Journal of Aquatic Food Product Technology 2019, VOL. 28, NO. 2, pp. 165–176
Freshwater fishes contain long chain omega-3 and omega-6 polyunsaturated
fatty acids (PUFAs) of highest nutritional value. PUFAs in fish are susceptible to
oxidative damage during processing and subsequent storage. Sardines
(Rastrineobola argentea) are an important fish species of Lake Victoria, constitut-
ing 72.3% of the total landings by weight on the Tanzanian side of the lake. Fatty
acid profiles and lipid oxidation status of sun-dried, deep-fried, and smoked
sardines were investigated. Lipid oxidation was assessed by peroxide value,
thiobarbituric acid reactive substances (TBARS), and free fatty acids. Fatty acids
were analyzed by gas chromatography with flame ionization detector. The three
omega-3 PUFAs: docosahexaenoic acid (C22:6n-3), docosapentaenoic acid
(C22:5n-3), and eicosapentaenoic acid (C20: 5n-3) contributed 57–60, 63, and
38% of PUFAs in sun-dried, smoked, and deep-fried sardines, respectively. Lipid
oxidation reactions were more pronounced in sardines dried on sand and rocks,
with TBARS values 97.87 and 84.18 μmolMDA/kg, respectively. The polyene
index was significantly lower (p < 0.05) in deep-fried sardines, indicating lower
retention of PUFAs in the product. Lake Victoria sardines are a rich source of
omega-3 PUFAs. PUFAs in sun-dried sardines are prone to oxidative damage.
Smoking resulted in relatively higher retention of omega-3 fatty acids in
products.