engleski

Carotenoids in some Mediterranean foodstuffs: HPLC- TLS studies

The nutritional importance of certain carotenoids as metabolic precursors of vitamin A is well known. Additional functions of carotenoids, including some non-provitamin ones, have been suggested to include cancer prevention, immunoenhancing activity, and acting as antioxidants in vivo. Hyphenation of a non-aqueous reversed-phase HPLC and highly sensitive thermal lens detection (HPLC-TLS) enabled the determination of some carotenoids at ultratrace levels, namely from the samples which were multifold diluted prior to analysis. In summing up our results obtained by the analyses of some foodstuffs by HPLC-TLS, typical carotenoid patterns may be suggested. For example, chromatograms of sesame and olive oils indicated the presence of early eluting lutein and alpha- carotene (in the sesame oil), followed by both trans- and cis-isomers of beta-carotene. In tomato purée extracts, initially eluting xanthophylls were followed by alpha-carotene, trans- and cis- beta-carotene and lycopene isomers. As far as total carotenes are concerned, HPLC-TLS enabled detection of concentrations as low as 1.4 ng/mL in tomato purée extracts and down to 1.5 ng/mL in diluted oils. Concentration of total carotenes did not exceed 0.2 and 2.6 microgram/mL in sesame and olive oils, respectively. HPLC-TLS helped in getting an insight into characteristic carotenoid/carotene pattern of some typical Mediterranean foodstuffs.

carotenoids; olive oil; sesame oil; tomato puree; HPLC-TLS

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