Patent ID: 7271298
Filing Date: 2007-09-18
Classification: C07C

Abstract:
1. A process for preparing xanthophylls comprising the steps of: a). saponifying a homogeneous liquid mixture of a xanthophyll diester-containing plant oleoresin and an alcohol by adding an aqueous alkali solution to the mixture and mixing at a temperature in the range of 40 to 85° C. for 3-5 hours, wherein a ratio of the weight of the alkali in the aqueous alkali solution to that of the plant oleoresin is about 1:8 to 3:1; b). cooling the saponified reaction mixture to an ambient temperature, and adjusting its pH to 1-7; c). admixing 2 to 10 volumes of water and 0.5 to 2 volumes of the alcohol per weight of the plant oleoresin with the cooled mixture, increasing the temperature to 40° C. to 85° C., and agitating slowly for a period of 0.5 to 2.0 hours to form crystalline precipitate; d). separating and recovering xanthophyll crystals from the crystalline precipitate; e). washing the xanthophyll crystals 2-3 times with water at a temperature of 70-85° C. until supernatant is colorless; and f). leaching the xanthophyll crystals with dry ethanol and drying the xanthophyll crystals to less than 5% moisture content.