Comparative study on nutrient compositions of kutum (rutilus frisii kutum) and grass carp (Ctenopharyngodon idella) and their marinade qualities

The Caspian kutum, Rutilus frisii kutum, and grass carp, Ctenopharyngodon idella are two commercially important fishes with similar external features, the first one being endemic to the Caspian Sea, and the second one is cultured in freshwater polyculture system. In this study the nutrient composition of these fishes were compared. Then with the intention of better shelf-life, their hot processed marinades were organoleptically analysed at intervals of 2, 4, 6 and 8 months, using Total Volatile Nitrogen (T.V.N) and peroxid values. The comparison of the fish composition with Duncan test showed no significant difference (p< %5) in average amount of protein, ash and energy content, but significant difference in amount of lipid, P, Ca content, iodine value, saponification value, acid value, peroxide value (at 0,1,3,5 and 7 days after oil extraction) was observed. It means that lipid content, peroxide value and acid value in kutum were higher than grass carp (0.93%, 1.5 mEq/kg and 4.33% fatty acid according to oleic acid, respectively), and Ca, P contents, iodine value and saponification value, on the other hand, were higher in grass carp (39.89 and 12.01 mg/100g , 6.20 %12 and 8.62 mgKOH/g, respectively). The organoleptic results showed that the produced marinade from grass carp (according to variance analysis) is perferable than the other one. Also, it was found that this marinade can be stored during 6 months at 10°C in good condition