Enhancing the Extraction Yield from Shiitake Culinary-Medicinal Mushroom, Lentinus edodes (Agaricomycetes), by Pulsed Electric Fields Treatment

Medicinal mushrooms contain highly valuable substances with proven positive effects on human health. To extract these components, different methods are available. Most of them suffer from individual disadvantages, therefore making them economically unviable. Pulsed electric fields (PEFs) could provide an opportunity to improve these processes. PEFs cause pore formation of cell membranes, facilitating substance transport out of cells. Thus, the influence of this technique on the extraction yield of medicinal mushrooms was studied for the first time. Lentinus edodes was used as model case and PEF treatment was compared with standard Soxhlet extraction alone. A square pulse generator (Electro Square Porator™ ECM 830) with a voltage of 3 kV and pulse length of 100 μs was used for PEF treatment. Extraction was studied for fresh and dried fruiting bodies, and dichloromethane and hot water extracts were analyzed. Extracts were quantified gravimetrically, and carbohydrate yields were also determined qualitatively with GC-MS and quantitatively with anthrone method. PEFs could increase in particular the yield of water-soluble compounds of fresh mushroom material. However, the lipid fraction was not affected by PEF in neither fresh nor dried material.