Solubilization of vitamin C in fish oil and synergistic effect with vitamin E in retarding oxidation

Antioxidative effects of ascorbic acid and δ‐tocopherol on the oxidation of sardine oil stored at 30°C in the dark has been investigated. It was found from phase diagrams and peroxide values of fish oil/lecithin/water systems that the desirable levels of lecithin and water to solubilize ascorbic acid in the oil were 0.3% (w/w) and 0.1% (w/w), respectively. When ascorbic acid (0.02%) and δ‐tocopherol (0.4%) were used together, the induction period of fish oil could be lengthened 22‐fold, due to their synergism. They could inhibit the production of carbonyl and volatile compounds and oxidative polymerization.