The effect of different methods on fatty acid composition of Tilapia, Oreochromis niloticus, fillets

Tilapia, a perch fish from Cichlidae family has witnessed a vast and fast growth in artificial
culture due to simple and inexpensive procedures for the practice. One of the most important
farm species is considered to be the Nile Tilapia (Oreochromis niloticus). The effects of
different cooking methods on fatty acid composition and nutritional value of Tilapia fish fillet
were evaluated. The cooking methods included: Red off, microwave, oven cooking, barbecue,
boiled water and raw treatment. The protein content was assessed using the Kjeldahl method,
moisture was evaluated through dry method, fat and ash through Soxhlet and electric furnace
methods. To measure the composition of fatty acids, Gas-chromatography method (GC) was
applied, and the Bligh and Dyer method of extraction and identification of fatty acids was
implemented. The results showed that applying different curing methods caused moisture loss
of 1-9%, 2-12% increase in protein content, fat reduction of 0.2-4.2% (excluding the red off
treatment in which fat increased by about 0.5%), increase in ash of 0.7-0.15%, reduction of
Mono Unsaturated Fatty Acids between 1-6% and increase in Poly Unsaturated Fatty Acids
between 0.5-14%. The rate of saturated fatty acids showed an increase of 0.6-1.6% in all
treatments with the exception of baking and red off treatments. The results indicated the
lowest change (about 0.2%) in EPA, in the microwave and grilled fillet treatments and the
highest change (0.7%) in the red off fillets compared to raw samples. The minimum change in
DHA was observed in the oven-cooked fillets (0.45%) and the maximum change (2.5%) in
the red off fillets. The highest EPA and DHA were found as 1.33 and 3.32% in samples
cooked in oven. Results showed that the ratio of 6/ 3 increased in the red off samples
compared to other treatments.
*Corresponding author