Stabilization of astaxanthin in edible oils and its use as an antioxidant

Astaxanthin, a ketocarotenoid (3,3′‐dihydroxy‐β,β‐carotene‐4,4′‐dione), is produced in high concentration in the green alga Haematococcus pluvialis. It constitutes 85–88% of total carotenoid and exists in the monoester, diester and free form. Astaxanthin in its ester form is fairly stable in all edible oils such as rice bran, mustard, groundnut, gingelly, coconut and palm oil at room temperature with variation in terms of its loss in content and colour during a 4 month period. Rice bran, gingelly and palm oil retained 84–90% of astaxanthin when heated at 70 °C for 8 h while palm oil was effective in retaining 90% of astaxanthin at 90 °C for 8 h without any change in its ester form in comparison to 90% carotenoid loss in aqueous form. At 120 and 150 °C, carotenoid loss was significant (60–90%) without change in the fatty acid profile of the edible oils. The antioxidant activity of carotenoids stored in oils was comparable to standard butylated hydroxy anisole (BHA). Copyright © 2007 Society of Chemical Industry