Antioxidant properties of methanolic extracts from several ear mushrooms.

Five kinds of ear mushrooms are commercially available in Taiwan, including black, red, jin, snow, and silver ears. Methanolic extracts were prepared from these ear mushrooms, and their antioxidant properties were studied. For all methanolic extracts from ear mushrooms, the antioxidant activities in the 1,3-diethyl-2-thiobarbituric acid method were moderate (38.6 approximately 74.6%) at 1.0-5.0 mg/mL. Methanolic extracts from red, jin, and snow ears showed excellent antioxidant activities in the conjugated diene method at 5.0 mg/mL. At 5.0 mg/mL, reducing powers of methanolic extracts were in the descending order of snow > black approximately red approximately jin > silver ears. The scavenging effect of methanolic extracts from ear mushrooms on 1,1-diphenyl-2-picrylhydrazyl radicals was excellent except for that from silver ears. Ear mushroom extracts were not good scavengers for hydroxyl free radicals but were good chelators for ferrous ions. Naturally occurring antioxidants, including ascorbic acid, tocopherols, and total phenols, were found in the methanolic extracts. However, beta-carotene was not detected. Total antioxidant components were 15.69, 30.09, 27.83, 49.17, and 31.70 mg/g for black, red, jin, snow, and silver ears, respectively.     

Antioxidant properties of several medicinal mushrooms

Three species of medicinal mushrooms are commercially available in Taiwan, namely, Ganoderma lucidum (Ling-chih), Ganoderma tsugae (Sung-shan-ling-chih), and Coriolus versicolor (Yun-chih). Methanolic extracts were prepared from these medicinal mushrooms and their antioxidant properties studied. At 0.6 mg/mL, G. lucidum, G. lucidum antler, and G. tsugae showed an excellent antioxidant activity (2.30-6.41% of lipid peroxidation), whereas C. versicolor showed only 58.56%. At 4 mg/mL, reducing powers were in the order G. tsugae (2.38) approximately G. lucidum antler (2.28) > G. lucidum (1.62) > C. versicolor (0.79). At 0.64 mg/mL, scavenging effects on the 1,1-diphenyl-2-picrylhydrazyl radical were 67.6-74.4% for Ganoderma and 24.6% for C. versicolor. The scavenging effect of methanolic extracts from G. lucidum and G. lucidum antler on hydroxyl radical was the highest (51.2 and 52.6%) at 16 mg/mL, respectively. At 2.4 mg/mL, chelating effects on ferrous ion were in the order G. lucidum antler (67.7%) > G. lucidum (55.5%) > G. tsugae (44.8%) > C. versicolor (13.2%). Total phenols were the major naturally occurring antioxidant components found in methanolic extracts from medicinal mushrooms. Overall, G. lucidum and G. tsugae were higher in antioxidant activity, reducing power, scavenging and chelating abilities, and total phenol content.     

Chemical composition and biological properties of portuguese wild mushrooms: a comprehensive study

The chemical composition and biological properties of Portuguese wild mushrooms ( Cantharellus cibarius, Hypholoma fasciculare, Lepista nuda, Lycoperdon molle, Lycoperdon perlatum, Ramaria botrytis, Tricholoma acerbum) were evaluated in order to assess these products as sources of nutrients and nutraceuticals. The analyzed mushrooms contain very useful phytochemicals such as phenolics, tocopherols, ascorbic acid, and carotenoids. All of the species proved to have antioxidant activity (measured by four different methods), being more significant for R. botrytis (EC 50 values < 1 mg/mL). Lycoperdon species were resistant to all of the tested microorganisms, and the other samples revealed antimicrobial activity selectively against Gram-positive bacteria, with very low minimal inhibitory concentration, in some cases, even lower than the standard. The combination of bioactive compounds and rich nutritional composition (high contents in protein and carbohydrates, low content in fat with the precious contribution of unsaturated fatty acids and the absence of trans fatty acids) in the mushroom makes it a very special food.     

Antioxidant activity of indigenous edible mushrooms

The current study was undertaken to measure the antioxidant potential from water and methanolic extracts of fruiting bodies of 23 species of mushrooms naturally grown in different geographic locations of India. The antioxidant ability of each species was analyzed for the total antioxidative status, employing multimechanistic antioxidative assays such as inhibition of lipid peroxidation, determination of reducing power, and free radical scavenging ability, in addition to determination of total phenolics and identification of phenolic acids by HPLC analysis, because the phenolics are known to contribute largely to antioxidant potential. The antioxidant potential of these varieties of mushrooms was determined by summing the antioxidative activity (AOA) of each variety by varied antioxidant assays followed by determining the relative percent of AOA defined as the "antioxidant index" (AI). On the basis of the AI, the mushroom species were graded as very high, high, moderate, and low. Termitomyces heimii was identified as the best variety, which showed 100% AI with 37 mg of phenolics/g of sample, 418 units of reducing power ability (RPA)/g, and an IC50 of approximately 1.1 mg (dry weight)/mL, free radical scavenging activity (FRS) in the water extract followed by 11.2 mg of phenolics/g, 275 units of RPA/g, and an IC50 of approximately 2.7 mg (dry weight)/mL of FRS in the methanolic extract. Following T. heimii, Termitomyces mummiformis exhibited an AI of 86% within the "very high" group. Potent inhibitions of lipid peroxidation of approximately 100 and 69% was also observed in T. heimii and T. mummiformis, respectively. Water extracts ranged from 34 to 49% and methanolic extracts varied from 20 to 32% on dry weight of mushroom fruiting body. Total phenolic compounds were higher in the water extracts (2-37 mg/g) than in methanolic extract (0.7-11.2 mg/g). The AOA measured in the water extract was better than that from the methanolic extract. HPLC analysis of phenolic acids in the two mushroom species, namely, T. heimii and T. mummiformis, displaying maximum AOA potential indicated a preponderance of tannic acid, gallic acid, protocatacheuic acid, and gentisic acid. Studies thus provide the precise antioxidant status of 23 indigenous species of mushrooms, which can serve as a useful database for the selection of mushrooms for the function of preparation of mushroom-based nutraceutics.     

Phenolic, polysaccharidic, and lipidic fractions of mushrooms from northeastern Portugal: chemical compounds with antioxidant properties

Mushrooms do not constitute a significant portion of the human diet, but their consumption continues to increase due to their functional benefits and presence of bioactive compounds. Some of those compounds can be found in the phenolic, polysaccharidic, and lipidic fractions of edible and inedible species. Herein, those fractions of five wild mushrooms (Coprinopsis atramentaria, Lactarius bertillonii, Lactarius vellereus, Rhodotus palmatus, and Xerocomus chrysenteron) from northeastern Portugal were studied for their chemical composition and antioxidant properties. Protocatechuic, p-hydroxybenzoic, p-coumaric, and cinnamic acids were found in the phenolic fraction; rhamnose, xylose, fucose, arabinose, fructose, glucose, manose, mannitol, sucrose, maltose, and trehalose were quantified in polysaccharidic fraction; and linoleic and stearic (only in Lactarius sp.) acids, and β- and γ-tocopherols were the main compounds in the lipidic fraction. C. atramentaria and X. chrysenteron phenolic fractions gave the highest free radical scavenging activity, reducing properties, and lipid peroxidation inhibition in brain homogenates, which is in agreement with its highest content in total phenolics. Furthermore, among the polysaccharidic fractions C. atramentaria also gave the highest antioxidant activity, which is in agreement with its highest total polysaccharides content and sugars obtained after hydrolysis.     

Quantitation of nine organic acids in wild mushrooms

The organic acids composition of six wild edible mushroom species (Amanita caesarea, Boletus edulis, Gyroporus castaneus, Lactarius deliciosus, Suillus collinitus, and Xerocomus chrysenteron) was determined by an HPLC-UV detector method. The results showed that all of the samples presented a profile composed of at least five organic acids: citric, ketoglutaric, malic, succinic, and fumaric acids. Several samples also contained oxalic, ascorbic, quinic, and shikimic acids. In a general way, the quantitation of the identified compounds indicated that malic acid, followed by the pair citric plus ketoglutaric acids, were the main compounds in the analyzed species, with the exception of A. caesarea, in which malic and ascorbic acids were the most abundant compounds. The relative amounts and the presence/absence of each identified compound may be useful for the differentiation of the species.     

Vitamin D mushrooms: comparison of the composition of button mushrooms (Agaricus bisporus) treated postharvest with UVB light or sunlight

This study compared the compositional changes in mushrooms exposed to sunlight with those occurring after commercial ultraviolet (UV) light processing. Button mushrooms (75 kg) were processed in the presence or absence of UVB light; a third group was exposed to direct sunlight. Mushroom composition was evaluated using chemical analyses. Vitamin D concentrations were 5, 410, and 374 μg/100 g (dw) in control, UVB, and sunlight groups, respectively. On a dry weight basis, no significant changes in vitamin C, folate, vitamins B(6), vitamin B(5), riboflavin, niacin, amino acids, fatty acids, ergosterol, or agaritine were observed following UVB processing. Sunlight exposure resulted in a 26% loss of riboflavin, evidence of folate oxidation, and unexplained increases in ergosterol (9.5%). It was concluded that compositional effects of UVB light are limited to changes in vitamin D and show no detrimental changes relative to natural sunlight exposure and, therefore, provide important information relevant to the suitability and safety of UVB light technology for vitamin D enhanced mushrooms.     

Cadmium-resistant oyster mushrooms from North China for mycoremediation

Macrofungi have been advocated to be a promising remediation material for heavy metal pollution. This study aimed to screen for cadmium(Cd)-tolerant oyster mushroom strains which may be used as biomaterials for Cd remediation in North China. To this end, 43 oyster mushroom strains were collected across North China and subject to Cd inhibition test. Phylogenetic affiliation of the tolerant strains was identified using molecular fingerprinting, and representative Cd-tolerant strains were characterized in terms of their Cd sorption capacity. Two strains, JINONG21 and SUYIN6 affiliated with Pleurotus ostreatus, were found to be highly tolerant to Cd, with a minimal inhibitory concentration of 4 mg L~(-1) Cd and a maximal tolerant concentration of 80 mg L~(-1) Cd under the test conditions. Meanwhile, JINONG21 and SUYIN6 were able to absorb up to 676 mg kg~(-1) and 970 mg kg~(-1) Cd in their mycelia in the culture medium with 20 mg L~(-1) Cd, respectively. In conclusion, the P. ostreatus strains identified in this study presented an outstanding capacity of Cd tolerance and sorption and could be promising biomaterials for Cd remediation in North China.     

Characterization of tyrosinase from the cap flesh of portabella mushrooms

Tyrosinase, purified from the cap flesh tissue of portabella mushrooms, was characterized with regard to its physical and biochemical properties. A native molecular size of 41 kDa for the enzyme was obtained by size exclusion chromatography, whereas SDS-PAGE indicated that the enzyme contained a single subunit with a size of approximately 48 kDa under reduced and nonreduced conditions. The purified enzyme showed a single immunological cross-reacting protein after Western blotting when probed with antibodies against Agaricus bisporus tyrosinase. Isoelectric focusing demonstrated that the enzyme preparation, apparently homogeneous by electrophoresis, still contained three isoforms of pI 5.1, 5.2, and 5.3. The purified enzyme was able to oxidize a variety of mono-, di-, and triphenolic compounds. An apparent K(m) of 5 mM was obtained using catechol as the substrate, and an apparent K(m) of 9 mM was found using L-Dopa as a substrate. Ascorbic acid, kojic acid, tropolone, mercaptobenzothiazole, and salicylhydroxamic acid inhibited the enzyme severely at 100 microM.     

Effect of fruiting body maturity stage on chemical composition and antimicrobial activity of Lactarius sp. mushrooms

The effects of fruiting body maturity on chemical composition and antimicrobial activity of the wild mushrooms, Lactarius deliciosus and Lactarius piperatus, were evaluated. Immature and mature samples were analyzed for proximate constituents (moisture, fat, crude protein, ash, carbohydrates), nutritional value, and individual composition in fatty acids and sugars. Protein content, MUFA (monounsaturated fatty acids), and PUFA (polyunsaturated fatty acids) percentages increased with the fruiting body maturity stage, while carbohydrate and SFA (saturated fatty acids) content decreased. The maturity stage did not significantly affect the individual sugar profile. The antimicrobial activity of the mushrooms was screened against Gram positive and Gram negative bacteria and fungi, and correlated to the amounts of phenols, flavonoids, ascorbic acid, beta-carotene, and lycopene present in the immature and mature fruiting bodies. Mature fruiting bodies with mature spores presented lower antimicrobial activity, which was in agreement with the bioactive compound content found in those samples.     

Acylhomoserine lactone production by bacteria associated with cultivated mushrooms

The main bacterial pathogens of cultivated mushroom as well as mushroom-associated bacteria, which were isolated from Agaricus bisporus, Pleurotus ostreatus and Pleurotus eryngii mushroom niches, were evaluated for the production of N-acyl-L-homoserine lactones (AHLs) by using four bioreporters. Furthermore, identification of AHLs by LC-ESI-FTICR MS was performed on culture filtrates of selected pathogens and mushroom-associated bacteria strains, which resulted in inducing at least one of the four bioreporters. Strains of Burkolderia gladioli pv. agariciola, Pseudomonas agarici and Pseudomonas gingeri, but not those of Pseudomonas tolaasii and Pseudomonas reactans, produced an array of AHLs depending on the strain. This is the first report of AHL production by mushroom bacterial pathogens. Forty-four of 236 bacterial isolates obtained from different niches of cultivated mushrooms, in part identified by the Biolog identification system, were demonstrated to produce AHLs. Among them, seven mushroom-associated bacterial species were for the first time demonstrated to produce the above signal molecules. In the culture filtrates of a certain number of isolates/strains the AHL-hydrolyzed forms were also present. The minimal signal inducing concentration (MSIC) of selected pure AHLs was also determined for the four bioreporters used in this study.     

双孢菇微波冷冻干燥特性及干燥品质

为获得干燥时间短、产品质量高的蘑菇制品,采用微波冷冻干燥技术对双孢菇进行干燥处理,研究其在不同微波比功率(0.25,0.5,0.75 W/g)和系统压强(50,100,150 Pa)下的干燥曲线、有效水分扩散系数、复水比、收缩率、白度、维生素C保存率、能耗及基于模糊数学推理法下感官评定的变化规律;通过非线性拟合建立了适用于双孢菇微波冷冻干燥的数学模型;基于干燥能耗、干燥时间及部分品质指标对不同条件下双孢菇微波冷冻干燥过程进行加权综合评价。结果表明:微波比功率对干燥速率及干制品物理品质指标影响比对其他指标的影响更显著(P0.05);系统压强对干制品营养含量指标、干燥能耗以及感官评定的影响比对干燥特性的影响显著(P0.05);采用Henderson and Pabis模型能够准确(R20.9)描述干燥过程中水分变化规律;双孢菇有效水分扩散系数在10-10 m2/s数量级且受微波比功率影响更明显(P0.05);微波比功率和系统压强过高会造成双孢菇干制产品不被消费者接受;当微波比功率和系统压强分别为0.25 W/g和100 Pa时双孢菇微波冷冻干燥的综合评分值最高为0.67847,该条件较适合应用于双孢菇微波冷冻干燥中。研究探索了不同微波冷冻干燥条件下双孢菇干燥及品质特性的变化规律,为双孢菇微波冷冻干燥较优工艺参数组合的选择提供了理论依据。     

High processing tolerances of immunomodulatory proteins in Enoki and Reishi mushrooms

This study investigated the processing tolerances of two mushroom proteins with immunomodulatory activities, including FVE from Enoki ( Flammulia velutipes ) and LZ8 from Reishi ( Ganoderma lucidum ) mushrooms, under food processing treatments such as heating, sterilization, frozen storage, extraction in acid/alkaline conditions, and dehydration. Results showed that the capability of these two proteins to induce IFN-gamma secretion by murine splenocytes remained after 100 degrees C heating for 30 min, 121 degrees C autoclaving for 15 min, and -80 degrees C freezing. The retained activities of both proteins on cell proliferation and IFN-gamma production did not decrease at 0.6 M hydrochloric acid (at pH 2) but strikingly dropped at 5 M sodium hydrate (at pH 13). After vacuum dehydration, FVE and LZ8 retained most of their activities on cell proliferation; nevertheless, the IFN-gamma secretion decreased to about half of the initial values. These findings suggest that these two mushroom proteins have a good thermal/freezing resistance, acid tolerance, and dehydration stability and are candidates for processing in food and nutraceutical utilization.     

Simultaneous determination of thiamin and riboflavin in mushrooms by liquid chromatography

A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determination of thiamin and riboflavin in mushrooms is examined. It uses the extraction procedure, with slight modifications, proposed by the AOAC for the extraction of thiamin and riboflavin, followed by a liquid chromatographic separation on a reversed-phase Spherisorb ODS column with methanol/water as mobile phase gradient. Fluorometric detection is used at the following excitation and emission wavelengths, respectively, 360 and 425 nm in the case of thiamin and 422 and 515 nm for riboflavin. The analytical parameters of linearity, the precision of the method (RSD = 2.45 and 2.51% for thiamin and riboflavin, respectively), and the results of the comparison with the corresponding AOAC fluorometric methods show that the studied method is useful for the measurement of thiamin and riboflavin in fresh mushrooms.     

Basic composition and amino acid contents of mushrooms cultivated in Finland

The basic composition (moisture, total carbohydrates, dietary fiber, crude fat, ash, nitrogen, and protein) and amino acid contents were determined in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinula edodes, and Pleurotus ostreatus. In addition, nitrogen-to-protein conversion factors were calculated for each species by dividing the sums of amino acid residues with total (Kjeldahl) nitrogen contents. The dry matter contents of mushrooms varied from 7.7% to 8.4%. The dry matter of mushrooms contained large amounts of carbohydrates, from 4.5 (A. bisporus/white) to 5.8 g/100 g fresh weight (L. edodes). L. edodes proved to be an especially good source of dietary fiber (3.3 g/100 g fresh weight); the other mushrooms contained 1.5-2.4 g/100 g fresh weight. Crude fat, ash, and protein (based on amino acid analysis) contents of the mushrooms varied 0.31-0.35, 0.49-0.78, and 1.8-2.09 g/100 g fresh weight, respectively. Mushrooms proved to be good sources of almost all essential amino acids when compared with common vegetables. The mean nitrogen-to-protein conversion factor analyzed in the present study was 4.7 +/- 0.21. When using this factor, a very good estimation of protein contents could be obtained for the main species of mushrooms cultivated in Finland.     

Characterization of phytase activity from cultivated edible mushrooms and their production substrates

Phytase is used commercially to maximize phytic acid degradation and to decrease phosphorus levels in poultry and swine manure. To determine phytase content in edible mushrooms, basidiomata of Agaricus bisporus and three specialty mushrooms (Grifola frondosa, Lentinula edodes, and Pleurotus cornucopiae) and spent mushroom substrate (SMS) were surveyed. Enzyme activity ranged from 0.046 to 0.074 unit/g of tissue for four A. bisporus types (closed and open whites and closed and open browns) grown at The Pennsylvania State University's Mushroom Test Demonstration Facility (MTDF). The addition of various nutrient supplements to phase II mushroom production substrate did not alter phytase activity in A. bisporus. Portabella mushrooms (open brown) obtained from a commercial farm had significantly higher levels of phytase activity (0.211 unit/g of tissue) compared to A. bisporus grown at the MTDF. Of the specialty mushrooms surveyed, maitake (G. frondosa) had 20% higher phytase activity (0.287 unit/g of tissue) than commercial portabella mushrooms. The yellow oyster mushroom (P. cornucopiae) ranked second in level of phytase activity (0.213 unit/g of tissue). Shiitake (L. edodes) contained the least amount of phytase in basidiomata (0.107 unit/g of tissue). Post-crop steam treatment (60 degrees C, 24 h) of SMS reduced phytase activity from 0.074 to 0.018 unit/g. Phytase was partially purified from commercially grown portabella basidiomata 314-fold with an estimated molecular mass of 531 kDa by gel filtration chromatography. The optimum pH for activity was 5.5, but appreciable phytase activity was observed over the range of pH 5.0-8.0. Partially purified A. bisporus phytase was inactivated following a 10-min incubation at > or =60 degrees C.     

Phenolic compound concentration and antioxidant activities of edible and medicinal mushrooms from Korea

A study was conducted to determine the content of phenolic compounds and the antioxidative activity of five edible and five medicinal mushrooms commonly cultivated in Korea. Phenolic compounds were analyzed using high performance liquid chromatography, and antioxidant activity was evaluated by 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and superoxide dismutase activity. A total of 28 phenolic compounds were detected in the mushrooms studied. The average total concentration of phenolic compounds was 326 microg/g, the average being of 174 microg/g in edible mushrooms and 477 microg/g in medicinal mushrooms. The average total flavonoids concentration was 49 microg/g, with averages of 22 and 76 microg/g in edible and medicinal mushrooms, respectively. The DPPH radical scavenging activities ranged between 15 (Pleurotus eryngii) and 70% (Ganoderma lucidum) when reaction time was for 1 min. When reaction time was 30 min, the values ranged between 5 (Pleurotus eryngii) and 78% (Agaricus bisporus). The SOD activity averaged 28% among the 10 mushroom species, averages for edible and medicinal mushrooms being comparable. DPPH activities was significantly correlated (p < 0.01) with total content of phenolic compounds in edible mushrooms, while in medicinal mushrooms there was a significant correlation (p < 0.01) between SOD activity and total concentration of phenolic compounds. Numerous significant positive correlations were observed between phenolic compounds detected and antioxidative potential.     

Contents of vitamins, mineral elements, and some phenolic compounds in cultivated mushrooms

The aim of the study was to determine the contents of mineral elements (Ca, K, Mg, Na, P, Cu, Fe, Mn, Cd, Pb, and Se), vitamins (B(1), B(2), B(12), C, D, folates, and niacin), and certain phenolic compounds (flavonoids, lignans, and phenolic acids) in the cultivated mushrooms Agaricus bisporus/white, Agaricus bisporus/brown, Lentinus edodes, and Pleurotus ostreatus. Selenium, toxic heavy metals (Cd, Pb), and other mineral elements were analyzed by ETAAS, ICP-MS, and ICP methods, respectively; vitamins were detected by microbiological methods (folates, niacin, and vitamin B(12)) or HPLC methods (other vitamins), and phenolic compounds were analyzed by HPLC (flavonoids) or GC--MS methods (lignans and phenolic acids). Cultivated mushrooms were found to be good sources of vitamin B(2), niacin, and folates, with contents varying in the ranges 1.8--5.1, 31--65, and 0.30--0.64 mg/100 g dry weight (dw), respectively. Compared with vegetables, mushrooms proved to be a good source of many mineral elements, e.g., the contents of K, P, Zn, and Cu varied in the ranges 26.7--47.3 g/kg, 8.7--13.9 g/kg, 47--92 mg/kg, and 5.2--35 mg/kg dw, respectively. A. bisporus/brown contained large amounts of Se (3.2 mg/kg dw) and the levels of Cd were quite high in L. edodes (1.2 mg/kg dw). No flavonoids or lignans were found in the mushrooms analyzed. In addition, the phenolic acid contents were very low.     

音乐与蟋蟀鸣声的混合声频对食用菌生长的影响

为了考察声波对食用菌生长、产量及营养成分等方面的影响,采用自行开发的声频设备,播放古典音乐与蟋蟀鸣声混合而成的声频,对茶树菇、高温姬菇、黑平、杏鲍菇、秀珍菇、小白菇等6种食用菌的菌丝体进行了7次声波助长试验,对姬菇、黑平和姬菇18号3种食用菌的子实体进行了4次试验。结果表明,此声频可使食用菌的菌丝体生长速度加快10.2%～21%;使子实体提早出菇,提前1～5 d采菇,并可延长采菇天数;4次子实体试验的产量分别增加了15.76%、13.38%、13.05%和7.95%。经对2种子实体成分检测比较表明,姬菇18号的脂肪、蛋白质和粗多糖质量分数分别增加5.88%、8.74%和2.78%,黑平的蛋白质、粗多糖的质量分数分别提高2.37%和43.27%。研究结果为声波助长技术在食用菌生产上的推广应用提供科学依据。