Effects of antioxidants on copper induced lipid oxidation during salting of cod (Gadus morhua L.)

Abstract

A model system for studying lipid oxidation of salted cod muscle was used for investigating the interaction effects of including antioxidants and copper in the brine. The results showed that ascorbate might have pro-oxidative or anti-oxidative effects depending on the ascorbate and metal concentrations. Without added copper in the brine, concentrations of ascorbate ≤500 ppm had a pro-oxidative effect. With 5 ppm copper added in the brine, low concentrations of ascorbate (≤50 ppm) inhibited the formation of TBARS in the cured product. At slightly higher concentrations (100-200 ppm), the anti-oxidative properties were lost. Above 200 ppm the ascorbate reduced the oxidation level in the salt ripened product. The application of ascorbate as an antioxidant in salt curing of cod, requires the use of high concentrations (≥1000 ppm) in the brine. When similar concentrations (0.5 mM) of EDTA, citrate or ascorbate were included with 3 ppm copper in the brine, EDTA was the only antioxidant that efficiently inhibited copper-induced lipid oxidation.