Antioxidative capacity of microalgal carotenoids for stabilizing n-3 LC-PUFA rich oil: Initial quantity is key

The health-beneficial long-chain omega-3 polyunsaturated fatty acids (n-3 LC-PUFA) are easily affected by the undesired process of lipid oxidation in fish oil, while being stable in the lipid extracts of photoautotrophic microalgae. The current research investigates the role of carotenoids by evaluating the oxidative stability of mixtures of fish oil with total lipid extracts of two different microalgae (Phaeodactylum and Isochrysis) throughout an accelerated storage experiment of 4 weeks at 37 degrees C. A clear separation between oxidatively stable and oxidatively unstable mixtures was observed for which the initial amount of carotenoids relative to the amount of n-3 LC-PUFA was a good indicator. The lipid class composition, clearly differing between the two algae, was probably of minor influence. The antioxidative role of fucoxanthin, and diatoxanthin and beta-carotene as minor carotenoids, was illustrated by their gradual degradation throughout storage. However, when their initial con-tents were too low, this role could not be exerted leading to thorough lipid oxidation.

Automated summary

This research investigates the role of carotenoids in the oxidative stability of mixtures of fish oil and lipid extracts of two different microalgae. It finds that the initial amount of carotenoids relative to n-3 LC-PUFA is a good indicator to differentiate between oxidatively stable and unstable mixtures. The degradation of fucoxanthin, diatoxanthin, and beta-carotene during storage illustrates their antioxidative role.