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Jerusalem artichoke, a widely consumed edible, is an excellent source of inulin and selected phytochemicals. However, the improvement of its chemical composition by potassium fertilization has not yet been studied. Thus, the aim of the study was to evaluate the effect of different potassium (K) fertilization levels (K 2 O 150 kg ha −1 , 250 kg ha −1 , 350 kg ha −1 ) on the content of inulin; profile and changes in polyphenolic compounds; and the antioxidant capacity, including on-line ABTS antioxidant profiles of freeze-dried tubers originated from Violette de Rennes, Topstar, and Waldspindel cultivars. Inulin content was highest in the early maturing cv. Topstar. The application of 350 kg ha −1 of K fertilizer rates during the growth of cv. Topstar increased the inulin content of tubers by 13.2% relative to the lowest K fertilizer rate of 150 kg ha −1 . In cv. Violette de Rennes, inulin accumulation increased in response to the fertilizer rate of 250 kg ha −1 . A further increase in K fertilizer rates had no effect on inulin content. The inulin content of cv. Waldspindel was not modified by any of the tested K fertilizer rates. Thus, the accumulation of the inulin was cultivar-dependent. In the cultivars analyzed, 11 polyphenolic compounds were identified and polyphenolic compound content was affected by the applied rate of potassium fertilizer, which was dependent on the cultivar. Chlorogenic acid was the predominant phenolic acid in all cultivars, and it accounted for around 66.4% of the identified polyphenolic compounds in cv. Violette de Rennes and for around 77% of polyphenolic compounds in cv. Waldspindel and Topstar.

Three cultivars of Jerusalem artichoke Albik, Rubik and Gute Gelbe were grown under different nitrogen fertilization regimens: 0, 80 and 120 kg N·ha−1. Phenolic compounds were extracted from tubers using 80% (v/v) methanol. The total phenolics were determined with the Folin–Ciocâlteu reagent and antioxidant activity was assessed using the ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)), FRAP (ferric-reducing antioxidant power), and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. The content of individual phenolic compounds was determined by HPLC. The effect of nitrogen fertilization on the total phenolics content was observed for the Albik cultivar. In the Rubik variety the lowest content was recorded at fertilization zero, and in the Gute Gelbe variety at this fertilization level the content of phenols was the highest. At fertilization 120 kg N·ha−1, the highest ABTS test results were noted for all cultivars. For the Albik variety no effect of fertilization on the FRAP test results was noted; for the Rubik variety at zero nitrogen fertilization, the value for FRAP was the lowest, and it was the highest Gute Gelbe. The results of the DPPH test in the Gute Gelbe variety did not depend on the fertilization used. In the other two varieties, the lowest DPPH results were obtained at zero nitrogen regimen. Three main phenolic compounds were determined using HPLC. One of them was chlorogenic acid and the other two were derivatives of caffeic acid. The content of chlorogenic acid in tubers of the Gute Gelbe variety depended on nitrogen fertilization; the highest content of this compound was found in the case of fertilization zero. Statistical analysis showed a correlation between the content of phenolic compounds in tubers and their antioxidant potential. The results of this study suggest great potential for using Jerusalem artichoke tubers as a rich source of phenolic compounds with high antioxidant capacity.

The aim of this study was to compare the thermal, physical, mechanical and chemical properties of white mustard (Sinapis alba L.) seeds of the traditional cultivar 'Radena' and the double low cultivar 'Warta'. The selected thermal properties were determined with an analyser KD2 Pro. Cultivar 'Warta' was characterised by higher thermal conductivity (0. ). Cultivars 'Warta' and 'Radena' had identical thermal diffusivity (0.087 mm 2 s -1 ). The values of the highest initial endothermic peaks and the last endothermic peak were determined from differential scanning calorimetry curves. The mean values of common peaks for both cultivars were determined at −17.5, 86.0 and 402.3 °C for 'Warta', and −16.5, 69.9 and 400

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