Curcumin and its two analogues improve oxidative stability of fish oil under long‐term storage

Abstract

Adding antioxidant is one of the most effective ways to prevent oil systems from oxidation. Curcumin (Cur) and its derivatives have a significant antioxidant activity as potential antioxidants. In this work, the oxidative stability of fish oil treated with three different concentrations (0.1, 0.2 and 0.3 mg/g) of Cur, its two synthetic analogues (compounds 14 and 25) and α‐tocopherol (positive control) are determined after 70 days at 4 and 25 °C. The antioxidants are evaluated by acid (AV), peroxide (PV), conjugated diene (CD) values, thiobarbituric acid‐reactive substances (TBARS) as well as polyunsaturated fatty acid (PUFA) in fish oil. Results show that Cur and α‐tocopherol could protect fish oil from oxidation more effectively than compound 14 and 25 at 4 °C, whereas compound 14 and 25 could protect fish oil from oxidation more effectively than Cur and α‐tocopherol at 25 °C. Temperature is an important factor on lipid oxidation in the process of fish oil storage resulted from antioxidant activity of compounds determined by temperature. Curcumin shows the decreased ability to protect fish oil from oxidation with increasing temperature. Compounds 14 and 25 show increasing ability to protect fish oil from oxidation with increasing temperature.Practical applications: Compounds 14 and 25 are potential antioxidants to extend expiration date of the fish oil product.Temperature is a key variable for fish oil storage. Compounds 14 and 25 show higher biological stability than that of Curcumin. In long‐term storage at 25 °C, compounds 14 and 25 perform better antioxidant activity in fish oil than Curcumin, and tocopherol.