Starfish oil as a sustainable new source of marine oil: Composition and stability

The estimated requirements for marine oils for human consumption and aquaculture are higher than current production volumes from industrial fisheries. New raw materials or better utilization of existing ones must be implemented to meet estimated requirements, if the fisheries are to be sustainable. Currently, starfish is an underutilized raw material. Analysis of the composition of starfish oil reveals that starfish can be a new source of marine n-3 PUFA oil. Starfish oil contains EPA and DHA both in the form of triglycerides and phospholipids. Moreover, the oil contains pigments such as astaxanthin. Because of the highly unsaturated nature of starfish oil, it is susceptible to lipid oxidation.

Therefore, this study evaluated different approaches to improve the oxidative status of the starfish meal before oil extraction and oxidative stability of the oil using antioxidants. The work was divided into three parts: 1) Oxidative stability of extracted oil (Oxipress, storage) with and without antioxidant addition where starfish oil was extracted using supercritical CO₂ extraction with ethanol as co-solvent 2) Effect of storage (time, temperature) from harvest to drying and 3) Effect of antioxidant addition to starfish before drying on the oxidative status of the meal.

Results showed that the oxidative stability was lower for unrefined starfish oil compared to high quality krill and cod liver oils. Some antioxidant blends improved the oxidative stability measured by either a longer induction period using Oxipress or lower formation of PV and volatiles during storage. However, the initial oxidative status of the starfish oil was low. The oil quality of the meal seemed to be affected by the storage of the starfish from harvesting to drying, where higher temperature and longer storage time reduced the quality. Additionally, the addition of different antioxidant blends to the starfish before drying reduced the concentration of hydroperoxides in the meal.