Enrichment of Culinary-Medicinal Oyster Mushroom, Pleurotus ostreatus (Agaricomycetes), Cultivated on the Straw Substrate with Zinc and Selenium.

Pleurotus ostreatus was cultivated on a commercially available wheat straw substrate enriched with Zn and Se. Various amounts of Zn (10, 50, and 100 mg) and Se (1, 5, and 10 mg) in suitable forms ((CH3COO)2Zn·2H2O, Zn(NO3)2·6H2O, and Na2SeO3·5H2O, respectively) were dissolved in 50 ml of deionized water and homogenously nebulized into the substrate block of 2.4 kg weight. The increase in the Zn content in fruiting bodies cultivated on the enriched substrate was relatively low compared with fruiting bodies cultivated on the substrate with no addition at the first flush. The application of different Zn compounds (acetate vs. nitrate) gave similar results. However, the addition of 1 mg of Se into the cultivation substrate block increased the content of Se in fruiting bodies to about 3-6 mg/kg dry matter. This content was one order of magnitude higher compared with the Se content in fruiting bodies harvested from the substrate with no Se addition (< 0.12-0.58 mg/kg dry matter). In the case of the addition of 5 mg of Se, there was a further significant increase in the content of this element to about 40-60 mg/kg dry matter.

Determination of Detrimental and Essential Elements in Medicinal Mushrooms Tylopilus felleus, Auricularia auricula-judae, and Pleurotus ostreatus (Agaricomycetes).

In this study, selected detrimental and essential elements were determined in fruiting bodies of Auricularia auricula-judae, Tylopilus felleus, and Pleurotus ostreatus medicinal mushrooms. A. auricula-judae and T. felleus were collected from sampling sites situated in South Bohemia, the Czech Republic, while P. ostreatus samples were obtained after cultivation under defined conditions on a straw substrate block. The elements were determined in underlying soils for T. felleus and bioconcentration factors were calculated. The analysis revealed that T. felleus accumulated Rb, Cd, Cu, Zn, Se, and Mg, with bioconcentration factors of 65.7, 2.47, 2.32, 1.93, 1.67, and 1.27, respectively. The analysis also revealed high contents (expressed as medians) of Ca (1600 mg/kg) and Mg (2040 mg/kg) in A. auricula-judae. On the other hand, the contents of detrimental elements such as Pb (0.10 mg/kg), Cd (0.33 mg/kg), and As (0.10 mg/kg) were lower. In cultivated P. ostreatus, lower element contents for Pb (< 0.05 mg/kg), Al (3.92 mg/kg), Ca (53.6 mg/kg), Mn (3.22 mg/kg), Ni (0.11 mg/kg), and Sr (0.93 mg/kg) were determined compared to both wild-growing A. auricula-judae and T. felleus. No negative effect on human health is expected for the mushroom species studied due to the accumulation of detrimental microelements.

Detrimental and essential elements in fruiting bodies of wild-growing fungi Coprinus comatus, Flammulina velutipes, and Armillaria ostoyae.

Edible medicinal wild-growing fungi Coprinus comatus, Flammulina velutipes, and Armillaria ostoyae were analyzed with regard to the contents of 21 elements in their fruiting bodies. The samples were collected from selected sites in South Bohemia, the Czech Republic. C. comatus concentrated Ag, Cd, Cu, Se, and Rb with bioconcentration factors of 12, 2.5, 2.3, 1.8, and 1.1, respectively. High contents (all values expressed in mg kg-1 dry matter) of Al (260), Ca (480), Cu (61), Fe (340), Mg (1400), and Zn (86) were determined for this species. F. velutipes was characterized with markedly high contents of Ca (360), Fe (110), Mg (1200), Mn (26), and Zn (98), respectively. A considerably high content of Ag (5.6) was revealed for A. ostoyae. High contents of Ca (150), Cu (28), Fe (190), Mg (1100), Mn (30), and Zn (40) were determined in fruiting bodies of this species as well. The data concerning the detrimental elements in fruiting bodies of studied fungi indicate no considerably negative effect on human health if they are consumed as a delicacy or used in alternative medicine.

The three-year monitoring of 18 elements in five edible mushroom species collected from an old orchard.

The content of Al, As, Be, Cd, Ca, Cr, Co, Cu, Fe, Pb, Li, Mg, Mn, Ni, Rb, Se, Sr, and Zn in fruiting bodies of edible mushrooms Calocybe gambosa, Entoloma clypeatum, Entoloma saepium, Xerocomellus chrysenteron, and Amanita rubescens growing in an orchard planted with fruit trees and situated close to a high-grown forest was studied during years 2016-2018. A. rubescens showed the highest potential of the element accumulation with bioconcentration factors of 48.5, 16.2, 7.80, 6.53, 1.75, and 1.68 obtained for Rb, Cd, Cu, Zn, Sr, and Mg, respectively. Both Entoloma species accumulated the elements similarly with bioconcentration factors >1.0 obtained for Rb, Cu, Cd, and Mg. Bioconcentration factors <0.05 were obtained for Al, Cr, Fe, and Pb in all studied species. The contents of beryllium (<0.1 mg/kg dry matter) were always the lowest among the studied elements. The contents of some elements of studied mushroom species significantly fluctuated over the years. Despite the fact that some studied elements (As, Be, Cd, Pb, Ni) are considerably toxic for humans, the pronounced effect on health is not expected if the studied mushroom species are consumed occasionally and do not represent the main component of the diet.

The Accumulation of Risk and Essential Elements in Edible Mushrooms Chlorophyllum rhacodes, Suillus grevillei, Imleria badia, and Xerocomellus chrysenteron Growing in the Czech Republic.

Risk and essential elements were determined in fruiting bodies of wild growing edible mushrooms Chlorophyllum rhacodes, Suillus grevillei, Imleria badia, and Xerocomellus chrysenteron collected in an unpolluted site in South Bohemia, the Czech Republic. The elements were also determined in underlying soils and the bioconcentration factors were calculated. The analyses revealed that C. rhacodes accumulated Ag, Cu, Rb, Se, Zn, As, Cd, and Tl. On the other hand, S. grevillei accumulated Cd, Rb, Ag, Se, and Cs. I. badia and X. chrysenteron strongly accumulated Rb, Cs, and Ag; these species showed the ability to accumulate Cu and Zn as well. Contents of detrimental CrVI were in all cases below the quantification limit (0.003 mg kg-1 dry matter). Studied mushroom species (mainly C. rhacodes) accumulated some toxic elements. However, no considerable effect on human health is expected since they are usually consumed as a delicacy and do not represent a major component of diet.