Effects of cultivation conditions and cold storage on polyacetylene contents of carrot (Daucus carota L.) and parsnips (Pastinaca sativa L.)
Polyacetylenes are a class of highly bioactive compounds which may negatively affect the sensory properties of Apiaceous plants such as carrots and parsnips. In the present study, the effects of organic nitrogen fertilisation, water supply, and cold storage on the contents of falcarinol (FaOH), falcarindiol (FaDOH), and falcarindiol-3-acetate (FaDOAc) were investigated in four carrot (Daucus carota L.) and two parsnip (Pastinaca sativa L.) cultivars. Relatively high contents of polyacetylenes were observed at an early developmental stage of the roots of both carrot and parsnip, decreasing to a transient minimum approx. 1 month prior to harvest maturity.The supply of super-optimal levels of nitrogen (50 or 100 kg N ha–1) using organic fertiliser did not significantly affect the polyacetylene contents of carrot or parsnip at harvest (except FaDOH contents in ‘Rodelika’ carrot). Different levels of water supply to potgrown carrots in climate chambers induced complex, cultivar-dependent, and apparently development-dependent patterns of change in polyacetylene contents and profiles. Cold storage of field-grown ‘Bolero F1’ and ‘Rodelika’ carrot significantly increased the levels of individual polyacetylenes in both cultivars. However, carrots previously supplied with super-optimal amounts of nitrogen fertiliser (50 or 100 kg N ha–1) either showed a transient increase (‘Bolero F1’) or a transient decline (‘Rodelika’) in polyacetylene contents during cold storage. The results suggest active pre- and post-harvest synthesis and metabolism of polyacetylenes in carrot and parsnip. This may affect the sensory and bio-functional properties of these crops.