum hydrolytic conditions in the membrane reactor

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.353-366
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• 1992

This study was devised to purify the compound from tuna that have cytotoxic activities against various cancer cell lines and to observe its immunopotentiating activities. The cytotoxic compound was partially purified 277 fold, from petroleum ehter extract (crude extract) of tuna by silicic acid column chromatography (fraction D) and thin layer chromatography (Spot I). Cytotoxic activity was monitored using human colon cancer cell, HCT-48. The active compound (Spot I) was composed of seven materials which are fatty acids of four kinds ($C_{14:0},\;C_{16:0},\;C_{17:1},\;and\;C_{18:0}$) and unknown three fat materials. The active compound has cytotoxic activities against various cancer cell lines, that is, murine leukemic lymphocytes (L1210, P388) and human rectal (HRT-18) and colon cancer cells (HCT-48, HT-29). The patterns of size distribution of HCT-48 cells in the medium containing tuna extract were shifted to direction of the small size region. Also, the microscopic shape of HCT-48 cells were shrinked and distracted. The number of plaque forming cell and immunoglobin fraction of serum protein obtained from tuna-treated mice were increased, but natural killer cell activity was not affected.

• KSBB Journal
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• v.30 no.6
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• pp.326-331
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• 2015

The anti-inflammatory effect of tuna heart water extract (THWE) was investigated using lipopolysaccharide-induced inflammatory response in this study. Anti-inflammatory effect was detected by the cell proliferation and the production levels of nitric oxide, pro-inflammatory cytokines such as interleukin-6 (IL-6), IL-$1{\beta}$, and tumor necrosis factor-alpha. As a result, there were no cytotoxic effects on proliferation of macrophages treated with THWE compared to the control. The production of pro-inflammatory cytokines was remarkably suppressed compared with that of the LPS only group. These results suggest that THWE exerts the anti-inflammatory property by inhibiting production of inflammatory factors and may be a potential material for anti-inflammatory therapy.

• 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.

• 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.