Inhibition of fish oil oxidation and the radical scavenging activity of New Zealand seaweed extracts

This study describes the potential use of New Zealand seaweed extracts as antioxidants in fish oils. The extracts from two brown seaweeds (Ecklonia radiata, Macrocystis pyrifera) and two red species (Champia sp. and Porphyra sp.), were added to hoki (Macruronus novaezelandiae) oil and assessed by production of oxidation products in an elevated temperature (60 °C) storage trial. Antioxidant assays ORAC and DPPH were conducted to elucidate the radical scavenging activity of the seaweed extracts. The results showed that all the lipid-soluble seaweed extracts had some antioxidative capacity, with brown algae generally outperforming red algae species. Extracts from E. radiata performed best with significantly lower primary, secondary and total oxidation products, and higher DPPH radical scavenging ability than the commercial antioxidant, BHT. This study demonstrated the potential of brown algae seaweed extracts, in particular E. radiata, for use as antioxidants in fish oil products.