Processing and storage of ratite oils affects primary oxidation status and radical scavenging ability

Abstract

Treatments for diseases such as coronary artery disease and gastrointestinal disorders seek to minimise oxidative damage by free radicals through the use of antioxidants. Oils derived from ratites (flightless birds) have therapeutic potential, with varying fatty acid composition between species. The current study investigated the influence of farm location, rendering method, duration and storage mode on radical scavenging activity (RSA) and primary oxidation status of ratite oils. Emu Oil (n = 8; EO1, EO2a/b, EO3–7; varying processing and storage factors), Ostrich Oil (OsO), Rhea Oil (RO) and olive oil (OlO) were tested for free RSA against 2,2-diphenyl-1-picryl hydracyl (expressed as 1/IC50 g/mL) and primary oxidation (peroxide mEqO2/kg). RSA (g/mL) of EO1 (558 ± 22) was greater than EO2a (8 ± 0.6), EO5 (413 ± 26), EO6 (16 ± 0.3) and EO7 (2 ± 0.2), OsO (313 ± 12), RO (32 ± 12) and OlO (196 ± 4), and less than EO3 (717 ± 32; P < 0.001). Antioxidant properties of OsO were more pronounced than RO (P < 0.001). Primary oxidation (mEqO2/kg) of EO1 (97 ± 0.6) was greater than EO2a (57 ± 0.6), EO2b (28 ± 0.2), EO5 (11 ± 0.6), OsO (50 ± 0.9) and OlO (61 ± 0.9). The wide variability in RSA of oils highlights the need for standardisation of farm location, diet composition, rendering procedures, time of render and duration of storage. Regulatory control of these parameters is recommended in order to minimise differences in therapeutic efficacy of ratite oils.