Pigment compounds were extracted from jumbo squid (Dosidicus gigas) skin with an acid‐ethanol solvent (JSE). Freeze‐dried JSE was characterized with respect to solubility in different solvents, absorption UV–VIS, and FT‐IR spectra, and tested for its radical scavenging activity against ABTS and oxygen radical absorbance capacity (ORAC). The potential ability of JSE for inhibiting oxidation of cod liver oil (CLO) was also determined by monitoring dienes, trienes, peroxide value (PV), thiobarbutiric acid (TBA), and polyene index (PI) in samples stored at 15, 25, and 50°C for 12 days. Concentrations of 0, 0.1, 0.5, 1, and 2% JSE were added to CLO. The yield of JSE was 8.8 mg/g freeze‐dried skin. Solubility behavior, UV–Vis, and FT‐IR spectra of JSE suggests that this pigment extract might belong to the ommochrome family. Moreover, a characteristic xanthommatin peak (1740 cm−1) was observed. JSE exhibited scavenging activity on ABTS•+ radical and in the ORAC assay. After storage PV and TBA increased, whereas PI decreased mainly in the control treatment. The addition of JSE delayed lipid oxidation in CLO during the first 8 days of storage at 50°C. JSE was identified as promising source of antioxidants to retard fish lipid oxidation. Practical applications: This study demonstrates that acid‐ethanol pigment extract from jumbo squid skin, which is a by‐product generated by the squid processing industries, is a valuable antioxidant source. Consistent with the preservative effect observed for this pigment extract, squid skin may be successfully employed to obtain new products for food processing and the pharmaceutical industry, with environmental sustainability benefits and provide a more effective use for jumbo squid by‐products. Acid‐ethanol pigment extracts from freeze‐dried jumbo squid skin (JSE) were added to cod liver oil and stored at 50°C. Increasing levels of JSE (0 < 0.1 < 0.5 < 1 < 2%) led to less lipid oxidation. JSE likely belongs to the ommochromes family.

This research focuses on the lipid fraction and the rancidity stability of commercial canned Atlantic Chub mackerel (Scomber colias). For it, two different concentrations of aqueous extracts of two abundant algae (Fucus spiralis and Ulva lactuca) are included in the brine‐packing (aq. 2% NaCl) medium during mackerel canning. Quality analyses are carried out after a 3‐month canned storage (20 °C). Phospholipids, sterols, and α‐tocopherol contents show a marked loss as a result of canning, this loss being mostly inhibited when considering the canned fish packed in the presence of the most concentrated algae extracts. Breakdown of free fatty acids and peroxides produced during the thermal treatment is inhibited by the presence of the algae extracts, a higher retention of such molecules being observed by increasing the algae extract concentration. Analysis of fluorescent compounds formation (tertiary lipid oxidation) shows a marked increase after canning, this increase being partly inhibited by the presence of antioxidant compounds present in the algae extracts; interestingly, oxidation inhibition is found more important in canned fish corresponding to F. spiralis batches than U. lactuca. A preservative effect on lipid constituents and rancidity development is concluded by the presence of algae extracts in the packing medium. Practical Applications: The extensive heat treatment involved during fish canning has been reported to produce breakdown of constituents, lipid damage (oxidation and hydrolysis) development showing a marked effect on nutritional and sensory properties; furthermore, this effect has shown to be greater when a brine medium is applied as packing system. Marine algae have been described as being a relevant source of chemical constituents including an antioxidant and antibacterial behavior. In the current work, employment of a commercial brine‐packing including aqueous algae extracts shows a preservative effect on the lipid fraction (composition and rancidity stability) during the canning process of Atlantic Chub mackerel. The proposed strategy may open the way to the development of a natural biopreservation for commercial canned fish due to the simple methodology employed and the abundancy of the two algae chosen for the study. Further research should envisage optimization of the preservative compounds extraction by advanced technologies. Aqueous extracts of algae Fucus spiralis and Ulva lactuca are included in the packing medium during Atlantic Chub mackerel (Scomber colias) canning. As a result, an inhibitory effect on lipid composition changes and rancidity development is obtained. Better results are observed by employing alga F. spiralis.

Summary The chemical composition of the different edible locations (central and edge muscles) of a flat fish (megrim, Lepidorhombus whiffiagonis) was comparatively analysed at both body sides. Higher moisture and lower lipid contents were obtained in central muscles than in edge ones. Edge sites showed higher triacylglycerols and sterols contents and lower mean phospholipids values than central muscles. A higher α‐tocopherol presence was observed in the lipid fraction of central muscles than in the edge ones. For both fish sides, fatty acid (FA) analysis showed lower monounsaturated FA and higher polyunsaturated FA contents and ω3/ω6 ratios in central muscles. Presence of essential elements (Co, Cu, Mn, Se, Zn) did not provide differences among sites considered. Concerning toxic elements, As content showed greater levels in central muscles than in their corresponding edge sites for both fish sides, upper zones showed higher mean scores in As, Cd, Cr, Hg, Ni, Pb and V.

This study focuses on the extraction of nutritional and healthy constituents of whole by-products resulting from the commercialisation of Patagonian squid (Doriteuthis gahi). By-products corresponding to squid individuals captured at different seasons were comparatively analysed for proximate composition, lipid classes content, fatty acid (FA) profile, and macroelement and trace element composition. As a result, moisture, lipid, protein, and ash values were included in the ranges 829.0–842.8, 17.5–21.8, 106.0–123.7, and 9.3–13.3 g·kg−1 by-products, respectively. Phospholipids showed to be the most abundant lipid class (359.2–463.5 g·kg−1 lipids), while triacylglycerols were only present in a 9.5–13.1 g·kg−1 lipids range. Valuable levels were detected for α-tocopherol (539.6–973.3 mg·kg−1 lipids), polyunsaturated fatty acids (PUFA; 50.5–52.6 g·100 g−1 FA), ω3 PUFA (47.0–48.6 g·100 g−1 FA), PUFA/saturated FA ratio (1.4–1.6), and ω3/ω6 ratio (12.1–13.4). Among macroelements, S, P, and Na showed to be more abundant than K, Mg, and Ca. Profitable levels of Co, Cu, Fe, Mn, Se, and Zn were detected in all kinds of individuals. In spite of content variations found as a result of the capture season of Patagonian squid individuals, whole by-products of this cephalopod species can be considered as a profitable source to provide the food and pharmaceutical industries with useful value-added constituents.

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