Cooking method affects lipid quality of farmed salmon
Although pan-frying is a quick and easy way to prepare palatable
foods, popular with consumers, it is also associated with undesirable
changes in the frying medium and in the fried products.
Therefore, a team from the Institute of Nutritional Sciences at
the University of Vienna in Austria investigated how different cooking
methods affected the composition of farmed salmon fillets.
Consumers are being encouraged to eat more oily fish like salmon
because they are excellent sources of the polyunsaturated fatty
acids, eicosapentaenoic (EPA) and docosahexaenoic acids (DHA).
However, being unsaturated makes them susceptible to oxidation
so Al-Saghir et al. measured the degree of lipid oxidation and the
formation of cholesterol oxidation products (COP) in salmon fillets
which had been steamed, or pan-fried with olive oil, without olive
oil, with corn oil and with partially hydrogenated vegetable oil.
The salmon samples were fried for 6 minutes with or without the
oils (3 minutes each side) or steamed for 12 minutes. Only very
small changes were observed in primary and secondary oxidation products
after cooking, and tocopherol levels also remained stable.
There were significant increases in the cholesterol oxidation products
in the fat extracted from the salmon after the various cooking procedures,
with steaming leading to the greatest increase (mainly because it
was cooked for longer).
The sum of cholesterol oxidation products increased after the heating
processes from 0.9 microg/g in the raw sample to 6.0, 4.0, 4.4,
3.3, and 9.9 microg/g extracted fat in pan-fried without oil, with
olive oil, corn oil, partially hydrogenated plant oil, and steamed,
respectively.
None of the cooking methods affected the levels of EPA and DHA
in the salmon, and the type of cooking oil also had little influence
on the outcome.
Reference
Al-Saghir S, Thurner K, Wagner KH, Frisch G, Luf W, Razzazi-Fazeli
E, Elmadfa I. (2004). Effects of different cooking procedures on
lipid quality and cholesterol oxidation of farmed salmon fish (Salmo
salar). Journal
of Agricultural and Food Chemistry, 52, 5290-5296
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