Lovro Sinkovič

Impact of Organic Fertilizers on Phenolic Profiles and Fatty Acids Composition: A Case Study for Cichorium intybus L.

Radicchio (Cichorium intybus L.) is an increasingly appreciated leafy vegetable that exhibits great diversity in appearance, including different colored leaves, rosettes, or heads. Varieties of radicchio (‘Treviso’, ‘Verona’ ‘Anivip’, ‘Castelfranco’, and ‘Monivip’) commonly produced in Slovenia were investigated for their phenolic and fatty acid profiles. Plants were grown under organic and/or mineral fertilizer managements in greenhouse conditions. High-performance liquid chromatography analysis was used to study phenolic compounds in radicchio leaf samples. Thirty-three phenolic com‐ pounds were quantitatively evaluated. Significant differences were found between varieties and across different fertilizer managements. The total phenolic amount (TPA) was found in a wide range from 58 to 403 mg/100 g fresh weight (FW). Between varieties, the highest TPA was observed for var. ‘Treviso’ (300 mg/100 g FW) and the lowest TPA was observed for var. ‘Castelfranco’ (125 mg/100 g FW). The main phenolic compounds in radicchio leaves were represented by phenolic acids, chlorogenic acid and cichoric acid, respectively. The fatty acid levels of radicchio leaf samples were determined by the chromatographic analysis of fatty acid methyl esters using gas chromatography with flame ionization detector. The analysis revealed the amounts of C16:0, C18:0, C18:1n9, C18:2n6, C18:3n3, and C20:0 fatty acids. The total fatty acid levels varied from 170 to 500 mg/100 g FW. The highest fatty acid quantity was represented by C18:3n3 (≤63%) followed by C18:2n6 (≤45%) and C16:0 (≤24%). All radicchio samples had a ratio of n-6/n-3 essential fatty acids below 1 and thus in accordance with the current dietary guidelines. Among different fertilizer managements, the highest total fatty acid levels were found for organic fertilizer (384 mg/100 g FW).

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.

Nutrient Evaluation of Different Buckwheat Genetic Resources

Common buckwheat (Fagopyrum esculentum Moench) and tartary buckwheat (Fagopyrum tataricum Gaerth.) are underutilized pseudo-cereals and both considered nutritional food. Eight common and eleven tartary buckwheat accessions acquired from Slovenian plant gene bank were grown at the experimental fields of the Agricultural Institute of Slovenia in 2014. Dried grains were homogenised and analysed for several nutrient parameters: moisture content (11–14% dry weight, DW), total proteins (11–16 % DW), dietary fibre (15–19 % DW), ash (2–6 % DW) and total fats (1.8–2.6 % DW). The fatty acids (C14:0, C16:0, C18:0, C18:1n9, C18:2n6, C18:3n3, C20:0) were determined using gas chromatography, free amino acids (Gly, Glu, Arg, Lys, Asp, Ser, Phe, Ala, Val, Thr, Pro, Ile, Met, His, Cys, Leu, Tyr) by the high-performance liquid chromatography and multi-mineral analysis (K, P, Si, S, Ca, Fe, Cl, Ti, Zn) using X-ray fluorescence spectroscopy. The results show significant differences between two buckwheat species, and their gene bank accessions for investigated nutritional parameters.