Roche Vitamins Inc.

Alfred Giger

Bruno H Leuenberger

Werner Simon

Kurt Bernhard

Markus Ivo Beck

New carotenoids of the formula ##STR1## wherein R and n have the significances given herein, are useful for pigmenting the egg yolk, integuments and/or subcutaneous fat of poultry and the meat and/or integuments of fish and crustacea when included in the feed of the poultry, fish or crustacea. As well as such carotenoids and method of pigmenting the invention further embraces the pertinent carotenoid-enriched feed for poultry, fish or crustacea, the premixes for incorporation in such feeds and beadlets containing one or more of these carotenoids for incorporation in such premixes and the use of the carotenoids in the pigmenting method. The process of manufacturing such carotenoids, which more specifically may be designated as carotenoid ketones, monoesters and diesters, also represents an aspect of the invention.

Carotenoid ketones and esters

A process for the conversion of lutein or of its esters into zeaxanthin by base-catalyzed isomerization is disclosed. The process is carried out by heating an optionally pre-treated lutein-containing material in a mixture of an aqueous solution of an alkali hydroxide and either dimethyl sulphoxide or an organic solvent based on saturated aliphatic and/or aromatic hydrocarbons at temperatures in the range from about 50.degree. C. to about 120.degree. C. The process is carried out in the presence of a phase transfer catalyst when an organic solvent based on hydrocarbons is used. Being carotenoids, lutein and zeaxanthin are used correspondingly, especially as pigments for egg yolk, the integuments and the subcutaneous fat of poultry, the flesh and the integuments of fish and crustaceans, as well as foodstuffs. Zeaxanthin is preferably used in many applications, since in comparable dosages it produces a more intensive golden yellow pigmentation than lutein.

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Mohlin, Switzerland

Alfred Giger