Enhancement of the antioxidants ergothioneine and selenium in Pleurotus eryngii var. eryngii basidiomata through cultural practices

Abstract

Antioxidants are molecules that may reverse, prevent or slow cellular damage caused by free radicals. Increasing dietary intake of antioxidants is thought to reduce oxidative stress that may contribute to the development of several diseases. Mushrooms are known to contain antioxidants such as selenium, ergothioneine and phenolics that may serve this role. Here we sought to enhance selenium and ergothioneine concentration in Pleurotus eryngii var. eryngii basidiomata by modifying the techniques used for their commercial cultivation. To enhance selenium content in mushrooms, substrates were supplemented with sodium selenite (Na 2 SeO 3 ) to reach selenium concentrations of 5 and 10 lg/g. Basidiomata of one commercial isolate (WC888) accumulated selenium up to 4.6 and 9.3 lg/g (d.w.), respectively. Therefore, a serving size (85 g) of fresh P. eryngii mushrooms produced on substrates supplemented with 5 and 10 lg/g of Na 2 SeO 3 would supply 70.4 and 116.3% of the daily value of selenium (DV = 70 lg), respectively. Since selenium-enriched mushrooms would supply more than 20% of the DV, they could be considered an excellent source of selenium. Ergothioneine concentration was enhanced in mushrooms produced on low-moisture (55%) substrate compared to the commonly used 60% (high-moisture) in commercial cultivation. Mushrooms produced on low-moisture substrate had ergothioneine concentrations of 3.0 mg/g, while mushrooms produced on high-moisture substrate contained 2.2 mg/g or less. Use of a casing overlay for mushroom production resulted in significant yield increases on lowmoisture substrate but not on high-moisture substrate.

Phenolic composition and antioxidant properties of Pleurotus ostreatus and Pleurotus eryngii enriched with selenium and zinc

“…The Se concentration in non-enriched P. ostreatus (control) was 2.73 ± 0.26 mg/ Inhibition (%) = (A − A C )/A × 100. [21,25,26,29]. In our experiment, after Se and Zn enrichment substrates possessed higher mineral availability for fruiting bodies and it influenced the micronutrient accumulation in mushrooms.…”

“…Se is a component of antioxidant enzymes via amino acid (selenocysteine, selenomethionine) and proteins [21][22][23]. Zn is a component of enzymes participating in the synthesis and degradation of different biomolecules including lipids, proteins, carbohydrates and nucleic acids as well as in the metabolism of other micronutrients [19].…”

“…The deficiency of micronutrient is associated with health disturbances, and thus, different cultivation practices have been successfully implemented to increase the nutritional value of mushrooms [21,25,26]. It was also documented that enrichment with micronutrients had an impact on antioxidant activities and phenolic content [26][27][28].…”

Macro and trace mineral constituents and radionuclides in mushrooms: health benefits and risks

“…Compost fortified with inorganic Se (Na 2 SeO 3 ) at a rate of 8.1 and 14.4 mg kg has been used, and the Se-enriched Pleurotus eryngii contained, respectively, 4.6 and 9.3 mg Se kg −1  dm (<1.5 mg kg −1  dm in reference fruit bodies) (Estrada et al 2009). …”

Antioxidant Properties of Selected Boletus Mushrooms

“…15 Mushrooms have powerful antioxidant properties derived from compounds such as selenium, ergothioneine, and phenolics. 16 Selenium is a component of the antioxidant enzymes selenoproteins. This proteins help in the prevention of cellular damage that free radicals can induce.…”