Antioxidant activity of citric acid on Persian sturgeon (Acipenser persicus) fillets quality during 6 month frozen storage

In this study, the effect of antioxidant activity of citric acid (0.5%) on lipid stability in Persian sturgeon fillets (Acipenser persicus) was studied. Fish fillets were immersed in citric acid 0.5% for 5 minutes, and then packed. Samples after freezing at -40ºC kept frozen at -18ºC up to 6 months. Experiments were carried out at months 0, 1, 3 and 6 of storage on frozen fillets. Antioxidant Effect on delaying lipid oxidation was measured by free fatty acids, Peroxide value, Thiobarbituric acid test, pH and expressible moisture assessments. The rate of oxidation in Persian sturgeon frozen fillets was decreased and delayed by using Citric acid. According to experiments in the 6th month of storage rate of FFA of the Blank control was higher (18.59g oleic fatty acid kg–1 lipids) than that of in CA treatment (9.02g oleic fatty acid kg–1 lipids). Also rate of PV and TBA of the Blank control was higher (17.94 meq oxygen kg–1 lipids and 2.54 mg malondialdehyde kg–1 flesh muscle) than those of in CA treatment (10.78 meq oxygen kg–1 lipids and 1.23 mg malondialdehyde kg–1 flesh muscle). Results indicate that CA treatment, in all of lipid oxidation measuring factors had significant differences with the Blank control (P<0.05). Thus citric acid preserves quality of product during storage and it was effective on shelf life of fillets.