Rancidity development during the chilled storage of farmed Coho salmon (Oncorhynchus kisutch)Coho salmon (Oncorhynchus kisutch) is a fatty fish species whose farming production has greatly increased in recent years. Lipid damage produced during Coho salmon chilled storage was studied for up to 24 d. Lipid hydrolysis (free fatty acids, FFA) and oxidation (conjugated dienes; peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescent compounds formation, FR; browning development) were determined and compared to lipid composition (polyene index, PI; astaxanthin, AX) changes and sensory assessment (rancid odour development) results. Most lipid damage indices developed slowly during storage; thus, values obtained for FFA, PV, TBA-i and FR were in all cases under 1.5 g/100 g, 4.0 meq oxygen/kg lipid, 0.40 mg malondialdehyde/kg muscle and 0.40, respectively. Odour assessment showed a significant (p ,0.05) rancidity development at day 10, when compared to starting fish material; then, nonacceptable values were obtained at days 19 and 24. The PI analysis showed not many differences during the storage time, with the lowest mean value at day 19. AX analysis indicated a relatively high content in the white muscle, which was maintained till the end of the experiment. A low oxidation development is concluded for Coho salmon lipids when compared to other fatty fish species under the same chilling conditions. AX was found to contribute to the oxidation stability of Coho salmon lipids, due to its free radical scavenger properties.

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Lipid changes related to quality loss were evaluated during frozen storage of coho salmon for up to 15 months. Biochemical indices concerning lipid hydrolysis (free fatty acids, FFA) and oxidation (peroxide value, PV; thiobarbituric acid index, TBA-i; fluorescent compounds, FR; polyene index, PI) were determined and compared to sensory (odor and taste) and endogenous antioxidant (tocopherol isomers and astaxanthin) assessments. As a result of the frozen storage, lipid hydrolysis was shown to develop according to the increase in FFA content (p < 0.05). However, most biochemical lipid oxidation indices (PV, TBA-i and FR) led to a low degree of rancidity development (p < 0.05) when compared to other fatty fish species under similar frozen storage conditions. The PI value decreased (p < 0.05) at month 10 but then remained unchanged until the end of the experiment. Rancid odor and taste development were shown to be low throughout the experiment, according to the biochemical indices mentioned above. However, a progressive decrease (p < 0.05) in the original fresh odor and taste of salmon fish flesh occurred with increasing frozen storage time, such that fish samples had the poorest scores by month 15. Endogenous antioxidants were remarkably stable throughout the experiment and which might contribute to the oxidative stability of frozen farmed coho salmon lipids.

Artículo de publicación ISICoho salmon (Oncorhynchus kisutch) supports an important farming production in parallel with capture delivery, giving rise to products of great economic importance in many countries. This review covers the research carried out during the last decades related to its employment as a food product. In the first part, studies carried out concerning the chemical constituent composition and nutritional value are reviewed; special attention is accorded to the wild/farmed fish comparison and to the effect of diet on lipid composition variations. In agreement to the great lability of chemical constituents of aquatic foods, the second part of the manuscript provides a revision of coho salmon research related to the chemical component changes produced during technological processing and their effects on nutritional and sensory losses; in this case, special attention is accorded to studies employing advanced technological strategies focused to partially inhibit the development of the different damage pathways.Universidad de Chile (Chile)–Consejo Superior de Investigaciones Científicas (CSIC, Spain) research program through the following projects: Project 2003 CL 0013, Project 2004 CL 0038 and Project 2006 CL 0034

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