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This study contains data of seven blue cultivars of table grape (Vitis vinifera L. and Vitis labrusca L.): Attika, Early Cardinal, Eszter, Chasselas rosé, Königliche Esther, Muscat bleu, and Nero. The following were determined in intact berries: malic, tartaric, and titratable acids, pH values, sugar content, and antioxidant capacity. Concentrations of the following compounds were determined in the pulp of analysed berries: phenolic acids and catechins. The last analysis focused on skins; in addition to the same phenolic acids and catechins, excluding epicatechin, analysed from pulp; ferulic acid and stilbenes were also studied. Higher contents of procyanidin B2 and gallic acid were found in the pulp as compared to those found in skins. Studies during the ripening stage showed that the higher ratio of procyanidin B2 and gallic acid concentrations in the pulp vs. skins relates to late-ripening cultivars, while for early-ripening cultivars a lower ratio was observed. Contents of phenolic acids, catechin, stilbenes, and anthocyanins were studied by means of LC-DAD; other compounds were measured by FTIR.

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The influence of the injection of nitrogen fertilizers with the CULTAN system (Controlled Uptake Long Term Ammonium Nutrition) on nitrogen uptake by winter wheat (Triticum aestivum L.) was observed at small-plot field experiments under conditions of the Czech Republic (central Europe) during 2007–2013. The CULTAN system consisting in the injection of all the nitrogen in one dose was compared with conventional broadcast surface fertilization which is carried out in three partial nitrogen doses. The total nitrogen dosage was 150 kg N.ha−1. If the CULTAN fertilization was carried out at the beginning of tillering of winter wheat (BBCH 22) instead of at the end of tillering (BBCH 29), the CULTAN-treated winter wheat did not suffer from nitrogen deficiency at the BBCH 45 (boot stage) and BBCH 51 (beginning of heading) growth stages. Nitrogen utilization efficiency and biomass production efficiency were significantly higher with the CULTAN treatment compared to the conventional fertilization whereas nitrogen uptake efficiency tended toward lower values with the CULTAN treatment. Nitrogen use efficiency (NUE), post-heading nitrogen uptake, the contribution of nitrogen translocation to the total nitrogen in grain, the partial factor productivity of nitrogen as well as grain yield were not significantly influenced by the CULTAN system. Prolonged nitrogen uptake from the soil with the CULTAN treatment resulting in delayed plant senescence was not confirmed. Neither an application of sulphur-containing fertilizer nor the increased dosage of nitrogen (200 kg N.ha−1) positively affected the studied parameters.

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The aim of this study was to observe the influence of the amount of precipitation during the grain filling period on nitrogen uptake and grain yield of spring barley fertilized by ammonium injection. Conventional nitrogen fertilization before sowing and CULTAN (Controlled Uptake Long Term Ammonium Nutrition) injection fertilization were compared during a 5-year small-plot field experiment under the conditions of Central Europe. In contrast to conventional nitrogen fertilization, with the CULTAN treatment there was observed no significantly negative effect of below-average precipitation during the grain filling period on post-heading (BBCH 51) nitrogen uptake from the soil with applications of 80 and 130 kg N.ha−1, grain yield, nitrogen uptake efficiency (NUpE) and thousand-grain weight with an application of 80 kg N.ha−1, nor there was a significantly positive effect on the contribution of nitrogen translocation to total nitrogen in the grain with an application of 130 kg N.ha−1. CULTANtreated plants achieved a significantly higher harvest index than conventionally treated plants with an application of 80 kg N.ha−1. Below average precipitation during the grain filling period had a significantly negative effect on nitrogen use efficiency (NUE) with both treatments. Using the CULTAN treatment leads to significantly lower flag leaf area compared to conventional treatment with an application of 80 kg N.ha−1. The application of 130 kg N.ha−1 brings no benefits to spring barley production.

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Acta Alimentaria
Authors: E. Tománková, J. Balík, I. Soural, P. Bednář, and B. Papoušková

This study presents findings from comparing the properties of anthocyanin pigments: i. malvidin-3-glucoside (Mal-3-G), the most significant anthocyanin present in young red wine; ii. Vitisin A (5-carboxypyranomalvidin-3-glucoside), a major product from a reaction induced in red wine between Mal-3-G and pyruvic acid during its ageing. These pigments were determined and compared to the absorption spectrum in 200–770 nm at various pH values, such results including the ability of cation Al3+ to change the values of absorbance. Changes in the colour parameters L* a* b* were determined in the CIELAB colour space of Mal-3-G and Vitisin A in relation to pH and the addition of AlCl3. Both coloured compounds were investigated for their resistance to discoloration by sulphur dioxide. Total antioxidant activity was evaluated by two methods (FRAP, DPPH), and the values were compared to other phenols.

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A number of methods have been applied to measure total antioxidant capacity (TAC), including FRAP, which is based on reducing the amount of iron ions in a complex compound. Researchers often use measurement of absorbance 10 min after mixing a sample with the FRAP reaction solution to calculate TAC. The FRAP solution has been shown to alter absorbance over time by ca 0.0010–0.0020 per hour, under storage conditions. This article intends to show that some substances do not fully or sufficiently react within the common analysis period. It is evident from the results that some substances react more quickly and others very slowly. Absorbance in relation to various phenols was measured. Compared to the levels of absorbance at 10 min, mean absorbance at 48 h was higher by 5,395% for vanillin, 426% for caffeic acid, 170% for sinapinic acid, 67% for gallic acid, 19% for syringic acid, and only by 4% for Trolox. Results for vanillin and caffeic acid indicate potential auto-catalysis.

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