Determination of Mineral Components in the Cultivation Substrates of Edible Mushrooms and Their Uptake into Fruiting Bodies

The mineral contents of the cultivation substrates, fruiting bodies of the mushrooms, and the postharvest cultivation substrates were determined in cultivated edible mushrooms Pleurotus eryngii, Flammulina velutipes, and Hypsizigus marmoreus. The major mineral elements both in the cultivation substrates and in the fruiting bodies were K, Mg, Ca, and Na. Potassium was particularly abundant ranging 10${\sim}$13 g/kg in the cultivation substrates and 26${\sim}$30 g/kg in the fruiting bodies. On the contrary, the calcium content in the fruiting bodies was very low despite high concentrations in the cultivation substrates, indicating Ca in the cultivation substrates is in a less bio-available form or the mushrooms do not have efficient Ca uptake channels. Among the minor mineral elements determined in this experiment, Cu, Zn, and Ni showed high percentage of transfer from the cultivation substrates to the fruiting bodies. It is noteworthy that the mineral contents in the postharvest cultivation substrates were not changed significantly which implies that the spent cultivation substrates are nutritionally intact in terms of mineral contents and thus can be recycled as mineral sources and animal feeds.