Systematic Review of Fatty Acid Composition and the Influence of Coating Media on Fatty Acid Profiles in Canned Fish

Canned fish products enable long-term preservation of fish, a vital source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Despite research on lipid composition, gaps remain in understanding the bidirectional fatty acid (FA) exchange between fish muscle and coating media during processing and storage. After a systematic literature search across five databases (PubMed, Scopus, Web of Science, Wiley Online Library, Cochrane Library), 20 studies were included examining FA profiles across fish species, filling media (vegetable oils, brine, tomato sauce), and storage durations (up to 5 years). Five studies showed that n-3 FAs migrate from fish to the filling medium, enhancing its nutritional value, while fish muscle absorbs FAs from the oil, increasingly resembling the filling medium. The use of n-6 FA-rich oils (sunflower, soybean) lowered the n-3/n-6 ratio in flesh. Conversely, aqueous media (brine) and tomato sauce maintained better ratios. EPA and DHA content generally decreased due to canning and storage, with retention varying by fish species, filling medium, and sterilization method. This review underscores significant FA exchange between fish and filling media, confirming bidirectional lipid interchange during processing. To optimize health benefits, aqueous packing media are recommended to preserve lipid profiles or to consume the covering oil to recover nutrients. Further research is needed on other factors altering FA content in canned fish such as environmental and geographical variables (including catching season), pre-canning preparation and sterilization steps (such as freezing, steaming, and frying), sterilization conditions (time, temperature, F0 value) and lipid oxidation induced by thermal processing.