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  • Author: M. Baranová x
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Abstract

Extracts of the fruiting bodies of the Oyster mushroom (Pleurotus ostreatus) grown on wood substrates (beech, oak, linden, walnut, poplar) and extracts of the fruiting bodies of the Oyster mushroom (Pleurotus pulmonarius) grown in nature on aspen wood were used to determine the total phenols, total flavonoids, lycopene and β-carotene. The content of individual antioxidants varies considerably depending, not only on the substrate, but also on the extracting agents. The highest content of total phenols and total flavonoids was found in methanol and water extracts of the fruiting bodies of the Oyster mushrooms grown on oak and linden substrates. The maximum content of lycopene and β-carotene was determined in acetone and n-hexane (ratio 4 : 6) extracts of the fruiting bodies of the Oyster mushroom grown on an oak block. The results obtained in this study demonstrated that the quantitative and also probably the qualitative composition of the antioxidants in the fruiting bodies of Oyster mushrooms depended considerably on the substrate composition.

Abstract

The aim of this study was to investigate the distribution of the contents of iodine and selenium in selected food commodities. Fresh food commodities were mineralized and analysed for their iodine and selenium content by Inductively Coupled Plasma-Mass Spectrometry using the calibration curve as the method for determining the contents of the elements. The average fruit and vegetables concentrations of iodine were very low. The cow’s milk, other dairy products, eggs, poultry, fresh water fish, beef, liver, and mushrooms are frequently regarded as the most important natural source of dietary iodine from common foods. The higher concentrations of selenium were recorded in the kidney, liver, pork, beef, poultry, fresh water fish, hen’s eggs, cow’s milk, other dairy products, wheat flour, fats, coffee, peppers, mushrooms and potatoes.

Abstract

In this study we examined the dried fruiting bodies of Morchella esculenta, collected in the area of the coal and biomass based thermal power plant in Vojany from the nearby Bahoň marsh, in the Slovak Republic. The area is characterized by a high environmental burden, especially because of air pollutant emissions from the power plant operation. Twenty-three (23) chemical elements were found in the dried fruiting bodies after microwave-assisted sample preparation using an Inductively Coupled Plasma Mass Spectrophotometer ICP-MS AGILENT 7500c system. The mercury content was determined employing a special AMA 254 apparatus intended for the determination of Hg directly in dry powdered fruiting bodies without microwave digestion. The content of toxic elements expressed in mg.kg−1 DW (dry weight) were as follows: Hg 0.048—0.052 (RSD—Relative Standard Deviation = 4.80 %); Cd 4.543—6.169 (RSD = 3.35 %); Pb 0.261—0.291 (RSD = 2.67 %); As 0.455—0.469 (RSD = 5.79 %); Cr 1.585—1.616 (RSD = 2.33 %); and Ni 8.166—9.276 (RSD = 3.03 %). The contents of cadmium, nickel and mercury exceeded the hygiene limits, while the contents of arsenic and lead approached the hygiene limits. Due to the high levels of toxic elements, the fruiting bodies collected in the location are not suitable for culinary purposes. The mushroom Morchella esculenta acts as an accumulator of toxic elements from the environment in which it grows and can be considered as an indicator of environmental pollution.

Abstract

This study focused on the determination of non-specific proteolytic activity of edible spruce Morchella esculenta in water extract, phosphate-buffered saline (PBS) solution (pH = 7.5) extract and a suspension prepared from 200 mg DW (dry weight) of edible spruce in PBS solution (pH 7.5). A clear casein solution was used as a substrate. The absorbances were measured in quartz cuvettes at the wavelength of 280 nm against a blank with zero concentration of trypsin. Non-specific proteolytic activity was expressed as trypsin equivalents per kilogram of mushroom dry weight (mg.kg−1 DW). All of the extracts demonstrated non-specific enzymatic activity. The highest activity was observed in the PBS suspension and the lowest enzymatic activity was measured in the water extract of the Morchella esculenta fungi. The non-specific proteolytic activity decreased in the following order: PBS suspension extract (pH 7.5; 22.9 mg.kg−1 DW), followed by PBS extract (pH 7.5; 13.6 mg.kg−1 DW) and finally the water extract (10.94 mg.kg−1 DW).

Abstract

The aim of this study was to examine the content of chemical elements in the dried fruiting bodies of edible wood decaying fungi such as Honey mushrooms (Armillaria mellea), Shiitakes (Lentinus edodes) and Oyster mushrooms (Pleurotus ostreatus). Powdered samples of fungi were mineralized in a microwave digestion. Twenty-one (21) chemical elements were detected in the plasma of the device ICP-MS AGILENT 7500c by accredited methods with the aid of calibration curves. The content of individual elements varied within a considerable range. The highest contents of K, Mn, Cu and Cd were found in the fruiting bodies of Honey mushrooms (Armillaria mellea). Shiitakes (Lentinus edodes) had the highest content of B and Mo. Significant differences were found in the content of elements in the Oyster mushrooms (Pleurotus ostreatus) from Slovakia, Hungary and China. The highest content of Al was found in the Oyster mushrooms (Pleurotus ostreatus) from Hungary. The Chinese oysters had a maximum contents of Ca, Mg, Co, Pb, As and U. The Oyster mushrooms (Pleurotus ostreatus) from Lemešany (Slovakia) had the highest contents of Na, Zn, Fe, Se, Ag, Hg and Cr. The difference of chemical element content could be influenced by the genotype of the fungus and by the composition of substrate on which mushroom grow up.

Abstract

The paper deals with the mechanical properties of steel gas pipeline DN 500 after more than 40 years of operation. Mechanical properties of the pipeline were established by a tensile test at an ambient temperature according to the standard EN ISO 6892-1. The resistance of the pipeline against brittle failure was evaluated by using Charpy impact test according to EN 10045-1. The character of fracture surface after the Charpy test was analysed by using scanning electron microscopy. A high proportion of transcrystalline cleavage was a characteristic feature of fracture surfaces. Mechanical characteristics obtained by static tensile testing were compared with the values obtained from steel manufacturer. Higher elongation was observed in a parallel direction compared to the perpendicular direction to the axis of the pipe. The observed anisotropy of properties was related to the distribution of inclusions in the direction of the deformation of the steel sheets used for the pipeline construction.

Abstract

Mushrooms Basidiomycota have long been appreciated for their taste, flavour, desirable aroma, texture, nutraceutical and medicinal attributes. Honey mushrooms (Armillaria mellea) are edible mushroom generally used in traditional oriental medicine. The aim of this study was to examine extracts from the fruiting bodies of these mushrooms. The content of the components with antioxidant properties, such as total phenols, total flavonoids, β-carotene, lycopene and β-glucans were determined by spectrophotometric methods. The results obtained showed that the water extracts contained higher levels of total phenols and total flavonoids (367.1 and 548.5 mg.dm−3 gallic acid equivalent — GAE, respectively) in comparison with methanol extracts (108.2 and 113.4 mg.dm−3 GAE, respectively). Very low contents of β-carotene and lycopene were determined in the methanol extract (0.756 mg.g−1 dry weight and 0.05 mg.g−1 dry weight, respectively). Methanol extracts from the fruiting bodies of Honey mushrooms (Armillaria mellea) inhibited the uptake activity of 2,2-diphenylpicrylhydrazyl (DPPH) free radicals by 45 %. The IC50 (mg of compound, that inhibit 50 % of DPPH radicals) of methanol extract was below 10 mg.cm−3 (6.448 mg.cm−3), suggesting a high antioxidant potential of fruiting bodies of the Honey mushrooms Armillaria mellea.