Effect of Frozen Storage Time on the Lipid Deterioration and Protein Denaturation During Caspian Sea White Fish (Rutilus frisi kutum)

COMPARATIVE STUDIES ON EFFECTS OF FREEZING ON PHYSICOCHEMICAL PROPERTIES OF FILLETS TWO FISH SPECIES IN IRAN

Because of fishes Sparidentex hasta and Pampus argenteus in the southern of Iran are consumed abundant in a particular season and it should be frozen for consumption throughout the year. Therefore, this research was carried out to investigate the effects of freezing on some of the physicochemical properties of fillets the fishes. Factors such as fat with chloroform-methanol method, amount of TBA (Thiobarbituric acid) in fish muscle accordance method of Pearson, pH using a pH meter, FFA (Free fatty acids) with titration in the presence of phenolphthalein was determined based on the percentage of oleic acid, peroxide value according to AOAC (Association of Official Analytical Chemists), in fresh samples at time zero and after different periods of freezing were tested respectively. Result showd that TBA (Thiobarbituric acid) content in fish fillet, found Pampus argenteus and Sparidentex hasta 0.65 and 0.53 respectively. The results showed that the highest percentage of fat found for Pampus argenteus at 95 days 24.2(%2) and for Sparidentex hasta at 35 days (25.19%), free fatty acids contents found highest (0.9%) and (0.97%) for Sparidentex hasta and Pampus argenteus after 95 days. It can conclude that the TBA (Thiobarbituric acid), FFA (Free fatty acids)  contents and pH of both fish species during storage in freezer were increased. Peroxide value in fish Pampus argenteus was reduced but, in Sparidentex hasta showed no significant differently.  The best time of storage of fishes Pampus argenteus and Sparidentex hasta at -18 °C was 35 days freezing, but nutritional value of fillets and fatty acids greatly reduced