Analysis of carotenoids and vitamin E in selected oilseeds, press cakes and oils

Abstract

AbstractCarotenoids and vitamin E in oils from the market – 6 rapeseed and 6 sunflower oils, half of each cold pressed and refined – and in the oils of rape, sunflower, flax and safflower as well as the respective seeds and press cakes from a local oil mill were quantified by HPLC. Furthermore, a photometric determination of carotenoid content was tested and checked against the chromatographic method. In the cold pressed oils minor amounts of xanthophylls (all‐E)‐lutein and (all‐E)‐zeaxanthin were determined. With exception of traces of (all‐E)‐β‐carotene in cold‐pressed rapeseed oil this provitamin A active compound did not occur. Cold pressed rapeseed oils contained 0.5–1.5 mg total carotenoids/100 g which was manifold the content of the further oils. Vitamin E was found in all vegetable oils at plant‐typic tocopherol patterns. The photometric determination of carotenoids resulted in significantly higher concentrations compared to the HPLC. This overestimation bases on the carotenoid pattern which was validated by comparison with known high‐carotenoid materials, i.e. maize flour with an abundant amount of xanthophylls and carrots with an abundant amount of carotenes.