A comparison of the levels of lutein and zeaxanthin in corn germ oil, corn fiber oil and corn kernel oil

Authors: Moreau, Robert; Johnston, David; Hicks, Kevin

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/5/2007
Publication Date: 10/9/2007
Citation: Moreau, R.A., Johnston, D., Hicks, K.B. 2007. A comparison of the levels of lutein and zeaxanthin in corn germ oil, corn fiber oil and corn kernel oil. Journal of the American Oil Chemists' Society 84:1039-1044.

Interpretive Summary: Kernels of yellow corn contain high levels of lutein and zeaxanthin, two carotenoids that have been shown to be beneficial for the treatment of age related macular degeneration and other health problems. However, commercial corn oil, obtained from corn germ by pressing and/or hexane extraction, contains only trace levels of carotenoids. The results from the current report indicate that a new type of corn oil can be produced by extracting ground corn with ethanol. This new corn oil has an amber color because it contains high levels of lutein and zeaxanthin. If a suitable gentle refining method can be identified and shown to retain most of the carotenoids in the oil, a diet that includes 30 g (~2 tbs)/day of this type of ethanol-extracted corn oil will provide ~6 mg of lutein + zeaxanthin, the daily dosage that is currently considered to be necessary to slow the progression of age-related macular degeneration. This information will be useful to corn oil refiners, nutritional researchers, and new product developers, who are creating natural and health-promoting foods and nutraceuticals for an aging population in the US.

Technical Abstract: All commercial corn oil is obtained by pressing corn germ and/or extracting germ with hexane. In the current study, six types of corn oil were prepared by extracting corn germ, corn fiber and ground whole corn kernels, each with hexane or with ethanol. The levels of lutein, zeaxanthin and other carotenoids were quantitatively analyzed in the six corn oils. The levels of lutein + zeaxanthin ranged from about 2 µg/g for hexane extracted corn germ oil to 220 µg/g for ethanol extracted ground corn oil. These results indicate that if a suitable gentle refining method can be identified that can retain most of the carotenoids in the oil, a diet that includes 30 g (~2 tbs)/day of corn oil obtained by extracting ground corn with ethanol will provide ~6 mg of lutein + zeaxanthin, the daily dosage that is currently considered to be necessary to slow the progression of age-related macular degeneration.