The aim of this study was to evaluate the contamination of six edible wild species of mushrooms (Boletus pulverulentus, Cantharellus cibarius, Lactarius quietus, Macrolepiota procera, Russula xerampelina and Suillus grevillei) by heavy metals (Hg, Cd, Pb, Zn, Cu, Ni, Cr, Co, Mn and Fe). Mushroom samples were collected from sites contaminated by emissions from mining and processing of polymetallic ores in operation during the period 1969-1993 in Rudňany, southeast Slovakia. The four study sites spanned up to a 5-km distance from the emission source. The collected mushroom samples were analyzed using Flame Atomic Absorption Spectrophotometry and/or Flame Atomic Absorption Spectrophotometry with graphite furnace. Mercury, Cd and, in some samples, also Pb present the highest risks in terms of contamination of the food chain following subsequent consumption. The content of two metals in the dry matter (dm) of the mushrooms exceeded the limits set by the European Union (EU; Cd: 0.5 mg/kg dm, Pb: 1.0 mg/kg dm). The highest mean contents of the eight metals recorded for S. grevillei were 52.2, 2.15, 107, 104, 2.27, 2.49, 81.6 and 434 mg/kg dm for Hg, Pb, Zn, Cu, Ni, Cr, Mn and Fe, respectively. The highest content of Cd was recorded in M. procera (3.05 mg/kg dm) and that of Co in L. quietus (0.90 mg/kg dm). The calculated weekly intake for Hg, Pb and Cd shows that regular consumption of mushrooms from the studied area poses risks to human health.

Onion (Allium cepa L.) is one of the most important vegetable crops widely consumed in the world. The bulb onion is grown as fresh shoots and as bulbs for consuming uncooked, cooked, and pickled or production of seed and sets. They can be eaten raw, boiled, steamed and roasted. Onion has high nutritional value. Onions are a good source of vitamins, minerals and major component like polyphenols, flavonoids, fructooligosaccharides, thiosulfinates and other sulfur compounds. Polyphenols belong to significant antioxidants in human diet. Antioxidant compounds (polyphenols, flavonoids) scavenge free radicals, inhibit the oxidative mechanisms that lead to degenerative diseases. Antioxidant compounds in food play an important role as a health protecting factor. Onions have a wide range of beneficial properties for human health, such as anti-cholesterolaemic, anti-mutagenic and antioxidant capacity. In this work we evaluated content of total polyphenols and antioxidant activity in selected varieties of onion. Samples of plant material we collected at the stage of full maturity in the locality of Pružina. Pružina is locality without negative influences and emission sources. Total polyphenols content and antioxidant activity were measured in six varieties of onion, namely in red variety (Red matté), in yellow varieties (Boston, Bingo, Sherpa) and white varieties of onion (Diamond, White dry). The content of the total polyphenols was determined by using the Folin-Ciocalteu reagent (FCR). Antioxidant activity was measured by using a compound DPPH˙. In the present experiment it was detected, that total polyphenols content in samples ranges from 142.01 mg.kg -1 GAE (white variety of onion-White dry) to 1083.04 mg.kg -1 GAE (red variety of onion-Red matté). Statistically significant highest value of total polyphenols (1083.04 mg.kg -1 GAE) was recorded in variety Red matté. Another indicator that has been evaluated and compared was the antioxidant activity. The values of antioxidant activity were in interval from 7.74% to 41.67%. Based on the measured values of antioxidant activity in onion the samples can beclassified as follows: Red matté (41.67%) > Boston (25.77%) > Sherpa (24.34%) > Bingo (19.54%) > White dry (8.10%) > Diamond (7.74%).

Keywords: Onion (Allium cepa L.), total polyphenols, antioxidant activity, potassium INTRODUCTIONAmong all vegetables, onion is a species consumed widely across the world. Onion (Allium cepa L.) is one of the most important vegetable crops with a world production of about 55 million tonnes. Its consumption is attributed to several factors, mainly heavy promotion that links flavour and health and the popularity of onion-rich ethnic foods Dini et al., (2008). Onion (Allium cepa L.) is medical herb and belongs to the family Alliaceae. Onion (Allium cepa L.) is a rich source of flavonoids, polyphenols, organic sulphur, saponins and many other secondary metabolites which are mainly responsible for its medical activities Sohail et al.

Keywords: cultivars, blueberry, polyphenol, organic fertilizer, mineral fertilizer INTRO DUCTIO NT he fruits of blueberries have very positive effects on the human body. Characteristic of these fruits are their bioactive properties. T hey are an important source of polyphenolic compounds, flavonoids, especially anthocyanins and having high antioxidant activity. On the content of bioactive substances affect several factors, such as environmental conditions, degree of ripeness, variety, method of storage and processing. Polyphenols and phenol compounds represent one of the most numerous and most represented groups of plant metabolites and form part of the human diet . T hey are products of secondary metabolism of plants (Mandelová, 2005). Plant polyphenols are substances widespread in almost all plants, particularly in the leaves, flowers, seeds, fruits, and in pathology departments, as well as in products of plant origin (honey, propolis, wine). One group of polyphenols includes a wide and diverse range of compounds -from simple phenolic acids to high polymerized tannins. More than 8.000 phenolic compounds are known, but only a few hundred are identified in the edible parts of plants (Timoracká et al., 2008).

Phenolic compounds are the predominant antioxidants in nutrition and their study is currently being paid much attention. These antioxidants act synergistically; polyphenol compounds protect vitamin C and β-carotene, which in turn helps to increase the effect of vitamin E. Potatoes are very popular vegetables in Slovakia, not only in terms that they are easy to prepare, but also by the fact that they combine the wholesomeness of cereals and delicacy and characteristic chemical composition of vegetables. It is important that they find their place in our diet. Nutritional value of potatoes is determined by the content of nutrients such as protein, starch, fat, minerals, and absence of toxins, as well as by a significant content of bioactive components from the group of polyphenols. The study was performed in order to analyse 7 Slovak potato varieties from Spiš area, according to biologically active compounds: such as polyphenols. The content of total polyphenols was determined by the method of Lachman et al., (2003). The lowest determined content of total polyphenol (mg.kg-1 dry matter) in locality Spišský Štvrtok was measured in a variety Victoria (795.05 mg.kg-1 dry matter) and the highest content of total polyphenols in locality Spišský Štvrtok was measured in variety Laura (1238.42 mg.kg-1 dry matter). In the locality Odorín was determine the lowest content of total polyphenols in variety Red Anna (974.09 mg.kg-1 dry matter) and the highest content of total polyphenols was determined in variety Laura (978.95 mg.kg-1 dry matter). Between all varieties in locality Spišský Štvrtok was confirmed the statistically significant difference in the influence of the variety in the contents of total polyphenols (mg.kg-1 DM). This varietal dependence was not appear in samples taken in the locality Odorín. The total polyphenols content of the potatoes can be influenced by other factors, for example locality. In this case, there were statistically significant differences in the content of total polyphenols in variety Laura obtained from two different localities.