Effects of enzymatic treatments of marigold flowers on lutein isomeric profiles

Reversed-phase C-30 HPLC was applied to study the identity of lutein isomers and to monitor the effects of solids content and elimination of water-soluble substances on the isomeric carotenoid profiles of marigold (Tagetes erecta) samples treated with enzymes. The tentative identity of four lutein isomers present in saponified marigold extracts was confirmed. Enzymatic treatment on a 5% solids slurry produced the marigold meal with the highest all-trans-lutein content [25.1 g/kg dry weight(dw)]. We did not observe variations in the distribution in percentage of lutein isomers due to enzymatic treatment; the elimination of water solubles had a significant but small effect on such variations. The solids content was the principal factor that affected the carotenoid profiles. An analysis of the distribution showed that 15% solids gave the highest all-trans-lutein percentage in treated meals. Interestingly, with 20% solids both the degradation of lutein and the percentage of all-trans-zeaxanthin were the highest.