Dsm IP Assets B.v.

Roche Vitamins Inc.

Arnold Gloor

Werner Simon

Hansjoerg Gruendler

The invention relates to a process for the purification of riboflavin comprising the steps of (a) precipitating a first crystalline form of riboflavin, (b) isolating the first crystalline form of riboflavin, (c) transforming the first crystalline form of riboflavin into a second crystalline form of riboflavin under conditions that decompose diluted DNA, and (d) isolating the second crystalline form of riboflavin, provided that at ambient temperature the first crystalline form of riboflavin is thermodynamically less stable than the second crystalline form of riboflavin.

Process for the purification of riboflavin

Astaxanthin derivatives of the general formula (I) wherein R is in each case group &#x2014;NH&#x2014;CH(R)&#x2014;COOR, &#x2014;ORor &#x2014;(Y)-Z and R, R, R, Y, Z and n are significances given in detail in the description, are novel compounds with improved stability during extrusion at the elevated temperatures as required in feed manufacture and during the storage of the manufactured feed and which accordingly are useful as pigmenting carotinoids for feed for aquatic animals. The derivatives are produced by reacting astaxanthin with the pertinent acid RCOOH as such or as its acid chloride RCOC1 or acid anhydride (RCO)O, or, in the cases where R signifies a group &#x2014;NH&#x2014;CH(R)&#x2014;COOR, with the appropriate N-carbonyl-amino acid ester of the formula OCNCH(R)COOR. The invention also concerns a formulation containing such an astaxanthin derivative as the pigmenting carotenoid for use in a feed for aquatic animals, a process for producing such a formulation by dissolving the astaxanthin derivative in a plant or vegetable oil or fat, or in an organic solvent, or in a mixture of both a plant or vegetable oil or fat and an organic solvent, emulsifying the solution with an aqueous solution of a protective colloid, at least partially removing the solvent and water to afford a concentrated emulsion, and spray-drying the concentrated emulsion to finally produce a formulation suitable for incorporation in a feed for aquatic animals, and a feed for aquatic animals containing such a pigmenting carotenoid. 

Astaxanthin esters

A process for catalytically isomerizing Z-3-methylpent-2-en-4-yn-1-ol to E-3-methylpent-2-en-4-yn-1-ol is provided. This process includes contacting a stereoisomeric mixture containing Z-3-methylpent-2-en-4-yn-1-ol and E-3-methylpent-2-en-4-yn-1-ol with a source of bromine radicals in a two-phase reaction mixture having an aqueous phase and a stereoisomeric mixture phase, intermixing the reaction mixture, and heating the reaction mixture to a temperature from about &minus;10&deg; C. to about 100&deg; C.

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Basel, Switzerland

Arnold Gloor