Abstract: The use of ?-zeacarotene, ?-zeacarotene or a mixture of both as a coloring agent for food or pharmaceutical compositions. For addition to the food or pharmaceutical composition or otherwise incorporation therein during its preparation the zeacarotene (mixture) is generally first formulated to a solid or liquid colorant composition in the form of a stable water-soluble or -dispersible powder, an aqueous colloidal solution or oil-in-water dispersion of such powder, an oil-in-water dispersion of the zeacarotene (mixture), or an oil-soluble dispersion of the zeacarotene (mixture) in a triglyceride. In a solid colorant composition the zeacarotene (mixture) is generally finely dispersed in a matrix or carrier.

Abstract: 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.

Abstract: 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.