Extraction of Ergothioneine from Pleurotus eryngii and P. citrinopileatus (Agaricomycetes) and Preparation of Its Product.

Ergothioneine is an effective antioxidant and is abundant in species of genus Pleurotus. This research focused on developing an ergothioneine extract from P. eryngii and P. citrinopileatus under optimal extraction conditions. The hot-water and 70% ethanol extractions yielded more ergothioneine than microwave, ultrasonic, and autoclaving extractions. Hot-water extraction with optimal conditions-125 rpm at 75°C for 5 minutes-produced P. eryngii and P. citrinopileatus extracts with 0.86 and 3.73 mg ergothioneine/g dry weight, respectively. In addition to 50% of added maltodextrin, spray-dried products from mushrooms contained 23.07-16.58% carbohydrates and 18.32-21.40% protein. The microstructure of spray-dried products showed shrunken spheres with mean particle diameters of 15.82-19.94 µm. After in vitro simulated gastric and intestinal digestion, the spray-dried P. eryngii and P. citrinopileatus products contained 88% and 91% residual ergothioneine, respectively. Overall, the spray-dried products could be used as antioxidative supplements.

Effect of Pulsed Light Irradiation on Bioactive, Nonvolatile Components and Antioxidant Properties of Caterpillar Medicinal Mushroom Cordyceps militaris (Ascomycetes).

The caterpillar medicinal mushroom Cordyceps militaris contains many bioactive components, such as adenosine, cordycepin, and polysaccharides. In this study, C. militaris was exposed to 0, 3, 6, or 9 pulses of light irradiation to estimate changes in vitamin D2, bioactive compounds, nonvolatile taste components, and antioxidant properties. In addition, we compared the components and properties of C. militaris mycelia and solid waste medium that had been treated with pulsed light (PL) irradiation. Overall, PL irradiation of C. militaris increased the vitamin D2 content and increased the total amino acid levels 9-48%; the antioxidant properties of the mycelia treated with 0 pulses and of the solid waste medium treated with 3 pulses all exhibited lower half-maximal effective concentrations. Therefore, PL irradiation affected the amounts of bioactive compounds, but the irradiated samples still contained intense umami taste and a sufficient amount of antioxidant components.

The Quality Improvement of Solid-State Fermentation with Cordyceps militaris by UVB Irradiation.

Cordyceps militaris, a medicinal and edible mushroom, was used to ferment buckwheat and embryo rice by solid-state fermentation (SSF). Our aim was to investigate the effect of ultraviolet B (UVB) light irradiation on the content of vitamin D2 and biologically effective components, and antioxidant properties of buckwheat and embryo rice in SSF with C. militaris. Irradiated samples of buckwheat and embryo rice fermented by C. militaris had significantly increased vitamin D2 content, from 0-0.3 to 1.18-16.79 µg/g, while the increase in fresh embryo rice fermented by C. militaris was up to 16.79 µg/g. The content of adenosine, cordycepin and polysaccharide in irradiated dry samples fermented by C. militaris was 0.08 to 11.15 mg/g, higher than that of the irradiated fresh samples fermented by C. militaris (0.07-8.40 mg/g). Samples fermented by C. militaris had lower EC50 values and higher content of antioxidants than did unfermented samples. When the solid-state fermented sample was irradiated with UVB light, the content of biologically effective and antioxidant components and antioxidant property of sample decreased. However, it still contained enough of these biologically effective and antioxidant components.

Effect of UV-B Irradiation on Physiologically Active Substance Content and Antioxidant Properties of the Medicinal Caterpillar Fungus Cordyceps militaris (Ascomycetes).

Ultraviolet-B (UV-B) light irradiation is a well-known technique for converting vitamin D2 from ergosterol in mushroom fruit bodies. Mushrooms are a natural and nonanimal food source of vitamin D2. We studied the effect of UV-B light irradiation on the amount of vitamin D2 and physiologically active substances in Cordyceps militaris and their antioxidant properties. After UV-B irradiation for 2 hours, the vitamin D2 content of freshly harvested C. militaris fruiting bodies, mycelia, whole submerged culture (WSC), and homogenized submerged culture (HSC) increased from 0 to 0.03 to 0.22 to 1.11 mg/g, but the ergosterol content was reduced from 1.36 to 2.50 to 1.24 to 2.06 mg/g, respectively. After UV-B irradiation, the amount of adenosine, cordycepin, and ergothioneine of fruiting bodies dramatically increased 32-128%, but the polysaccharide content slightly decreased 36%. The reverse trends were observed in mycelia, WSC, and HSC. UV-B irradiation could reduce the effective concentrations at 50% of fruiting bodies for ethanolic and hot water extracts in reducing power, scavenging, and chelating abilities, whereas mycelia, WSC, and HSC of ethanolic extracts increased effective concentrations at 50% in reducing power, scavenging, and chelating abilities. UV-B irradiation slightly increased flavonoid content (10-56%) and slightly affected total phenol content.

Enhancement of antioxidant properties and increase of content of vitamin D2 and non-volatile components in fresh button mushroom, Agaricus bisporus (higher Basidiomycetes) by γ-irradiation.

Agaricus bisporus is a popular culinary-medicinal mushroom in Taiwan, and γ-irradiation could extend its shelf life. Our objective was to study the content of vitamin D2 and the taste components and antioxidant properties of ethanolic extracts from A. bisporus with various doses of γ-irradiation. After irradiation, the vitamin D2 content of 5-10 kGy irradiated mushrooms was in the range of 5.22-7.90 µg/g, higher than that of the unirradiated control (2.24 µg/g). For all treatments, the total content of soluble sugars and polyols ranged from 113 to 142 mg/g, and the monosodium glutamate-like components ranged from 6.57 to 13.50 mg/g, among which the 2.5 kGy irradiated sample has the highest content of flavor 5'-nucleotide. About antioxidant properties, 10 kGy irradiated samples exhibited lower EC50 values than did other samples. EC50 values were less than 5 mg/mL for ethanolic extracts. Total phenols were the major antioxidant components and the total content was 13.24-22.78 mg gallic acid equivalents/g. Based on the results obtained, γ-irradiation could be used to improve the vitamin D2 content and intensity of umami taste in fresh mushrooms. In addition, γ-irradiation not only maintained the antioxidant properties of mushrooms but also enhanced the antioxidant properties to some extent.

Nonvolatile taste components of culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.:Fr.) S.F. Gray.

Culinary-medicinal maitake mushroom Grifola frondosa (Dicks.: Fr.) S.F. Gray mycelium was inoculated into wheat, a new product was formed after fungal fermentation, and its nonvolatile taste components were studied. Contents of crude ash, fat, fiber, and protein were higher in fruit bodies and mycelia, whereas carbohydrate contents were higher in the uninoculated and fermented wheat. Contents of total soluble sugars and polyols were 234.06, 111.70, 88.58, and 28.83 mg/g for fermented wheat, fruiting bodies, mycelia, and wheat, respectively. Contents of total free amino acids were in the descending order of mycelia > fermented wheat > fruiting bodies > wheat. Contents of total 5'-nucleotides were in the descending order: fruiting bodies > mycelia > fermented wheat > wheat. Based on the results obtained, fruiting bodies and mycelia possessed highly intense umami taste. Overall, as a result of solid-state fermentation, fermented wheat contained more taste components and a higher equivalent umami concentration than wheat did.

Preparation of culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.: Fr.) S.F. Gray (Aphyllophoromycetideae)-fermented wheat and its antioxidant properties.

The optimization of solid-state fermentation conditions for mycelial growth in wheat by culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.: Fr.) S.F. Gray was studied. The results from the center of the design analysis showed that the recommended optimal conditions for carbon, nitrogen sources, and temperature were 19 mg lactose/g, 2.0 mg malt extract/g, and 30 degrees C, respectively. Under these conditions, the mycelial biomass of 533.1 mg/g was obtained in fermented wheat, comparable to that (545.7 mg/g) obtained using the one-factor-at-a-time method. Based on the results obtained, EC50 values of ethanolic and hot water extracts from fermented wheat were 1.13-15.27 mg/mL, indicating that fermented wheat was effective in antioxidant activity, reducing power, scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, and chelating ability on ferrous ions. Total phenol contents of both extracts were 13.35 and 23.01 mg/g, respectively. Accordingly, the information obtained would be applicable for the cultivation and consumption of G. frondosa-fermented wheat to provide its beneficial health effects.