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Food component characteristics of tuna livers

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Abstract

Livers of skipjack tuna (Katsuwonus pelamis) and yellowfrn tuna (Thunnus albacares) were investigated on the food compositional characteristics and also compared to that of Alaska pollack (Theragra chalcogramma). The proximate compositions of skipjack tuna and yellowfrn tuna livers were high in crude protein, carbohydrate, and crude ash, while were low in crude lipid when compared to that of Alaska pollack liver. The results of heavy metal suggested that tuna livers appeared safe as a food resource. The total amino acid contents of skipjack tuna and yellowfrn tuna livers were 17.7 and 17.1 g/100 g, respectively, and the major amino acids in both livers were aspartic acid, glutamic acid, alanine, valine, leucine, and lysine. Tuna livers were good sources of iron and zinc, while have low lipid content. The extractive nitrogen contents of skipjack tuna and yellowfrn tuna livers were 526.5 and 468.2 mg/100 g, respectively, and their major free amino acids were taurine, glutamic acid, and alanine. From the results of taste value, the major taste active compounds among free amino acids were glutamic acid and aspartic acid.
... , , . (Heu et al., 2006;Kang et al., 2007;Kang et al., 2015;Kim et al., 2015;Lee et al., 2016b;Yoon et al., 2017). ( Lee et al., 2016a), (Heu et al., 2010;Lee et al., 2016b), Yoon et al., 2017) , (Lee et al., 2016a;Binsi et al., 2017;Yoon et al., 2018b), (Lee et al., 2016c), (Noh et al., 2013;Intarasirisawat et al., 2014) (Park et al., 2016;Binsi et al., 2017;Yoon et al., 2018b), (Heu et al., 2009;Intarasirisawat et al., 2014) . ...
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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 emulsi-fying 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.
... . , (Heu et al., 2006;Kang et al., 2007;Kang et al., 2015;Kim et al., 2015;Lee et al., 2016). ...
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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.
... In addition, antioxidant peptides derived from aquatic products and by-products such as mackerel protein, jumbo squid skin, yellowfin sole frame protein, hoki frame protein, and Alaska pollack frame protein have also been reported (Wu et al., 2003; Jun et al., 2004; Je et al., 2005; Mendis et al., 2005; Kim et al., 2007). In Korea, the annual catch of skipjack tuna has increased as this tuna is the primarily used raw material for canned tuna production, a consumerfriendly seafood product, and the total catch was recorded as 171 641 M ⁄ T in 2005 (Kang et al., 2007). ...
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