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Kemijski inštitut, Ljubljana (KILJ)
  • Determination of all-trans-lutein in spinach
    Simonovska, Breda ; Černelič, Katarina ; Vovk, Irena, 1965-
    The aim of our work was to find the optimum conditions for determination of lutein in lyophilised spinach sample using nontoxic toxic solvents and miniaturised and simple preparation of the test ... solution. We were also interested in influence of addition of antioxidants during the preparation of test solution and extraction in air or in nitrogen atrnosphere. Extraction of 10 mg of Iyophilized and powdered plant material with 10 ml of ethanol with magnetic stirring for one hour at room temperature in tubes gave a satisfactory test solution after centrlfugatlon. Two replicates of sample test solutions. two replicates of standard solutions and two replicates of spiked test solution with the same concentration of standard were simultaneously prepared. The same procedure was repeated with addition of 10 mg of antioxidants butylated hydroxytoluene (BHT) or tertbutylhydroqulnone (TBHQ) to all standard solutions, extracts and spiked extracts. The whole experlment with magnetic stirring of solutions of standards, extracts of spinach and spiked extracts was performed in air and under nitrogen. Absorbances of standard solutions at 445 nm before and after the stirring were measured and served for the determination of the concentration of lutein in standard solutions, taking the published value 2550 as specific absorption coefficient at 445 nm. HPLC determination of all-trans-lutein was performed on Prontosil C30 column, 250 x 4.6 mm, with 5 [nu]m partldes. Gradient of acetone-water was used for the separation of compounds. The eluted compounds were detected by PDA. For the calculation of the content of lutein in lyophilised spinach sample and determination of % recovery, standard treated in the same way as samples was taken. Extraction in nitrogen gave significantly higher values for the content of lutein in spinach compared to the extraction in air (about 10%), but the influence of antioxidants was not significant. Recovery was dose to 100% at extractlon in nitrogen, but lower in air, which means that lutein in the mixiure with other compounds in the spinach extract was more susceptible to degradation than in standard solution during stirring. The results were verifled on the certifled material for the determination of carotenoids.
    Vir: 16th International Symposium on Carotenoids : 17-22 July 2011, Krakow, Poland : abstracts : Towards a Brighter Side of Life (Str. 62-63)
    Vrsta gradiva - prispevek na konferenci ; neleposlovje za odrasle
    Leto - 2011
    Jezik - angleški
    COBISS.SI-ID - 4760346

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