Processed and prepared corn products as sources of lutein and zeaxanthin: compositional variation in the food chain.

Widely consumed by populations of all socioeconomic classes worldwide, corn is one of the few food sources of lutein and zeaxanthin. However, data on these carotenoids in processed corn and corn as eaten are lacking. Thus, the major carotenoids in the principal brands of processed corn (canned corn, corn meal, corn flour, corn flake) and in typical corn dishes (farofa, boiled corn, pamonha, curau, fried and boiled polenta) were determined. There was marked variation between processed products and between brands of the same product, but variation between lots of the same brand was small. Canned corn had the highest zeaxanthin (11.91 to 18.06 microg/g), beta-cryptoxanthin (2.32 to 3.77 microg/g), and beta-carotene (1.79 to 2.75 microg/g) contents. The corn flake breakfast cereal had the second highest amount of zeaxanthin (9.08 to 12.77 microg/g). Corn meal had the highest lutein (4.02 to 7.62 microg/g) level and also had good zeaxanthin content (6.13 to 11.39 microg/g), but drastic reduction of all carotenoids, especially zeaxanthin, occurred when it was toasted to farofa. Boiled corn also had lower carotenoid levels compared to the raw corn. The wide variations in carotenoid concentrations appeared to be due mainly to varietal differences in the carotenoid composition of raw materials and to losses during processing and preparation for consumption.