Parameters for discrimination between organic and conventional production: A case study for chicory plants (Cichorium intybus L.).

Organic crop production has become a highly attractive way of production over the world and thus the need for robust analytical techniques for their authentication. The main aim of this study is to identify appropriate biomarkers to discriminate between organic and conventionally grown chicory. Chicory is an appreciated leafy vegetable among producers and consumers, especially due to its undemanding cultivation and content of bioactive substances. Six different fertility management practices (control, two organic, two mineral, and a combination of organic and mineral fertilizers) were used to produce five chicory cultivars in a glasshouse pot experiment. Analysis of bioactive compounds, nitrogen assimilation, multi-elemental profiling and stable isotope ratio determination of carbon (C), nitrogen (N) and sulphur (S) were performed to differentiate between organic and conventional production. In this study, nitrogen isotopes are found to be an excellent way of identifying organically produced chicory of a different variety with the highest δ15N values. Conversely, the same samples had the lowest δ34S values indicating that also stable isotopes of S could be used as a marker for the authentication of organic production.

Nitrate and nitrite contamination of vegetables in the Slovenian market.

Overview of the quality of domestic and imported vegetables in Slovene market was investigated in terms of nitrate and nitrite contamination. In total, 145 samples (rocket, lamb's lettuce, silverbeet, spinach, lettuce, cabbage, radicchio, string beans, carrots, cucumber, potato, cauliflower, pepper and tomato) were bought in supermarkets and market places in Ljubljana in 2017. Values over 1000 mg NO3- kg-1 were found in 30% of randomly selected samples. The highest nitrates (4000-7600 mg kg-1) were determined in rocket, lamb's lettuce, silverbeet, and spinach. They were bought in supermarkets declared as imported samples. Regarding EU regulatory limits, available for rocket, lettuce, and spinach, 17% of the samples exceeded the threshold values. Furthermore, some of them were designated as ecological product (ECO). There are no maximum limits for lamb's lettuce; however, all samples from supermarkets, declared as imported samples, contained very high values of nitrates (>3500 mg NO3- kg-1).

Phenolic profiles in leaves of chicory cultivars (Cichorium intybus L.) as influenced by organic and mineral fertilizers.

Chicory (Cichorium intybus L.) is a typical Mediterranean vegetable, and it shows great morphological diversity, including different leaf colours. Five cultivars commonly produced in Slovenia ('Treviso', 'Verona', 'Anivip', 'Castelfranco', 'Monivip') were grown in pots under controlled conditions in a glasshouse, with organic and/or mineral fertilizers administered to meet nitrogen requirements. HPLC analysis was carried out to study the phenolic compositions of the leaves. A total of 33 phenolic compounds were extracted from these chicory leaves and were quantitatively evaluated in an HPLC-DAD-based metabolomics study. Among the cultivars, the highest TPC was seen for 'Treviso' (300.1 mg/100 g FW), and the lowest, for 'Castelfranco' (124.9 mg/100g FW). Across the different treatments, the highest TPC was in the control samples (254.3 mg/100 g FW), and the lowest for the organic (128.6 mg/100 g FW) and mineral fertilizer (125.5 mg/100 g FW) treatments. The predominant phenolic compounds in all of the samples were hydroxycinnamic acids, including chlorogenic and cichoric acid. Fertilizer administration provides a discriminant classification of the chicory cultivars according to their phenolic compounds.

Carotenoid and chlorophyll composition of commonly consumed leafy vegetables in Mediterranean countries.

Major chloroplast pigments in five leafy vegetables (chicory-Cichorium intybus, cv. 'Anivip' and cv. 'Monivip', dandelion-Taraxacum officinale, garden rocket-Eruca sativa and wild rocket-Diplotaxis tenuifolia), commonly consumed in Mediterranean countries, have been separated by high-performance liquid chromatography (HPLC) on a reversed-phase column. Three classes of pigments were identified and quantified: xanthophylls (oxygenated carotenoids), carotenes (hydrocarbon carotenoids) and chlorophylls. The contents of the pigments in the analysed leafy vegetables varied significantly. The results indicated that selected leafy vegetables were moderately rich in xanthophylls, primarily lutein (3.87-7.44mg/100g fwt). Other xanthophylls were detected in relatively small quantities. The provitamin A carotenoids (α- and ß-carotene) were also detected, but α-carotene were not present in chicory cultivars and in dandelion. The ratio of chlorophyll a/b varied from 2.44 to 2.67 depending on the species. The highest content of all the analysed constituents was found in the garden rocket.