Identification of fatty acids composition in fresh and frozen silver carp (Hypophthalmichthys molitrix) for determination of its shelf life at -18c

In this work, after extraction and methylation of the lipids form silver carp tissues in fresh and frozen stages and their changes during 6 months in -18°C, identification of fatty acids of the samples were done by gas chromatography (Shymatsv HSSA4). Results of this investigation showed that amounts of unsaturated and saturated fatty acids in fresh samples were 70/95% and 28/95% respectively. In fresh tissues the amount of oleic acid was 30/16%, and Iino leice amount was 11/44%. Alpfa – lino lenice acide was 4/41%, Gcosapanethanoic was 6/42% and docosa hexanoic was 6/15%. These were the most important poly-saturated fatty acids. But after six months of freezing at -18° c the amounts of these fatty acids decreased to 10/02%, 3/18%, 2/97%, 1/05% and 1/02% respectively. Results showed a decrease in freezing condition of fatty acids. Based on these results, the best storage for frozen fish in -18°C is four months. These results were subjected to tests of Tukey and Analysis of Variance and were significant at the level of 95%.