Bioactive compounds and macroelements of chicory plants (Cichorium intybus L.) after hydroponic forcing in different nutrient solutions

The aim of this study was to measure the bioactive compounds and elemental composition in the leaves of different chicory (Cichoruim intybus L.) cultivars after hydroponic forcing. Five chicory cultivars were studied: three red coloured cultivars: ‘Treviso’, ‘Verona’, and ‘Anivip’; one red-spotted cultivar ‘Castelfranco’; and one green cultivar ‘Monivip’. Developing chicory roots were forced in three different nutrient solutions enriched in nitrogen (+N), enriched in potassium (+N/K), or enriched in phosphorus (+N/P/K) to obtain new vegetative apical buds called chicons, or ‘Belgian endive’. Each of the nutrient solutions was used at three concentrations: 1%, 2%, and 3%. Fifty leaf samples (5 cultivars × 10 nutrient solutions) were used for analyses. Total phenolic content, antioxidant potential, and total flavonoid content were determined using spectrophotometric methods at the appropriate wavelengths, and multi-elemental analysis (P, S, Cl, K, Ca, Fe, Zn, Mn, Rb, Br, and Sr) was conducted using energy dispersive X-ray fluorescence spectroscopy. The highest total phenolic and total flavonoid contents of the chicons were observed with the nutrient solution enriched in K, followed by the solution enriched in N, and P. The highest antioxidant potential was observed with the nutrient solution enriched in N. Multi-element analysis detected the major macroelements (> 1 g·kg-1 dry weight) as K, P, Ca, Cl, and S. The nutrient solutions enriched in K and P generally showed the highest contents of these two macroelements in the chicons. Linear discriminant analysis for 19 parameters derived from 43 samples of five cultivars of chicons showed good discrimination between cultivars and nutrient solutions used for hydroponic forcing.