Preparation of the red yeast, Xanthophyllomyces dendrorhous, as feed additive with increased availability of astaxanthin.

Xanthophyllomyces dendrorhous (Phaffia rhodozyma) is used as a colorant for aquaculture, egg yolks, and crustaceans but its carotenoids can only be absorbed by animals when its cell wall is degraded. Conditions that degraded the cell wall of X. dendrorhous were developed. To measure the degrees of cell wall degradation, the carotenoid extractability (extracted carotenoid by acetone/total carotenoid) unit was used. Treatment with HCl (0.2 M, 9 h, 90 degrees C) followed by neutralization to pH 3 by NaOH and spray-drying increased carotenoid extractability to 100% with minimal decomposition.