• 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.

• Proceedings of the Korean Society of Life Science Conference
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• 2001.09a
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• pp.96-96
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• 2001

• Fisheries and Aquatic Sciences
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• v.25 no.7
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• pp.390-402
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• 2022

In this study we investigate physical and chemical characteristics of immature and mature skipjack tuna (Katsuwonus pelamis) roes in fresh and dried forms. Fresh roes were studied for histological structure and also dried by three methods: hot air drying (HD), vacuum drying (VD) and freeze drying (FD). The obtained roe powders were analysed for proximate composition, color value, fatty acid composition, amino acid profile, equivalent umami concentration (EUC) and protein pattern. Unyolked oocytes were more common in immature roes, while fully yolked oocytes were more common in mature roes. All dried tuna roes contained high content of protein and lipid (69.31%-70.55% and 11.14%-16.02%, respectively). The powders obtained by FD provided the highest lightness value (L^*). The main fatty acid found in all roe powders was docosahexaenoic acid (DHA) (23.49%-27.02%). Glutamic acid, leucine, and aspartic acid were the three most abundant amino acids found in the powders (13.58-14.61, 8.06-8.42, and 7.81-8.39 g/100 g of protein, respectively). The mature roe powder obtained from HD provided the highest EUC value (73.09 g monosodium glutamate/100 g of samples). The protein band at molecular weight of 97 kDa (vitelline) represented the major protein. Therefore, dried tuna roe could be a functional ingredient source of protein and lipid rich in DHA and it also has potential to be used as taste enhancer with umami compound.

• 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.53 no.2
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• pp.165-173
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• 2020

Fish roe is among the most valuable food resources produced by fisheries. Raw fish roe requires processing for conversion into hygienic, marketable, and consumer-acceptable forms. In this study, to investigate the food compositional characteristics of various types of fish roe, we applied vacuum freeze-drying to prepare fish roe concentrates (FRCs) from roe of Alaska pollack Theragra chlcogramma, bastard halibut Paralichythys olivaceus, and skipjack tuna Katsuwonus pelamis. The FRC yield ranged from 22.7 to 26.7 g/100 g roe. The major constituents of FRCs were protein (65.4-79.6%), moisture (2.8-6.2%), lipids (8.5-18.3%), and ash (4.8-7.2%). Potassium, sulfur, sodium, and phosphorus were the major mineral elements of FRCs, and the major amino acids were aspartic acid (9.0-10.4 g/100 g protein), glutamic acid (13.2-14.5 g/100 g protein), lysine (8.4-8.6 g/100 g protein), and leucine (8.3-9.7 g/100 g protein). Vacuum freeze-dried FRCs differed among fish species in terms of amino acid composition and electrophoresis protein band distribution. Therefore, FRCs are an excellent source of protein nutrition and an appropriate protein fortification material in human foods or animal feed.

• Fisheries and Aquatic Sciences
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• v.19 no.3
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• pp.14.1-14.10
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• 2016

Isoelectric solubilization/precipitation (ISP) processing allows selective, pH-induced water solubility of proteins with concurrent separation of lipids and removal of materials not intended for human consumption such as bone, scales, skin, etc. Recovered proteins retain functional properties and nutritional value. Four roe protein isolates (RPIs) from yellowfin tuna roe were prepared under different solubilization and precipitation condition (pH 11/4.5, pH 11/5.5, pH 12/4.5 and pH 12/5.5). RPIs contained 2.3-5.0 % moisture, 79.1-87.8 % protein, 5.6-7. 4 % lipid and 3.0-3.8 % ash. Protein content of RPI-1 and RPI-2 precipitated at pH 4.5 and 5.5 after alkaline solubilization at pH 11, was higher than those of RPI-3 and RPI-4 after alkaline solubilization at pH 12 (P < 0.05). Lipid content (5.6-7.4 %) of RPIs was lower than that of freeze-dried concentrate (10.6 %). And leucine and lysine of RPIs were the most abundant amino acids (8.8-9.4 and 8.5-8.9 g/100 g protein, respectively). S, Na, P, K as minerals were the major elements in RPIs. SDS-PAGE of RPIs showed bands at 100, 45, 25 and 15 K. Moisture and protein contents of process water as a 2'nd byproduct were 98.9-99.0 and 1.3-1.8 %, respectively. Therefore, yellowfin tuna roe isolate could be a promising source of valuable nutrients for human food and animal feeds.

• Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.25.1-25.8
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• 2016

The fractionation of serine protease inhibitor (SPI) from fish roe extracts was carried out using polyethylene glycol-4000 (PEG4000) precipitation. The protease inhibitory activity of extracts and PEG fractions from Alaska pollock (AP), bastard halibut (BH), skipjack tuna (ST), and yellowfin tuna (YT) roes were determined against target proteases. All of the roe extracts showed inhibitory activity toward bromelain (BR), chymotrypsin (CH), trypsin (TR), papain-EDTA (PED), and alcalase (AL) as target proteases. PEG fractions, which have positive inhibitory activity and high recovery (%), were the PEG1 fraction (0-5 %, w/v) against cysteine proteases (BR and PA) and the PEG4 fraction (20-40 %, w/v) against serine proteases (CH and TR). The strongest specific inhibitory activity toward CH and TR of PEG4 fractions was AP (9278 and 1170 U/mg) followed by ST (6687 and 2064 U/mg), YT (3951 and 1536 U/mg), and BH (538 and 98 U/mg). The inhibitory activity of serine protease in extracts and PEG fractions from fish roe was stronger than that of cysteine protease toward common casein substrate. Therefore, SPI is mainly distributed in fish roe and PEG fractionation effectively isolated the SPI from fish roes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.351-361
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• 2018

This study investigated the potential of collagenous protein fractions (CPFs) as functional foods. The specific CPFs studied were recovered from the roe of bastard halibut (BH), Paralichthys olivaceus; skipjack tuna (ST), Katsuwonus pelamis; and yellowfin tuna (YT), Thunnus albacares through the alkaline solubilization process at pH 11 and 12. The buffer capacity, water-holding capacity and solubility of CPFs with pH-shift treatment were significantly better at alkaline pH (10-12) than at acidic pH (2.0). At pH-shift treatment (pH 2 and 12), the foaming capacities of CPFs from ST and YT were improved compared to those of controls, but they were unstable compared to BH CPFs. The emulsifying activity index (EAI, $m^2/g$ protein) of CPFs (controls) was 16.0-21.1 for BH, 20.1-23.9 for ST and 9.3-13.7 for YT (P<0.05). CPFs adjusted to pH 12 showed improved EAI and YT CPFs showed significantly greater emulsifying ability than those from BH and ST. CPFs recovered from fish roe are not only protein sources but also have a wide range of food functionalities, confirming the high availability of fish sausage and surimi-based products as protein or reinforcing materials for functional foods and alternative raw materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.506-519
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• 2017

This study evaluated the protein recovery and functional properties and biological activity of boiled and steamed process water (BPW and SPW, respectively) generated from the preparation of concentrated roe of bastard halibut (BH; Paralichthys olivaceus), skipjack tuna (ST; Katsuwonus pelamis), and yellowfin tuna (YT; Thunnus albacares) using the cook-dry process. The protein loss from the water extracts (EXT) of 100 g of roe protein was 15.05-19.71% and was significantly (P<0.05) higher than that of BPW (5.47-10.34%) and SPW (3.88-8.18%). The foam capacity of BPW (166-203%) and SPW (15-194%) was better than that of EXT. The emulsifying activity index of the original samples was lower than those ($15.40-107.86m^2/g$) of diluted protein samples. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and the reducing power of BPW and SPW were stronger than those of EXT. The 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid ($ABTS^+$) radical scavenging activity of EXT (0.028-0.045mg/mL) was significantly higher those of BPW and SPW. The angiotensin I-converting enzyme (ACE) inhibitory activity of SPW was the highest for BH (1.04 mg/mL), followed by YT and ST. The predominant amino acids in SPW were Glu, Ala, Leu, and His. These results demonstrate that processing water containing diluted organic components, including protein, can be consumed directly by humans as a functional reinforcing material after appropriate concentration processes.

• 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.