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

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 (Na₂SeO₃) to reach selenium concentrations of 5 and 10 μg/g. Basidiomata of one commercial isolate (WC888) accumulated selenium up to 4. 6 and 9. 3 μg/g (d. w.), respectively. Therefore, a serving size (85 g) of fresh P. eryngii mushrooms produced on substrates supplemented with 5 and 10 μg/g of Na₂SeO₃ would supply 70. 4 and 116. 3% of the daily value of selenium (DV = 70 μg), 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 low-moisture substrate but not on high-moisture substrate.