Separation and identification of the yellow carotenoids in Potamogeton crispus L.

It was found that ducks fed with Potamogeton crispus L. could lay natural red-yolk eggs with good quality in vast lake areas. P. crispus L. was found to be a new resource of carotenoids based on this fact. Carotenoids from P. crispus L. were extracted using petroleum ether-acetone and saponified using 40% methanolic potassium hydroxide. Four major yellow carotenoid pigments were obtained by a MgO column and thin-layer chromatography. These carotenoids were identified as neoxanthin, violaxanthin, lutein and β-carotene based on visible spectra in different solvents compared with values reported in the literature, functional group tests and mass spectrum by LC-MS. The content of total carotenoids from P. crispus L. was measured to be 231 μg/g (dry weight) by visible absorption spectroscopy.