Astaxanthin improved the storage stability of docosahexaenoic acid-enriched eggs by inhibiting oxidation of non-esterified poly-unsaturated fatty acids.

This study assessed the potential and mechanism of action of astaxanthin, to improve the stability of docosahexaenoic acid (22:6(n-3); DHA) enriched egg products, during storage at 4 °C. The reduction in DHA content after 42 days of storage in astaxanthin-DHA eggs (from hens fed supplemental astaxanthin and DHA) was <3%, whereas the reduction in regular-DHA eggs (hens fed DHA only) was over 17%. Astaxanthin also decreased production of oxidation products including 4-hydroxy-2-hexenal, 4-hydroxy-2-nonenal and malondialdehyde in eggs during storage, thus markedly improving the oxidative stability of DHA-enriched eggs. The yolk lipidomic profile showed higher intensities for most DHA-containing lipids, especially DHA-phosphatidylcholine, DHA-phosphatidylethanolamine and DHA-non-esterified fatty acid, compared with regular-DHA eggs. Astaxanthin acts primarily by suppressing oxidation of DHA-non-esterified fatty acid, which minimizes the degradation of DHA and appears to be the primary protection mode of yolk DHA during storage.