► Pigments of chicory, dandelion, garden rocket, and wild rocket were examined. ► Xanthophylls, carotenes and chlorophylls were identified and quantified. ► Tested species were moderately rich in ...xanthophylls, primarily lutein. ► α-carotene was detected in garden and wild rocket, and β-carotene in all species. ► The highest content of all analysed constituents was found in garden rocket.
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 β-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.
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•Phenolic profiles of chicory are highly influenced by cultivar and fertilizer use.•33 Phenolics were extracted and further identified from the five chicory cultivars.•Hydroxycinnamic acids ...(chlorogenic, cichoric) are predominant phenolics.
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’ (300.1mg/100g FW), and the lowest, for ‘Castelfranco’ (124.9mg/100g FW). Across the different treatments, the highest TPC was in the control samples (254.3mg/100g FW), and the lowest for the organic (128.6mg/100g FW) and mineral fertilizer (125.5mg/100g 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.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The objective of this study was to evaluate the impact of cultivar and covering with nonwoven agrotextile on vegetative growth parameters and the productivity value of sweet potato (Ipomoea batatas ...L.). A field experiment was conducted during the 2018 growing season, at the experimental field of the Biotechnical Faculty in Ljubljana (46° 04′ N latitude; 14° 31′ E longitude, 305 m above sea level). The soil was gravel clay with a pH of 6.7, and a soil depth of 40–60 cm. The research involved the following Slovenian cultivars of sweet potatoes: Lučka, Janja, and Martina. Distance between rows was 1.2 m, while in-row distance was 1.4 m. The experiment was conducted in a randomized complete block design with plots arranged factorially and replicated four times. The seedlings were planted on 20 May. A half of the plots were covered with polypropylene nonwoven textile (17 g/m2). The uncovered half of the plots served as control plots. The recommended cultural practices were performed as needed during the experiment. The temperature under the covers was on average 5.5 °C higher than in the unprotected area. The crops were harvested 132 days after planting. Covering significantly and positively affected vegetative growth – that is the height of the vines, leaf number, leaf area index, and haulm dry weight. In contrast, the nonwoven polypropylene cover had no significant effect on the number of branches per crop. The use of agrotextile significantly increased tuber length and diameter, tuber number, tuber weight, and total yield in comparison with traditional cultivation with no plant cover. Statistical analysis showed that cv. Janja had the significantly higher yield (7.49 t/ha) compared to cv. Lučka (6.68 t/ha) and cv. Martina (6.16 t/ha).
Nitrate (NO3–) and nitrite (NO2–) levels of a total 1195 samples of nine different vegetables (lettuce, potato, cabbage, carrot, string beans, tomato, cucumber, cauliflower and pepper) collected at ...several locations of an intensive agricultural area in Slovenia were analysed during a period of 13 years. The content of NO2– and NO3– ions in commercial mature samples was determined using a segmented flow analyser. The average NO3– content was the highest in lettuce (962 mg/kg), cabbage (795 mg/kg), string beans (298 mg/kg), carrot (264 mg/kg), cauliflower (231 mg/kg), potato (169 mg/kg) and was moderately high in cucumber (93 mg/kg) and pepper (69 mg/kg). A low NO3– content was found in tomato (2– did not exceed 0.5 mg/kg, with the exception of potato (1.08 mg/kg). Six samples of lettuce exceeded the maximum permissible level of NO3– according to current European Union (EU) legislation. Based on the results of our investigation, we assessed the approximate daily intake (DI) of NO3– and NO2– to human body. The results indicated that with the consumption of potato, the daily intake per inhabitant is close to the acceptable DI permitted in EU.
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.
•Five chicory cultivars were grown in a pot experiment.•Six different fertility management practices were applied.•Differences in bioactive compounds content and nitrogen assimilation were evaluated.•Multi-elemental profiling and stable isotope ratios of light elements were studied.•Parameters to discriminate organic and conventionally grown chicory were identified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The use of nitrogen fertilizers is one of the main effects for the accumulation of nitrates in plants. Conventional agriculture, in comparison to integrated and organic farming, causes greater ...environmental pollution and poorer quality of crops. Within the framework of the research, we studied the influence of the method of cultivation on the content of nitrates in the samples of lettuce (Lactuca sativa L.). The samples were received directly from growing areas from different parts of Slovenia and analysed in the laboratory for the nitrate content (NO3-) according to the accredited method. The samples from conventional cultivation showed the highest sample representation (51 %), with values in the highest concentration range (1000 - 2500 mg of NO3- kg-1, one sample exceeded 2500 mg kg-1 fresh mass). Within the framework of integrated cultivation, there were less such samples (34 %), and among the samples from organic cultivation no sample exceeded 1000 mg of NO3- kg-1. Of 88 analysed samples, one sample exceeded the statutory limit value applicable to lettuce of the type Iceberg ('Ljubljanska ledenka'). On average, the Iceberg samples contained more nitrates than other types of lettuce.
The genetic composition of sweet potato Ipomoea batatas (L.) Lam. (2n = 6x = 90) is reflected in different levels of genetic variation. The main objective of the present study was a comparison of ...genetic diversity parameters of different ploidy levels (2n, 4n, and 6n codominant allele determination), analyzed on two high-resolution capillary platforms. Fragment analysis was performed by applying SSR markers on a 3130XL Genetic Analyzer (ABI 3130) and QIAxcel Advanced System (QX). A high level of expected heterozygosity (He) as a measure of genetic diversity was observed for both ABI3130 (0.731) and QX (0.679). Molecular variance was 17% for ABI3130 and 10% for QX. Comparison between genetic distance matrices based on allele lengths showed a moderate Mantel correlation coefficient (rxy = 0.557) between ABI3130 and QX. Global cluster analysis using the Bayesian approach distributed the observed genotypes into two clusters on both capillary platforms. Our results show that the two high-resolution capillary electrophoreses for codominant data on 2n, 4n, and 6n levels are applicable in genetic diversity studies but their efficiency depends on in-resolution expectations, financial resources, available time, and the equipment of the laboratory.
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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 NO
3
ˉ
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 NO
3
ˉ
kg
−1
).
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The standard method of EN 12014-7 was used for the determination of nitrate content in vegetables in the Central Laboratory of the Agricultural Institute of Slovenia. Trueness of the method was ...verified by the analysis of samples in the interlaboratory proficiency testing scheme Bipea (Bureau Interprofessionnel d'Etudes Analytiques). Linearity was confirmed by multiple linear regression; the correlation coefficient (R2) was 0.9993. The limit of detection (LOD) was calculated as 0.8 mg NO3-/kg and limit of quantification (LOQ) 3.0 mg NO3-/kg. Relative standard deviation (RSD) of repeatability was 4.6% and RSD of reproducibility 8.9%. The relative uncertainty of repeatability and reproducibility were 10.5% and 20.2%, respectively. The method has been accredited by the French Accreditation Committee COFRAC in 2007 and by the national Slovene Accreditation in 2012.
The phenolic profiles of leaves of hydroponically forced chicons from five chicory (Cichorium intybus L.) cultivars were determined: ‘Treviso’, ‘Verona’, ‘Anivip’, ‘Castelfranco’ and ‘Monivip’. The ...chicory roots were forced in the dark in three fertiliser solutions enriched in nitrogen (N), phosphorus (P) and/or potassium (K) (i.e., N/P/K, N/P, N alone), each applied at 10, 20 and 30 g/L. Phenolics were extracted from the chicon leaves and quantitatively evaluated in an HPLC-DAD–based study. ‘Castelfranco’ showed the highest total phenolics (19.79 mg/g dry weight DW), and ‘Monivip’ the lowest (15.31 mg/g DW). Across the nutrient solutions, the highest total phenolics was with N/K-1% (19.87 mg/g DW), followed by N/P/K-1% (18.91 mg/g DW), and the lowest with N-1% (14.22 mg/g DW). Determining these phenolics profiles of forced chicons not only contributes to the knowledge of their nutritional value, but also provides a solid foundation for further understanding of their total phenolics formation during hydroponic forcing.
•Under different nutrients, 44 phenolics were extracted from five chicons cultivars.•The phenolics varied widely among analysed hydroponically forced chicons.•Twelve phenolics were specifically identified using HPLC-DAD metabolomics.•Chicons phenolics profiles are influenced by cultivar and forcing nutrient solution.•The remaining grouped unknown phenolic compounds are the predominant phenolics.
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