Diversität wertgebender Inhaltsstoffe bei <em>Daucus carota</em> L.

Abstract

Carrots play an important role in the human nutrition all over the world. Therefore, they have been in the focus of a varied research for a long time. The data which are presented in this study provide a comprehensive overview of the present research on carrots, new aspects of the genetic diversity of carrots and a good basis for further research projects on carrots. The content of the non-volatile compounds in carrot including carotenoids, polyacetylenes and sugars were screened in 100 genotypes of cultivated carrots and 104 genotypes of wild carrots. Carotenoids included α- and β-carotene as well as lutein and lycopene. As key compounds of the polyacetylenegroup falcarinol (FaOH), falcarindiol (FaDOH) and falcarindiol-3-acetate (FaDOH-3-acetate) were detected. All contents were calculated in milligram per 100 gram fresh weight (fw). For a better reproducibility and subsequent statistical computations of the datasets each genotype was cultivated three times and analysed twice by HPLC. For simultaneous extraction of the non-volatile carotenoids and polyacetylenes a new accelerated extraction method was developed. Using accelerated solvent extraction (ASE), 60 % to 70 % of carotenoids and polyacetylenes could be simultaneously extracted from lyophilised carrot powder during the first extraction. For this reason this newly developed extraction process linked with a fast HPLC-DAD and HPLC-MS analysis is faster and more efficient than the established methods. In the cultivated carrot genotypes α-carotene contents between 0.00 a 3.66 mg/100 g fw, β-carotene contents between 0.28 and 45.24 mg/100 g fw and lutein contents between 0.00 and 2.93 mg/100 g fw could be detected. The carotenoid contents of the mostly white coloured wild carrot genotypes vary for α-carotene between 0.00 and 4.06 mg/100 g fw, for β-carotene between 0.00 and 69.96 mg/100 g fw, for lutein between 0.00 and 8.20 mg/100 g fw and for lycopene between 0.00 and 0.54 mg/100 g fw. Significant polyacetylene contents were detected not only in wild carrot genotypes but also in the cultivated carrots. The polyacetylene contents in wild carrot genotypes for FaOH spread from 0.42 to 107.30, for FaDOH from 1.09 to 465.22 and for FaDOH-3-acetate from 0.32 to 39.96. In cultivated carrots the FaOH contents varied between 0.08 and 28.11 while the contents for FaDOH varied between 0.82 and 42.40 and for FaDOH-3-acetate between 0.16 and 14.93. A positive correlation between polyacetylenes and sucrose contents in cultivated carrots could be detected. This effect leads to the conclusion that the bitter taste in cultivated carrots is mostly masked by high sugar contents and the sweet taste. The carotenoid and polyacetylene contents in cultivated carrots are mostly influenced by the genetic background of the plant; environmental factors have only minor influence. This conclusion based on the wide-spread carotenoid and polyacetylene contents detected in 100 genotypes of cultivated carrots which were cultivated under uniform conditions. These results correspond to those from a biennial field trial conducted in Quedlinburg (Germany) and Krakow (Poland) in which 10 genotypes of cultivated carrots were analysed for their nonvolatile compounds. In this study it was found that the genetic background has the main influence on the contents of the non-volatile compounds in the carrots in contrast to the influence of the growing place. A simultaneous detection of the non-volatile compounds in the carrot leaves and roots leads to the conclusion that there are separate biosynthesis pathways for carotenoids and polyacetylenes in carrot roots and leaves. An analysis of the volatile and non-volatile compounds in the roots of 100 cultivated carrot genotypes showed that there is no correlation between volatile and non-volatile compounds in the carrot root. Therefore, a rapid test for early selection of carrot roots is not possible. Ontogenesis studies realised on two cultivated and two wild carrot genotypes confirmed the thesis that the content of carotenoids and polyacetylenes is mainly genetically controlled. An influence of cold stress on the contents of non-volatile compounds in cultivated carrots has not been found.