Heavy metals in onion (Allium cepa L.) and environmental and health risks.

This study aimed to determine heavy metal content in soil and selected cultivars of onion. Cd content in soil exceeded the limit 2.43 times. Bioavailable forms of Pb and Cd in soil exceeded the critical value 5.9 times and 1.9 times, respectively. Analysed cultivars were not bioaccumulators of monitored heavy metals. However, Pb and Cd content in cultivars Nanas F1, Kappa and Daytona F1 exceeded the maximum limit set by the EU regulation. For Pb this was also the case for the Spirith cultivar. Based on health risk assessment it could be concluded that moderate consumption of onions from the studied localities does not pose a risk to consumers.

Phytochemistry, Bioactivities of Metabolites, and Traditional Uses of Fagopyrum tataricum.

In Tartary buckwheat (Fagopyrum tataricum), the edible parts are mainly grain and sprouts. Tartary buckwheat contains protecting substances, which make it possible for plants to survive on high altitudes and under strong natural ultraviolet radiation. The diversity and high content of phenolic substances are important for Tartary buckwheat to grow and reproduce under unfriendly environmental effects, diseases, and grazing. These substances are mainly flavonoids (rutin, quercetin, quercitrin, vitexin, catechin, epicatechin and epicatechin gallate), phenolic acids, fagopyrins, and emodin. Synthesis of protecting substances depends on genetic layout and on the environmental conditions, mainly UV radiation and temperature. Flavonoids and their glycosides are among Tartary buckwheat plants bioactive metabolites. Flavonoids are compounds of special interest due to their antioxidant properties and potential in preventing tiredness, diabetes mellitus, oxidative stress, and neurodegenerative disorders such as Parkinson's disease. During the processing and production of food items, Tartary buckwheat metabolites are subjected to molecular transformations. The main Tartary buckwheat traditional food products are bread, groats, and sprouts.

Impact of old environmental burden in the Spis region (Slovakia) on soil and home-grown vegetable contamination, and health effects of heavy metals.

Due to several centuries of ongoing mining activities, Middle Spis (Slovakia) is one of the areas with a damaged environment. The contents of Fe, Mn, Zn, Cu, Ni, Pb, Cd, and Hg were determined in the soils and home-grown vegetables (potatoes, carrots, tomatoes). Except for Pb, the contents of heavy metals in the soils of some plots were higher than the limit values. Based on the values of Contamination factor (Cf), Degree of contamination (Cdeg), Geo-accumulation index (Igeo), and Pollution load index (PLI), very high Fe, Cd, and Hg contamination (Cf ≥ 6), very high soil contamination (Cdeg ≥ 20), extremely heavy Fe and Hg contamination (Igeo > 5), resp. moderately pollution to non-pollution (1 < PLI ≤ 2) was found in all plots. In vegetable samples, the maximum levels were exceeded for Cu, Pb, Hg (potato), Pb (carrot, tomato), and Hg (carrot, plot E). Bioaccumulation factor values BAF > 1 were for Cu (carrots, potatoes). Estimated daily intake values for all heavy metals were lower than their tolerable daily intake. Chronic daily intake of heavy metals ranged 2.495E-06 (Hg)-0.1416 (Fe) mg/kg/day. Based on Hazard index values, potato consumption poses a risk (0.8068-1.3057). The results showed that the monitoring of soils and cultivated production is necessary for the investigated area.

Molecular Shield for Protection of Buckwheat Plants from UV-B Radiation.

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn.) and common buckwheat (Fagopyrum esculentum Moench) are adapted to growing in harsh conditions of high altitudes. Ultraviolet radiation at high altitudes strongly impacts plant growth and development. Under the influence of ultraviolet radiation, protecting substances are synthesized in plants. The synthesis of UV-B defense metabolites is genetically conditioned, and their quantity depends on the intensity of the ultraviolet radiation to which the plants and plant parts are exposed. These substances include flavonoids, and especially rutin. Other substances with aromatic rings of six carbon atoms have a similar function, including fagopyrin, the metabolite specific for buckwheat. Defensive substances are formed in the leaves and flowers of common and Tartary buckwheat, up to about the same concentration in both species. In comparison, the concentration of rutin in the grain of Tartary buckwheat is much higher than in common buckwheat. Flavonoids also have other functions in plants so that they can protect them from pests and diseases. After crushing the grains, rutin is exposed to contact with the molecules of rutin-degrading enzymes. In an environment with the necessary humidity, rutin is turned into bitter quercetin under the action of rutin-degrading enzymes. This bitterness has a deterrent effect against pests. Moreover, flavonoids have important functions in human nutrition to prevent several chronic diseases, including obesity, cardiovascular diseases, gallstone formation, and hypertension.

Impact of 3-Year Period as a Factor on the Content of Biologically Valuable Substances in Seeds of White Lupin.

White lupin seed is a unique legume rich in protein and fiber contents, as well as phytochemicals with health potential that contributes to a reduced risk of dyslipidemia, obesity and intestinal dysfunction. This study was focused on the effect of the year on the contents of caffeic acid, 4-hydroxybenzoic acid, trans-ferulic, trans-p-coumaric, quercetin, myricetin, kaempferol, apigenin and genistein, as well as the antioxidant activity and total polyphenols, of seeds of eleven varieties (Lupine albus). The contents of individual phenolic substances were determined by high-performance liquid chromatography-HPLC. The total content of polyphenols and the antioxidant activity were determined spectrophotometrically. The results show that the lowest contents of phenolic acids were found in the seeds from 2018. The caffeic acid and trans-ferulic acid were the most represented among all phenolic acids, during all 3 monitored years (2017, 2018, and 2019). Our results confirm the significant influence of the year of cultivation on the bioactive substances' content in the seeds, and this can be potentially useful for the appropriate selection of locations for lupine growers in Slovakia, taking into account the climatic conditions of the given location. This study provides information about a legume that is underutilized in human nutrition, which may be a valuable source of bioactive substances.

Changes in Antioxidant Properties and Phenolics in Sweet Potatoes (Ipomoea batatas L.) Due to Heat Treatments.

Processing is one of the most crucial factors affecting polyphenol content in foods. Therefore, the study is aimed at the evaluation of heat treatment effects (microwaving, steaming, baking, and boiling) on the content of chlorogenic acids, total polyphenols, and antioxidant activity of three varieties of sweet potato with different flesh colors (Beauregard­orange-fleshed, O'Henry­white-fleshed, 414-purple­purple-fleshed). According to high performance liquid chromatography analysis, chlorogenic acid was the predominant chlorogenic acid in sweet potatoes. Obtained results also suggested the purple-fleshed variety (414-purple) had significantly (p < 0.05) higher total polyphenol content and thus the highest antioxidant activity. Heat treatment positively influenced the chlorogenic acid content, total polyphenols, and antioxidant activity of sweet potatoes. Among the used methods, steaming had the greatest effect on the chlorogenic acids and total polyphenols, while microwaved samples showed the highest antioxidant activity (DPPH). The content of chlorogenic acids and total polyphenols decreased in the order of steaming > baking > microwaving > boiling > raw. However, the individual varieties differed not only in the flesh color but also in the reaction to the used heat treatment methods. Spearman's correlation coefficient showed a strong correlation between chlorogenic acid and antioxidant activity.

Heavy Metals Presence in the Soil and Their Content in Selected Varieties of Chili Peppers in Slovakia.

Capsicum chili peppers are popular vegetables in Slovakia. They provide a supply of health-promoting substances, but contaminated vegetables can pose a serious health risk to the people who consume them. Therefore, the aim of this study was to determine the content of heavy metals (Mn, Zn, Cr, Cu, Ni, Cd, Pb and Hg) in the soil as well as in selected varieties of the genus Capsicum grown in southern Slovakia. The results were compared with the limit values given by the Law no. 220/2004 (valid in the SR) as well as threshold values proposed by the European Commission (EC) (2006). The gained result showed that the total content of Cd (1.64 mg/kg) as well as the available mobile forms of Cd (0.12 mg/kg) and Pb (0.26 mg/kg) was exceeded on the soil on which Capsicum cultivars were grown. The limit values of other monitored heavy metals (Mn, Zn, Cr, Cu, Ni, and Hg) were not exceeded. The studied species of the genus Capsicum did not accumulate monitored heavy metals. It can be stated that consumption of chili peppers does not pose any risk for human health.

Hygienic quality of soil in the Gemer region (Slovakia) and the impact of risk elements contamination on cultivated agricultural products.

The Gemer region (Slovakia) belongs to areas with a high concentration of risk elements. The contents of Cu, Ni, Pb, Cd, Hg and Mn were determined in soils and cultivated agricultural production from lands in three cadastres of the Gemer region (Henckovce (48.713845, 20.426189) and Nizná Slaná (48.717373, 20.4208423), cultivated crop-spring triticale; Gemerská Poloma (48.704523, 20.487645), cultivated crop-maize). Bioavailable forms of Pb (0.306-0.532 mg/kg) and Cd (0.104-0.154 mg/kg), pseudototal forms of Cd (3.07-3.98 mg/kg) and Hg (0.484-2.18 mg/kg) represented the highest risk in soils. The highest contents of Pb (Cd, Hg) were in maize from Gemerská Poloma: 0.898 (0.081, 0.399) mg/kg DM. Soils were classified based on several indicators of soil contamination. The highest values of indicators are: Contamination factor (Cf 29.1-Hg), Degree of contamination (Cdeg 51.5), Potential ecological risk factor (Er 1163-Hg), Potential ecological risk index (RI 1,520), Pollution load index (PLI 4.76), Geo-accumulation index (Igeo 5.60-Hg). All indicators concerned the lands of Henckovce and Gemerská Poloma, RI also concerned the land of Nizná Slaná. Bioaccumulation factor (BAF) was calculated to assess the plant's ability to absorb the risk element. For both crops and all risk elements, BAF values were < 1. Obtained results indicate heavy metal contamination of soils, therefore monitoring of soils in investigated area is necessary.

Concentrations of Phenolic Acids Are Differently Genetically Determined in Leaves, Flowers, and Grain of Common Buckwheat (Fagopyrum esculentum Moench).

Common buckwheat (Fagopyrum esculentum Moench) is a valuable source of proteins, B vitamins, manganese, tryptophan, phytochemicals with an antioxidant effect, and the natural flavonoid rutin. Due to its composition, buckwheat supports the human immune system, regulates blood cholesterol, and is suitable for patients with diabetes or celiac disease. The study aimed to compare the allocation of selected phenolic acids (neochlorogenic acid, chlorogenic acid, trans-caffeic acid, trans-p-coumaric acid, trans-sinapic acid, trans-ferulic acid) and flavonoids (rutin, vitexin, quercetin, kaempferol) in the leaves, flowers, and grain of buckwheat cultivars of different origin. The content of individual phenolics was determined by the HPLC-DAD method. The results confirmed the determining role of cultivar on the relative content of chlorogenic acid, trans-caffeic acid, trans-sinapic acid, vitexin, and kaempferol in buckwheat plants. A significantly negative correlation among concentrations of phenolic acids in different common buckwheat plant parts shows that there are different mechanisms of genetic influences on the concentration of phenolic substances in common buckwheat flowers, leaves, and grain. These differences should be taken into account when breeding buckwheat for a high concentration of selected phenolic substances.

Effects of Adding Legume Flours on the Rheological and Breadmaking Properties of Dough.

The influence of the addition of four legume flours, chickpea, broad bean, common bean and red lentil (in amounts of 5%, 10% and 15% to a wheat-rye composite flour (50:50:0-control flour), in ratios of 50:45:5; 50:40:10; 50:35:15) was studied by analyzing the rheological properties of dough in order to further exploit the functionality of legume flours in bakery products. The rheological properties of dough were monitored using a Mixolab 2. A Rheofermentometer F4 was used to check the dough fermentation, and a Volscan was used for evaluating the baking trials. The addition of different legume flours in the mixtures resulted in different viscoelastic properties of the dough. The results showed a weakening of the protein network depending on the amount of legume flour added and on the specific legume flour. On the contrary, all samples with a higher proportion of legume flour showed an increased resistance to starch retrogradation. All flours had the ability to produce a sufficient volume of fermenting gases, with the exception of flours with a higher addition of broad bean flour, and the baking test confirmed a lower bread volume for bread with this addition. The results of the sensory evaluation indicated that legume flour additions resulted in breads with an acceptable sensory quality, in the case of additions of 5% at the same level as the bread controls, or even better. The aromas and flavors of the added non-cereal ingredients improved the sensory profile of wheat-rye bread. Breads with additions of chickpea, common bean and broad bean had a considerable proportion of darker colors in comparison to the control bread and bread with red lentil.

Comparison of Heavy Metal Intake by Different Species of the Genus Allium L.

Allium vegetables belong to the most widespread and commonly grown vegetables in Slovakia. In this study, we dealt with the content of selected heavy metals (Zn, Mn, Cr, Cu, Ni, Pb, and Cd) in cultivated garlic (Záhorský, Lukan, Makoi), onion (Amika, Red Matte, Diamant), and leek (Bavaria, Golem, Tango). We determined the total content of heavy metals (aqua regia), and available-mobile forms of heavy metals (1 M NH4NO3) in soils. Analytical final procedure was flame AAS. The results were compared with the limit values given by the Law no. 220/2004 (valid in the SR) as well as threshold values proposed by the European Commission (EC) (2006). Gained result showed that the total content of Cd (1.26 mg.kg-1) as well as the available mobile forms of Cd (0.16 mg.kg-1) and Pb (0.64 mg.kg-1) was exceeded on the soil on which Allium species were grown. Determined contents of heavy metals in garlic were in the range of 0.03-0.07 mg Cd.kg-1 FM (fresh matter), 0.02-0.11 mg Pb.kg-1 FM (fresh matter), in onion ranged from ND (not detected) to 0.03 mg Cd.kg-1 FM (fresh matter), 0.09-0.2 mg Pb.kg-1 FM (fresh matter), and in leek were in the range of, 0.07-0.13 mg Cd.kg-1 FM (fresh matter), and 0.3-0.5 mg Pb.kg-1 FM (fresh matter). Based on the obtained BAF values, we can conclude that the genus Allium does not belong to the accumulator of evaluated hazardous metals. Safe food production requires constant monitoring of hazardous metals in raw materials of plant origin, as these metals can have serious negative effects on human health.

Accumulation of Selected Metal Elements in Fruiting Bodies of Oyster Mushroom.

The species Pleurotus ostreatus is a commercially, gastronomically, and biotechnologically important fungus. Its strain variability has been little researched. The study provides an evaluation of 59 oyster mushroom production strains in terms of the ability to accumulate selected metals in the cap and stipe. The fruiting bodies were grown under identical model conditions on straw substrate. Metal concentrations (ET-AAS) in dry fruiting bodies ranged in values 1.7-22.4 mg kg-1 for Al, 2.6-9.7 mg kg-1 Ba, 199-4560 mg kg-1 Ca, 1.7-12.0 mg kg-1 Cu, 12-120 mg kg-1 Fe, 16,000-49,500 mg kg-1 K, 876-2400 mg kg-1 Mg, 0.39-11.0 mg kg-1 Mn, 46-920 mg kg-1 Na and 11-920 mg kg-1 for Zn. More Cu, Fe, K, Mg, Mn, Zn accumulated in the cap, while in the stipe Ba was amassed. No significant difference was found between Al, Ca and Na between the accumulation in the cap and the stipe. Furthermore, the dependence of metal uptake from the substrate depending on the fortification of the substrate was confirmed. Statistically significant (p < 0.05) synergistic relationships were shown in pairs Al and Ba, Al and Fe, Ba and Na, Ba and Ca, Ca and Na, Cu and Fe, Fe and Mn, Fe and Zn, K and Mg, K and Mn, K and Zn, Mg and Mn, Mg and Na, Mg and Zn and Mn and Zn in the substrate without the addition of sodium selenate to the substrate. Altered relationships were observed after the application of sodium selenate to the substrate, synergism of Se and Ni, Se and Co and Se and Hg, Cu and Mn, Cu and Fe, Zn and Co, Zn and Ni, Zn and Hg, Mn and Fe, Mn and Cr, Co and Ni, Co and Hg, Ni and Hg, Pb and Cd. The findings of the study may help in the selection of production strains with hypercumulative properties for a particular metal and subsequent use in the addition of fortified fruiting bodies (e.g., with Zn). Based on the study the strains less sensitive to the accumulation of hazardous metals is possible to select for large-scale production, which is important from the perspective of food safety.

The temperature threshold for the transformation of rutin to quercetin in Tartary buckwheat dough.

The aim was to determine conditions under which rutin can be retained during production of Tartary buckwheat (Fagopyrum tataricum) dough. Tartary buckwheat flour was hydrothermally treated by mixing with water at 25, 40, 60, 80 and 95 °C, with unprocessed Tartary buckwheat flour as control. With hydrothermal treatments at 25, 40 and 60 °C, most of the rutin was transformed to quercetin. However, for hydrothermal treatments at 80 and 95 °C, rutin was retained due to denaturation of the rutin-degrading enzymes during hydrothermal treatment. This is the first report to describe a temperature threshold for denaturation of rutin-degrading enzymes in any buckwheat material. Tartary buckwheat dough produced at 95 °C contained 12 mg rutin/g dry matter. Based on these characteristics, dough from hydrothermally treated Tartary buckwheat is a promising, rutin-rich functional food material.

Accumulation and environmental risk assessment of heavy metals in soil and plants of four different ecosystems in a former polymetallic ores mining and smelting area (Slovakia).

Heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in soils and plants of four different ecosystems (forest, grassland, agro and urban ecosystem) at different distances from the source of the pollution were analyzed in order to assess and compare soil contamination in the various ecosystems and determine the potential accumulation of plants depending on the place they inhabit. Correlation relationships among heavy metals in soils differ depending on the ecosystem, and between soil and plant, the heavy metals showed significant correlation for Cu, Mn, Ni, Pb and Zn. Contamination factor (Cf), degree of contamination (Cd) and pollution load index (PLI) were used in order to determine the level of environmental contamination of the study area. All studied ecosystems were rated as moderately contaminated (except agroecosystem, which was found as low contamination ecosystem) according to Cd and extremely polluted according to PLI. The highest pollution in both cases was found in urban ecosystem, and Cd, Cu and Fe were determined as the biggest pollutants.

Adsorption Processes of Lead Ions on the Mixture Surface of Bentonite and Bottom Sediments.

The adsorption of contaminants plays an important role in the process of their elimination from a polluted environment. This work describes the issue of loading environment with lead Pb(II) and the resulting negative impact it has on plants and living organisms. It also focuses on bentonite as a natural adsorbent and on the adsorption process of Pb(II) ions on the mixture of bentonite and bottom sediment from the water reservoir in Kolínany (SR). The equilibrium and kinetic experimental data were evaluated using Langmuir isotherm kinetic pseudo-first and pseudo-second-order rate equations the intraparticle and surface diffusion models. Langmuir isotherm model was successfully used to characterize the lead ions adsorption equilibrium on the mixture of bentonite and bottom sediment. The pseudo second-order model, the intraparticle and surface (film) diffusion models could be simultaneously fitted the experimental kinetic data.

Environmental Contamination by Heavy Metals in Region with Previous Mining Activity.

Due to its status as one of the most contaminated regions in Slovakia, 45 soil and plant samples were collected in the Middle Spis region. In soil, the exchangeable soil reaction, humus content and heavy metals content (Zn, Cd, Cu, Pb, Hg) were determined. Total content of heavy metals (TC-HMs) and content of mobile forms (MF-HMs) in soil, as well as metal content in plants, were determined by atomic absorption spectrometry. The concentration ranges for total Zn, Cd, Cu, Pb and Hg in soil were 33.1-953, 0.65-6.73, 11.0-913, 26.5-165 and 0.28--415 mg/kg, respectively. The overall concentration ranges of these metals in plants of two types (Athyrium filix-femina L. and Poaceae herbs) were 12.4-158.6, 0.10-1.63, 3.34-85.7, 0.09-29.7 and 0.01-12.8 mg/kg, respectively. Despite the values of Zn, Cd, Cu, Pb and Hg content in the soil exceeding limit values, only the Hg content in plants presented an ecological risk.

Changes of Polyphenolic Substances in the Anatomical Parts of Buckwheat (Fagopyrum esculentum Moench.) during Its Growth Phases.

In this study the changes of total polyphenolics in different anatomical parts (stems, leaves, flowers and seeds) of common buckwheat (Fagopyrum esculentum Moench.) during vegetation period were analysed. The content of total polyphenolics was evaluated in growth phase I (formation of buds), phase II (at the beginning of flowering), phase III (full blossoming) and phase IV (full ripeness). In all growth phases (GP) the stems and leaves were evaluated and statistically significant differences in polyphenolics content between the two parts were confirmed. Statistically significant differences (p < 0.01) in polyphenolics content (in GP II and III) between stems and leaves; and between stems and flowers were found. In flowers an average of 13.8 times higher and in leaves 6 times higher concentration of polyphenolics in comparison with stems was measured. In GP III the content of polyphenolics in common buckwheat was following: flowers > leaves > achene > stems. In flowers an average of 11.9 times higher, in leaves 8.3 times higher and in achenes 5.9 times higher contents of polyphenolics compared with stems were found. In GP III and IV (leaves, achenes, stems) the leaves contained in average 20 times higher and achenes 5.6 times higher polyphenolics than stems.

Degradation of rutin and polyphenols during the preparation of tartary buckwheat bread.

The impact of bread making and baking procedure on rutin, quercetin and polyphenol concentration and antioxidant activity of tartary buckwheat (Fagopyrum tataricum) bread and breads made of mixtures of tartary buckwheat and wheat flour was studied. A decrease in polyphenol concentration through baking was observed in all samples. The high DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging capacity in mixed breads (32-56%) and in tartary buckwheat bread (85-90%) decreased slightly through the bread making process, while an increase of antioxidant activity in bread made of 100% wheat flour during bread making was observed. With the addition of water to mixtures containing tartary buckwheat during the preparation of the dough, rutin concentration decreased, while quercetin concentration increased. The rutin concentration continued to decrease during the bread baking process, while the concentration of quercetin remained stable. After baking, rutin (0.47 mg/g) was present only in bread made of 100% tartary buckwheat flour along with quercetin (4.83 mg/g).