Process for isolation of lutein and zeaxanthin crystals from plant sources

Abstract

The present invention provides for a process for isolation of carotenoids crystals comprising drying a plant part to obtain a meal and extracting the meal with alcohol at a temperature in the range of about 50° C. to 75° C. to obtain oleoresin. The oleoresin is enriched with alcohol at a temperature in the range of about 25° C. ° C. to 50° C. and hydrolyzed with alcoholic alkali at a temperature in the range of about 70° C. to 80° C. to obtain reaction mixture. The carotenoids crystals are precipitated from the reaction mixture by adding hot water followed by filtering, washing and drying the carotenoids crystals. The present invention also relates to carotenoids crystals comprising lutein and zeaxanthin in the ratios of about 10:1 or 5:1 or 1:1 obtained by a process which comprises mixing an oleoresin rich in lutein and an oleoresin rich in zeaxanthin separately in a ratios ranging from about 80:20 (w/w) to 90:10 (w/w) or about 70:30 (w/w) to 30:70 (w/w) or about 10:90 (w/w) to 20:80 (w/w) and homogenized to obtain a mixed oleoresin. The mixed oleoresin is then hydrolyzed with an alcoholic alkali at a temperature of about 70° C. to 80° C. to obtain a reaction mixture. The carotenoids crystals are precipitated by adding hot water to the reaction mixture to form a precipitate. Carotenoids crystals having lutein and zeaxanthin in a weight ratio of about 10:1 or 5:1 or 1:1 respectively are obtained by filtering, washing and drying the precipitate.