Changes of amino acid contents of common carp (Cyprinus carpio) fillets during 6 months of frozen storage at -18°C

The aim of this research was to study the effect of the storage temperature on common carp (C. carpio) fillet’s nutritional value in a 6 months period at -18°C. Fresh carps were bought from a local aquaculture farm in Babolsar (Gilan Province, Iran) and immediately transported to laboratory and then fillets were prepared, frozen and stored at -18°C for the mentioned period; Analyses of the protein, fat, ash, moisture, TVN and amino acid contents were performed at days 0, 30, 60, 90, 120, 150 and 180; Results for the fresh to 180 days stored fillets showed 16.20/14.10% protein, 4.10/2.02% fat, 1.01/1.08 ash, 78.69/77.30 % moisture and 11.2/14.26 mg/100g TVN contents. Also it was revealed that 17 amino acids (9 essential or EAA and 8 nonessential or NE) were present in the fillets with maximum content for glutamic acid and minimum for cysteine. Total amount of EAA and NE of the fresh fillets were determined to be 77.35 and 70.40 mg/100 g, respectively, (Fresh Fillets EAA/NE ratio= 1.09) which decreased to 61.13 for EAA (P0.05) and 61.85 for NE (P0.05) at the end of the period (180 days stored Fillets EAA/NE ratio= 0.988). In conclusion, it should be declared that changes of essential amino acid contents and total volatile nitrogen, protein and fat contents were significant.