Home > Search Results: "Biologicky aktivní fenolické látky v zemědělských plodinách"
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National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Quantitative and qualitative changes of phenolic compounds in alder leaf litter
 Elhottová, Dana ; Vrchotová, Naděžda ; Tříska, Jan ; Krištůfek, Václav
Quantitative as well as qualitative changes of phenolic compounds were investigated in different decomposition stages (I-IV) of native alder leaf litter. The Folin-Ciocalteau method was applied for the determination of total phenolic compounds and the reserved phase HPLC for the determination of the phenolic acids. Both values decreased in dependence on stage of litter decomposition. The reduction of the total phenolic compounds and the phenolic acids was 20% and 50%, respectively, in the most decomposed litter (stage IV) in comparison with fresh litter (stage I, 100%). The ratio of free (simple extracted) and bound phenolic compounds (extracted after acid hydrolysis) in the group of total phenolic compounds and phenolic acids was determined. The characteristic feature of the fresh litter (stage I) was higher amount of the free phenolic acids as well as higher ratio of the free phenolic compounds to the bound ones. The following stage II was characterised by two times higher portion of free to bound total phenolic compounds in contrary to phenolic acids where the bound acids dominat ed over the free ones. Higher level of bound to free compounds in both observed phenolic groups was typical for the most decomposed litter samples (stage III and IV).In addition, the stage III and IV were characterised by new compounds, which were formed in the litter during its decomposition and were not detectable in the previous stages (I,II).
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The effects of cultivation conditions on polyphenol compounds levels in potato tubers periderm in varieties differing in their susceptibility to common scab
 Krištůfek, Václav ; Diviš, J. ; Dostálková, I.
Field and glasshouse trials were performed in 2000 and 2001 to estimate total polyphenol contents in 15 potato cultivars from two sites that differed in the level of scab incidence. Polyphenol content was determined spectrophotometrically by Folin-Ciocalteau reagent at a wavelength 765 nm in tuber peelings of cultivars less and more susceptible to common scab. The polyphenol content of tuber peeling was influenced by cultivar, site, year and age of tuber periderm and was not influenced by maturity. The highest polyphenol content was observed in potato cultivars less susceptible to the scab. Regression analysis showed that negative relation occurs between polyphenol content and potato scab incidence (P=0,006). The polyphenol content significantly decreased during vegetative period.
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