that ethanol can be used as a solvent modifier or co solvent to improve the yield of the esters the following examples show how the present invention has been practiced but they should not be construed as limiting in this application all units are in the metric system and all amounts and percentages are by weight unless otherwise expressly indicated in the examples the total carotenoid ester content was determined by spectrophotometry each sample was dissolved in hexane ethyl acetate 1 1 to form a 1 mg ml solution under sonication the solution was diluted 1 100 with hexane and the absorbance determined at 445 nm the carotenoid ester content as lutein was determined using an e1 of 1394 davies carotenoids in chemistry and biochemistry of plant pigments ed goodwin academic press london 1976 the ratio of trans cis lutein content was determined after hydrolyzing the esters and determining the area percentages of trans lutein and cis lutein by hplc marigold oleoresin containing 20 total carotenoids showing 71 trans lutein isomers and 23 cis lutein isomers by hplc area percentages was used for the studies isopropanol and ethanol were combined in different proportions v v 100 isopropanol 0 ethanol 90 isopropanol 10 ethanol 80 isopropanol 20 ethanol and 70 isopropanol 30 ethanol one hundred grams of the oleoresin was used for extraction with each solvent combination the oleoresin was mixed with 300 ml of the solvent and stirred at 23 u00b0 26 u00b0 c for four hours the precipitate was separated by vacuum filtration any leftover solution was washed with fresh solvent and the precipitate.