Boletus edulis (English: cep, penny bun, porcino or porcini) is a basidiomycete fungus, and the type species of the genus Boletus. Widely distributed in the Northern Hemisphere across Europe, Asia, and North America, it does not occur naturally in the Southern Hemisphere, although it has been introduced to southern Africa, Australia, New Zealand, and Brazil. Several closely related European mushrooms formerly thought to be varieties or forms of B.edulis have been shown using molecular phylogenetic analysis to be distinct species, and others previously classed as separate species are conspecific with this species. The western North American species commonly known as the California king bolete (Boletus edulis var. grandedulis) is a large, darker-coloured variant first formally identified in 2007.
The fungus grows in deciduous and coniferous forests and tree plantations, forming symbioticectomycorrhizal associations with living trees by enveloping the tree's underground roots with sheaths of fungal tissue. The fungus produces spore-bearing fruit bodies above ground in summer and autumn. The fruit body has a large brown cap which on occasion can reach 30cm (12in), rarely 40cm (16in) in diameter and 3kg (6lb 10oz) in weight. Like other boletes, it has tubes extending downward from the underside of the cap, rather than gills; spores escape at maturity through the tube openings, or pores. The pore surface of the B.edulis fruit body is whitish when young, but ages to a greenish-yellow. The stout stipe, or stem, is white or yellowish in colour, up to 20cm (8in), rarely 30cm (12in) tall and 10cm (4in) thick, and partially covered with a raised network pattern, or reticulations.
Prized as an ingredient in various culinary dishes, B.edulis is an edible mushroom held in high regard in many cuisines, and is commonly prepared and eaten in soups, pasta, or risotto. The mushroom is low in fat and digestible carbohydrates, and high in protein, vitamins, minerals and dietary fibre. Although it is sold commercially, it is very difficult to cultivate. Available fresh in autumn throughout Europe and Russia, it is most often dried, packaged, and distributed worldwide. It keeps its flavour after drying, and it is then reconstituted and used in cooking. B.edulis is also one of the few fungi sold pickled.
Taxonomy
Pierre Bulliard first described B.edulis in 1782.
Boletus edulis was first described in 1782 by the French botanist Pierre Bulliard and still bears its original name.[3] The starting date of fungal taxonomy had been set as January1, 1821, to coincide with the date of the works of the 'father of mycology', Swedish naturalist Elias Magnus Fries, which meant the name required sanction by Fries (indicated in the name by a colon) to be considered valid, as Bulliard's work preceded this date. It was thus written Boletus edulis Bull.:Fr. A 1987 revision of the International Code of Botanical Nomenclature set the starting date at May1, 1753, the date of publication of Linnaeus' work, the Species Plantarum.[4] Hence, the name no longer requires the ratification of Fries' authority. Early alternate names include Boletus solidus by English naturalist James Sowerby in 1809,[5] and Gray'sLeccinum edule.[6] Gray's transfer of the species to Leccinum was later determined to be inconsistent with the rules of botanical nomenclature, and he apparently was unfamiliar with the earlier works of Fries when he published his arrangement of bolete species.[7]
Boletus edulis is the type species of the genus Boletus. In Rolf Singer's classification of the Agaricales mushrooms, it is also the type species of sectionBoletus, a grouping of about 30 related boletes united by several characteristics: a mild-tasting, white flesh that does not change colour when exposed to air; a smooth to distinctly raised, netted pattern over at least the uppermost portion of the stem; a yellow-brown or olive-brown spore print; white tubes that later become yellowish then greenish, which initially appear to be stuffed with cotton; and cystidia that are not strongly coloured.[8][9]Molecular analysis published in 1997 established that the bolete mushrooms are all derived from a common ancestor, and established the Boletales as an order separate from the Agaricales.[10]
The generic name is derived from the Latin term bōlētus "mushroom", which was borrowed in turn from the Ancient Greek βωλίτης, "terrestrial fungus".[11] Ultimately, this last word derives from bōlos/βῶλος "lump", "clod", and, metaphorically, "mushroom".[12] The βωλίτης of Galen, like the boletus of Latin writers like Martial, Seneca and Petronius,[13] is often identified as the much prized Amanita caesarea.[14] The specific epithetedulis in Latin means "eatable" or "edible".[15]
Common names
Common names for B. edulis vary by region. The standard Italian name, porcino (pl. porcini), means porcine;[16]fungo porcino, in Italian, echoes the term suilli, literally "hog mushrooms", a term used by the Ancient Romans[17] and still in use in southern Italian terms for this species.[18] The derivation has been ascribed to the resemblance of young fruit bodies to piglets, or to the fondness pigs have for eating them.[19] It is also known as "king bolete".[20] The English penny bun refers to its rounded brownish shape. The German name Steinpilz (stone mushroom) refers to the species' firm flesh.[21] In Austria, it is called Herrenpilz, the "noble mushroom",[19] while in Mexico, the Spanish name is panza, meaning "belly".[22] Another Spanish name, rodellon, means "small round boulder", while the Dutch name eekhoorntjesbrood means "squirrel's bread".[23] Russian names are belyy grib (ru:белый гриб; "white mushroom" as opposed to less valuable "black mushrooms") and borovik (ru:боровик; from bor—"pine forest"). The vernacular name cep is derived from the Catalancep or its French name cèpe, although the latter is a generic term applying to several related species. In France, it is more fully cèpe de Bordeaux, derived from the Gasconcep "trunk" for its fat stalk,[24] ultimately from the Latincippus "stake".[25]Ceppatello, ceppatello buono, ceppatello bianco, giallo leonato, ghezzo, and moreccio are names from Italian dialects,[26][27] and ciurenys or surenys is another term in Catalan.[28] The French-born King Charles XIV John popularised B.edulis in Sweden after 1818,[29] and is honoured in the local vernacular name Karljohanssvamp, as well as the Danish name Karl Johan svamp. The monarch cultivated the fungus about his residence, Rosersberg Palace.[30] The Finnish name is herkkutatti, from herkku 'delicacy', and tatti, 'bolete'.
Description
Cross-section showing white flesh, broad stem, and spore tubes on the underside of the cap
The cap of this mushroom is 7–30cm (3–12in) broad at maturity. Slightly sticky to touch, it is convex in shape when young and flattens with age. The colour is generally reddish-brown fading to white in areas near the margin, and continues to darken as it matures. The stipe, or stem, is 8–25cm (3–10in) in height, and up to 7cm (3in) thick—rather large in comparison to the cap;[31] it is club-shaped, or bulges out in the middle. It is finely reticulate on the upper portion, but smooth or irregularly ridged on the lower part. The under surface of the cap is made of thin tubes, the site of spore production; they are 1 to 2cm (1⁄2 to 3⁄4in) deep, and whitish in colour when young, but mature to a greenish-yellow.[32] The angular pores, which do not stain when bruised, are small—roughly 2 to 3 pores per millimetre.[33] In youth, the pores are white and appear as if stuffed with cotton (which are actually mycelia); as they age, they change colour to yellow and later to brown. The spore print is olive brown. The flesh of the fruit body is white, thick and firm when young, but becomes somewhat spongy with age. When bruised or cut, it either does not change colour, or turns a very light brown or light red.[34] Fully mature specimens can weigh about 1kg (2lb 3oz); a huge specimen collected on the Isle of Skye, Scotland, in 1995 bore a cap of 42cm (16+1⁄2in), with a stipe 18cm (7in) in height and 14cm (5+1⁄2in) wide, and weighed 3.2kg (7lb 1oz).[31] A similarly sized specimen found in Poland in 2013 made international news.[35]
Stem shape can range from club-shaped to centrally bulbous
Boletus edulis is considered one of the safest wild mushrooms to pick for the table, as few poisonous species closely resemble it, and those that do may be easily distinguished by careful examination.[19] The most similar poisonous mushroom may be the devil's bolete (Rubroboletus satanas), which has a similar shape, but has a red stem and stains blue on bruising.[19] It is often confused with the very bitter and unpalatable Tylopilus felleus, but can be distinguished by the reticulation on the stalk; in porcini, it is a whitish, net-like pattern on a brownish stalk, whereas it is a dark pattern on white in the latter. Porcini have whitish pores while the other has pink. If in doubt, tasting a tiny bit of flesh will yield a bitter taste.[19] It can also resemble the "bolete-like" Gyroporus castaneus, which is generally smaller, and has a browner stem. Boletus huronensis, an uncommon mushroom of northeastern North America, is another recognized look-alike known to cause severe gastrointestinal disorders.[36]
The spores are elliptical to spindle-shaped, with dimensions of 12–17 by 5–7μm. The basidia, the spore-bearing cells, are produced in a layer lining the tubes, and arrange themselves so their ends are facing the center of the tube; this layer of cells is known technically as a hymenium. The basidia are thin-walled, mostly attached to four spores, and measure 25–30 by 8–10μm. Another cell type present in the hymenium is the cystidia, larger sterile cells that protrude beyond the basidia into the lumen of the hymenium, and act as air traps, regulating humidity.[37]B.edulis has pleurocystidia (cystidia located on the face of a pore) that are thin-walled, roughly spindle-shaped to ventricose, and measure 30–45 by 7–10μm; the "stuffed" feature of the hymenium is caused by cheilocystidia—cells found on the edges of the pores.[32] The hyphae of B.edulis do not have clamp connections.[33]
Related species
B. edulis var. grandedulis
B. regineus
Several similar brownish-coloured species are sometimes considered subspecies or forms of this mushroom. In Europe, in addition to B.edulis (or cèpe de Bordeaux), the most popular are:
Cèpe bronzé ("dark cep"; Boletus aereus), much rarer than B.edulis, is more highly regarded by gourmets, and consequently more expensive. Usually smaller than B.edulis, it is also distinctively darker in colour.[19] It is especially suited to drying.[20]
Cèpe des pins ("pine tree cep"; Boletus pinophilus or Boletus pinicola) grows among pine trees. Rarer than B.edulis, it is less appreciated by gourmets than the two other kinds of porcini, but remains a mushroom rated above most others.[20]
Molecular phylogenetic analyses have proven these three are all distinctive and separate species;[38] other taxa formerly believed to be unique species or subspecies, such as B.betulicola, B.chippewaensis, B.persoonii, B.quercicola and B.venturii, are now known to be part of a B.edulisspecies complex with a wide morphological, ecological and geographic range,[39][40] and that the genetic variability in this complex is low.[41] Similar molecular technology has been developed to rapidly and accurately identify B.edulis and other commercially important fungi.[42][43]
Three divergent lineages found in Yunnan province in China that are commonly marketed and sold as B. edulis (and are actually more closely related to B. aereus) were described in 2013 as B. bainiugan, B. meiweiniuganjun and B. shiyong.[44][45] The classification has since been updated and expanded. All lineages are still members of Boletus sect. Boletus, the sensu sticto "porcini clade" of the genus.[46]
B. rex-veris
Western North America has several species closely related to B.edulis. The white king bolete (Boletus barrowsii), found in parts of Colorado, New Mexico, Arizona, and California (and possibly elsewhere), is named after its discoverer Chuck Barrows.[47] It is lighter in colour than B.edulis, having a cream-coloured cap with pink tones;[48] often mycorrhizal with Ponderosa pine, it tends to grow in areas where there is less rainfall. Some find its flavour as good as if not better than B.edulis.[49] The California king bolete (Boletus edulis var. grandedulis) can reach massive proportions, and is distinguished from B.edulis by a mature pore surface that is brown to slightly reddish. The cap colour appears to be affected by the amount of light received during its development, and may range from white in young specimens grown under thick canopy, to dark-brown, red-brown or yellow brown in those specimens receiving more light.[50] The queen bolete (Boletus regineus), formerly considered a variety of B.aereus, is also a choice edible. It is generally smaller than B.edulis, and unlike that species, is typically found in mixed forests.[51] The spring king bolete (Boletus rex-veris), formerly considered a variety of B.edulis or B.pinophilus, is found throughout western North America. In contrast to B.edulis, B.rex-veris tends to fruit in clusters, and, as its common name suggests, appears in the spring.[52]B.fibrillosus is edible but considered inferior in taste.[53]
Habitat and distribution
In Lithuania
The fruit bodies of Boletus edulis can grow singly or in small clusters of two or three specimens. The mushroom's habitat consists of areas dominated by pine (Pinus spp.), spruce (Picea spp.), hemlock (Tsuga spp.) and fir (Abies spp.) trees, although other hosts include chestnut, chinquapin, beech, Keteleeria spp., Lithocarpus spp., and oak. In California, porcini have been collected in a variety of forests, such as coastal forests, dry interior oak forests and savannas and interior high-elevation montanemixed forests,[54] to an altitude of 3,500m (11,500ft).[55] In northwestern Spain, they are common in scrublands dominated by the rock rose species Cistus ladanifer and Halimium lasianthum.[56] In the Midi region of south-west France, they are especially favoured and locally called cèpe de Bordeaux after the town from which they are traded to the north and abroad.[57]
Boletus edulis has a cosmopolitan distribution, concentrated in cool-temperate to subtropical regions.[54] It is common in Europe—from northern Scandinavia, south to the extremities of Greece and Italy—and North America, where its southern range extends as far south as Mexico.[34] It is well known from the Borgotaro area of Parma, Italy, and has PGI status there. The European distribution extends north to Scandinavia and south to southern Italy and Morocco.[54] In the American Pacific Northwest, it can be found from May to October.[58] In China, the mushroom can be found from the northeastern Heilongjiang to the Yunnan–Guizhou Plateau and Tibet.[34] It has been recorded growing under Pinus and Tsuga in Sagarmatha National Park in Nepal,[59] as well as in the Indian forests of Arunachal Pradesh.[60] In West Asia, the species has been reported from the northwest forests of Iran.[61]
Cultivation
Some steps have been made towards cultivating Boletus edulis,[62] including mycorrhization of rockrose shrubs enhanced by helper bacteria.[63]
Non-native introductions
Boletus edulis grows in some areas where it is not believed to be indigenous. It is often found underneath oak and silver birch in Hagley Park in central Christchurch, New Zealand, where it is likely to have been introduced,[64] probably on the roots of container-grown beech, birch, and oak in the mid-19th century—around the time exotic trees began to be planted in the Christchurch area.[34] Similarly, it has been collected in Adelaide Hills region of Australia in association with three species of introduced trees.[65] It has been growing plentifully in association with pine forests in the southern KwaZulu-Natal Midlands in South Africa for more than 50 years and is believed to have been introduced with the import of pine trees.[66][67] It also grows in pine plantations in neighboring Zimbabwe.[68]
Ecology
B. edulis is ectomycorrhizal and may co-occur with Pinus radiata
Italian folklore holds that porcini sprout up at the time of the new moon;[19] research studies have tried to investigate more scientifically the factors that influence the production of fruit bodies. Although fruit bodies may appear any time from summer to autumn (June to November in the UK), their growth is known to be triggered by rainfall during warm periods of weather followed by frequent autumn rain with a drop in soil temperature.[54] Above average rainfall may result in the rapid appearance of large numbers of boletes, in what is known in some circles as a "bolete year".[69] A 2004 field study indicated that fruit body production is enhanced by an open and sunny wood habitat,[70] corroborating an earlier observation made in a Zimbabwean study;[68] removal of the litter layer on the forest floor appeared to have a negative effect on fruit body production, but previous studies reported contradictory results.[71][72] A Lithuanian study conducted in 2001 concluded that the maximal daily growth rate of the cap (about 21mm or 0.8in) occurred when the relative air humidity was the greatest, and the fruit bodies ceased growing when the air humidity dropped below 40%. Factors most likely to inhibit the appearance of fruit bodies included prolonged drought, inadequate air and soil humidity, sudden decreases of night air temperatures, and the appearance of the first frost.[73] Plots facing north tend to produce more mushrooms compared to equivalent plots facing south.[74]
Mycorrhizal associations
Boletus edulis is mycorrhizal—it is in a mutualistic relationship with the roots of plants (hosts), in which the fungus exchanges nitrogen and other nutrients extracted from the environment for fixed carbon from the host. Other benefits for the plant are evident: in the case of the Chinese chestnut, the formation of mycorrhizae with B.edulis increases the ability of plant seedlings to resist water stress, and increases leaf succulence, leaf area, and water-holding ability.[75] The fungus forms a sheath of tissue around terminal, nutrient-absorbing root tips, often inducing a high degree of branching in the tips of the host, and penetrating into the root tissue, forming, to some mycologists, the defining feature of ectomycorrhizal relationships, a hartig net.[76] The ectomycorrhizal fungi are then able to exchange nutrients with the plant, effectively expanding the root system of the host plant to the furthest reaches of the symbiont fungi.[76] Compatible hosts may belong to multiple families of vascular plants that are widely distributed throughout the Northern Hemisphere; according to one 1995 estimate, there are at least 30 host plant species distributed over more than 15 genera.[34] Examples of mycorrhizal associates include Chinese red pine,[77]Mexican weeping pine,[78]Scots pine, Norway spruce,[79]Coast Douglas-fir,[80]mountain pine,[81] and Virginia pine.[82] The fungus has also been shown to associate with gum rockrose, a pioneer early stage shrub that is adapted for growth in degraded areas, such as burned forests.[83] These and other rockrose species are ecologically important as fungal reservoirs, maintaining an inoculum of mycorrhizal fungi for trees that appear later in the forest regrowth cycle.[84]
The mushroom has been noted to often co-occur with Amanita muscaria or A.rubescens, although it is unclear whether this is due to a biological association between the species, or because of similarities in growing season, habitat, and ecological requirements.[54] An association has also been reported between B.edulis and Amanita excelsa on Pinus radiata ectomycorrhizae in New Zealand, suggesting that other fungi may influence the life cycle of porcini.[85] A 2007 field study revealed little correlation between the abundance of fruit bodies and presence of its mycelia below ground, even when soil samples were taken from directly beneath the mushroom; the study concluded that the triggers leading to formation of mycorrhizae and production of the fruit bodies were more complex.[86]
Heavy-metal contamination
Boletus edulis is known to be able to tolerate and even thrive on soil that is contaminated with toxic heavy metals, such as soil that might be found near metal smelters. The mushroom's resistance to heavy-metal toxicity is conferred by a biochemical called a phytochelatin—an oligopeptide whose production is induced after exposure to metal.[87] Phytochelatins are chelating agents, capable of forming multiple bonds with the metal; in this state, the metal cannot normally react with other elements or ions and is stored in a detoxified form in the mushroom tissue.
Pests and predators
The fruit bodies of B.edulis can be infected by the parasitic mould-like fungus Hypomyces chrysospermus, known as the bolete eater, which manifests itself as a white, yellow, or reddish-brown cottony layer over the surface of the mushroom.[88] Some reported cases of stomach ache following consumption of dried porcini have been attributed to the presence of this mould on the fruit bodies.[89] The mushroom is also used as a food source by several species of mushroom flies,[54] as well as other insects and their larvae.[90] An unidentified species of virus was reported to have infected specimens found in the Netherlands and in Italy; fruit bodies affected by the virus had relatively thick stems and small or no caps, leading to the name "little-cap disease".[91][92]
A porcini mushroom and noodle soup served in a bread bowl at a Polish restaurantA porcini mushroom sandwich in Stockholm, Sweden
Boletus edulis, as the species epithetedulis (Latin: edible) indicates, is an edible mushroom. Italian chef and restaurateur Antonio Carluccio has described it as representing "the wild mushroom par excellence", and hails it as the most rewarding of all fungi in the kitchen for its taste and versatility.[19] Considered a choice edible, particularly in France, Germany, Poland and Italy,[20] it was widely written about by the Roman writers Pliny the Elder and Martial, although ranked below the esteemed Amanita caesarea. When he was served suilli[lower-alpha 1] instead of boleti,[98] the disgruntled Martial wrote:
sunt tibi boleti; fungos ego sumo suillos (Ep. iii. 60) ("You eat the choice boletus, I have mushrooms that swine grub up.")[99]
The flavour of porcini has been described as nutty and slightly meaty, with a smooth, creamy texture, and a distinctive aroma reminiscent of sourdough. Young, small porcini are most appreciated, as the large ones often harbour maggots (insect larvae), and become slimy, soft and less tasty with age. The fruit bodies are collected by holding the stipe near the base and twisting gently. Cutting the stipe with a knife may risk the part left behind rotting and the mycelium being destroyed. Peeling and washing are not recommended.[19] The fruit bodies are highly perishable, due largely to the high water content (around 90%), the high level of enzyme activity, and the presence of a flora of microorganisms.[100] Caution should be exercised when collecting specimens from potentially polluted or contaminated sites, as several studies have shown that the fruit bodies can bioaccumulate toxic heavy metals like mercury,[101]cadmium,[102]caesium and polonium.[103][104] Bioaccumulated metals or radioactive fission decay products are like chemical signatures: chemical and radiochemical analysis can be used to identify the origin of imported specimens,[105] and for long-term radioecological monitoring of polluted areas.[106]
Porcini are sold fresh in markets in summer and autumn in Europe and Russia, and dried or canned at other times of the year, and distributed worldwide to countries where they are not otherwise found.[107] They are eaten and enjoyed raw, sautéed with butter, ground into pasta, in soups, and in many other dishes. In France, they are used in recipes such as cèpes à la Bordelaise, cèpe frits and cèpe aux tomates.[108] Porcini risotto is a traditional Italian autumn dish.[109] Porcini are a feature of many cuisines, including Provençal,[110] and Viennese.[111] In Thailand they are used in soups and consumed blanched in salads.[112] Porcini can also be frozen, either while raw or after cooking in butter. The colour, aroma, and taste of porcini deteriorate noticeably after being frozen for four months. Blanching (or soaking and blanching) as a processing step before freezing can extend the freezer life to 12 months.[100] They are also one of the few species sold commercially as pickled mushrooms.[113]
Dried
A pile of dried porcini at the Borgotaro porcino festival in Italy
Boletus edulis is well suited to drying—its flavour intensifies, it is easily reconstituted, and its resulting texture is pleasant.[114] Reconstitution is done by soaking in hot, but not boiling, water for about twenty minutes; the water used is infused with the mushroom aroma and it too can be used in subsequent cooking. Dried porcini have more protein than most other commonly consumed vegetables, apart from soybeans. Some of their protein is indigestible, though digestibility is improved with cooking.[115]
Like other boletes, porcini can be dried by being strung separately on twine and hung close to the ceiling of a kitchen. Alternatively, the mushrooms can be dried by cleaning with a brush (washing is not recommended), and then placing them in a wicker basket or bamboo steamer on top of a boiler or hot water tank.[116] Another method is drying in an oven at 25 to 30°C (77 to 86°F) for two to three hours, then increasing the temperature to 50°C (122°F) until crisp or brittle.[117] Once dry, they must be kept in an airtight container.[116] Importantly for commercial production, porcini retain their flavour after industrial preparation in a pressure cooker or after canning or bottling, and are thus useful for manufacturers of soups or stews. The addition of a few pieces of dried porcino can significantly add to flavour, and they are a major ingredient of the pasta sauce known as carrettiera (carter's sauce).[118] The drying process is known to induce the formation of various volatile substances that contribute to the mushroom's aroma. Chemical analysis has shown that the odour of the dried mushroom is a complex mixture of 53 volatile compounds.[119]
Commercial harvest
Porcini can vary considerably in size.
A 1998 estimate suggested that the total annual worldwide consumption of Boletus edulis and closely related species (B.aereus, B.pinophilus, and B.reticulatus) was between 20,000 and 100,000 tons.[54] Approximately 2,700tonnes (3,000tons) were sold in France, Italy and Germany in 1988, according to official figures. The true amount consumed far exceeds this, as the official sales figures did not account for informal sales or consumption by collectors.[55] They are widely exported and sold in dried form, reaching countries where they do not occur naturally, such as Australia and New Zealand. The autonomous community of Castile and León in Spain produces 7,700tonnes (8,500tons) annually.[83] In autumn, the price of porcini in the Northern Hemisphere typically ranges between $20 and $80per kilogram, although in New York in 1997 the wholesale price rose to more than $200 per kilogram due to scarcity.[55]
In the vicinity of Borgotaro in the Province of Parma of northern Italy, the four species Boletus edulis, B.aereus, B.aestivalis and B.pinophilus have been recognised for their superior taste and officially termed Fungo di Borgotaro. Here these mushrooms have been collected for centuries and exported commercially. Owing to the globalization of the mushroom trade most of the porcini commercially available in Italy or exported by Italy no longer originate there. Porcini and other mushrooms are also imported into Italy from various locations, especially China and eastern European countries; these are then often re-exported under the "Italian porcini" label.[120][121]
In Italy the disconnect with local production has had an adverse effect on quality; for example in the 1990s some of the dried porcino mushrooms exported to Italy from China contained species of genus Tylopilus, which are rather similar in appearance and when dried are difficult for both mushroom labourers and mycologists alike to distinguish from Boletus. Tylopilus species typically have a very bitter taste, which is imparted to the flavour of the porcini with which they are mixed.[122]
After the fall of the Iron Curtain and the subsequent reduction of economic and political barriers, central and eastern European countries with local mushroom harvesting traditions, such as Albania, Bulgaria, Macedonia, Romania, Serbia and Slovenia, developed into exporters of porcini, concentrating primarily on the Italian market.[121] Porcini and other wild fungi from these countries are also destined for France, Germany and other western European markets, where demand for them exists but collection on a commercial scale does not.[121] Picking B.edulis has become an annual seasonal income earner and pastime in countries like Bulgaria, especially for many Roma communities and the unemployed.[123] A lack of control of the harvest has led to heavy exploitation of the mushroom resource.[124]
Like many other strictly mycorrhizal fungi, B.edulis has eluded cultivation attempts for years.[115][125][62] The results of some studies suggest that unknown components of the soil microflora might be required for B.edulis to establish a mycorrhizal relationship with the host plant.[126][127][128] Successful attempts at cultivating B.edulis have been made by Spanish scientists by mycorrhization of Cistus species,[62] with Pseudomonasfluorescens bacteria helping the mycorrhiza.[63]
Boletus edulis mushrooms are 9% carbohydrates, 3% fat, and 7% protein (table). Fresh mushrooms consist of over 80% moisture,[132] although reported values tend to differ somewhat as moisture content can be affected by environmental temperature and relative humidity during growth and storage.[133] The carbohydrate component contains the monosaccharidesglucose, mannitol and α,α-trehalose, the polysaccharideglycogen, and the water-insoluble structural polysaccharide chitin, which accounts for up to 80–90% of dry matter in mushroom cell walls. Chitin, hemicellulose, and pectin-like carbohydrates—all indigestible by humans—contribute to the high proportion of insoluble fibre in B.edulis.[134]
A comparative study of the amino acid composition of eleven Portuguese wild edible mushroom species showed Boletus edulis to have the highest total amino acid content.[136][137]
Aroma compounds giving B. edulis mushrooms their characteristic fragrance include some 100 components, such as esters and fatty acids.[147] In a study of aroma compounds, 1-octen-3-one was the most prevalent chemical detected in raw mushrooms, with pyrazines having increased aroma effect and elevated content after drying.[148]
The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface, instead of gills as are found in most agarics. Nearly as widely distributed as the agarics, the family is renowned for hosting some prime edible species highly sought after by mushroom hunters worldwide, such as the cep or king bolete . A number of rare or threatened species are also present in the family, that have become the focus of increasing conservation concerns. As a whole, the typical members of the family are commonly known as boletes.
Suillus luteus is a bolete fungus, and the type species of the genus Suillus. A common fungus native all across Eurasia from Ireland to Korea, it has been introduced widely elsewhere, including North and South America, southern Africa, Australia and New Zealand. Commonly referred to as slippery jack or sticky bun in English-speaking countries, its names refer to the brown cap, which is characteristically slimy in wet conditions. The fungus, initially described as Boletus luteus by Carl Linnaeus in 1753, is now classified in a different fungus family as well as genus. Suillus luteus is edible, though not as highly regarded as other bolete mushrooms. It is commonly prepared and eaten in soups, stews or fried dishes. The slime coating, however, may cause indigestion if not removed before eating. It is often sold as a dried mushroom.
Tylopilus felleus, commonly known as the bitter bolete or the bitter tylopilus, is a fungus of the bolete family. Its distribution includes east Asia, Europe and eastern North America, extending south into Mexico and Central America. A mycorrhizal species, it grows in deciduous and coniferous woodland, often fruiting under beech and oak. Its fruit bodies have convex to flat caps that are some shade of brown, buff or tan and typically measure up to 15 cm (6 in) in diameter. The pore surface is initially white before turning pinkish with age. Like most boletes it lacks a ring and it may be distinguished from Boletus edulis and other similar species by its unusual pink pores and the prominent dark-brown net-like pattern on its stalk.
Boletus aereus, commonly known as the dark cep, bronze bolete, or queen bolete, is a highly prized and much sought-after edible mushroom in the family Boletaceae. The bolete is widely consumed in Spain, France, Italy, Greece, and generally throughout the Mediterranean. Described in 1789 by French mycologist Pierre Bulliard, it is closely related to several other European boletes, including B. reticulatus, B. pinophilus, and the popular B. edulis. Some populations in North Africa have in the past been classified as a separate species, B. mamorensis, but have been shown to be phylogenetically conspecific to B. aereus and this taxon is now regarded as a synonym.
Chalciporus piperatus, commonly known as the peppery bolete, is a small pored mushroom of the family Boletaceae found in mixed woodland in Europe and North America. It has been recorded under introduced trees in Brazil, and has become naturalised in Tasmania and spread under native Nothofagus cunninghamii trees. A small bolete, the fruit body has a 1.6–9 cm orange-fawn cap with cinnamon to brown pores underneath, and a 4–9.5 cm high by 0.6–1.2 cm thick stipe. The flesh has a very peppery taste. The rare variety hypochryseus, found only in Europe, has yellow pores and tubes.
Boletus reticulatus, and commonly referred to as the summer cep is a basidiomycete fungus of the genus Boletus. It occurs in deciduous forests of Europe, where it forms a symbiotic mycorrhizal relationship with species of oak (Quercus). The fungus produces fruiting bodies in the summer months which are edible and popularly collected. The summer cep was formally described by Jacob Christian Schäffer as Boletus reticulatus in 1774, which took precedence over B. aestivalis as described by Jean-Jacques Paulet in 1793.
Suillus bovinus, also known as the Jersey cow mushroom or bovine bolete, is a pored mushroom of the genus Suillus in the family Suillaceae. A common fungus native to Europe and Asia, it has been introduced to North America and Australia. It was initially described as Boletus bovinus by Carl Linnaeus in 1753, and given its current binomial name by Henri François Anne de Roussel in 1806. It is an edible mushroom, though not highly regarded.
Suillellus luridus, commonly known as the lurid bolete, is a fungus of the family Boletaceae, found in calcareous broadleaved woodlands in Europe. Fruit bodies appear in summer and autumn and may be locally abundant. It is a firm bolete with an olive-brown cap up to 20 cm (8 in) in diameter, with small orange or red pores on the underside. The stout ochre stem reaches 8–14 cm (3–6 in) high and 1–3 cm (0.4–1.2 in) wide, and is patterned with a red network. Like several other red-pored boletes, it stains blue when bruised or cut.
Boletus barrowsii, also known in English as the white king bolete after its pale colored cap, is an edible and highly regarded fungus in the genus Boletus that inhabits western North America. Found under ponderosa pine and live oak in autumn, it was considered a color variant of the similarly edible B. edulis for many years.
Boletus pinophilus, commonly known as the pine bolete or pinewood king bolete, is a basidiomycete fungus of the genus Boletus found throughout Europe and western Asia. Described by Italian naturalist Carlo Vittadini in 1835, B. pinophilus was for many years considered a subspecies or form of the porcini mushroom B. edulis before genetic studies confirmed its distinct status. In 2008, B. pinophilus in western North America were reclassified as a new species, B. rex-veris. B. pinophilus is edible, and may be preserved and cooked.
Xerocomus subtomentosus, commonly known as suede bolete, brown and yellow bolete , boring brown bolete or yellow-cracked bolete, is a species of bolete fungus in the family Boletaceae. The fungus was initially described by Carl Linnaeus in 1753 and known for many years as Boletus subtomentosus. It is edible, though not as highly regarded as other bolete mushrooms.
Suillus variegatus, commonly called the velvet bolete or variegated bolete, is a species of edible mushroom in the genus Suillus. Like all bolete-like species it has tubes, and pores, instead of gills under its cap. The mushroom forms a mycorrhizal relationship with pine and occurs in North America and Eurasia.
Boletus rex-veris, commonly known as the spring king bolete, is a basidiomycete fungus of the genus Boletus found in western North America. The large, edible fruiting bodies known as mushrooms appear under pine trees, generally in May to June. It has a pinkish to brownish cap and its stem is often large and swollen, and the overall colour may have an orange-red tinge. As with other boletes, the size of the fruiting body is variable. Boletus rex-veris is edible, and may be preserved and cooked.
Exsudoporus frostii, commonly known as Frost's bolete or the apple bolete, is a bolete fungus first described scientifically in 1874. A member of the family Boletaceae, the mushrooms produced by the fungus have tubes and pores instead of gills on the underside of their caps. Exsudoporus frostii is distributed in the eastern United States from Maine to Georgia, and in the southwest from Arizona extending south to Mexico and Costa Rica. A mycorrhizal species, its fruit bodies are typically found growing near hardwood trees, especially oak.
Aureoboletus mirabilis, commonly known as the admirable bolete, the bragger's bolete, and the velvet top, is an edible species of fungus in the Boletaceae mushroom family. The fruit body has several characteristics with which it may be identified: a dark reddish-brown cap; yellow to greenish-yellow pores on the undersurface of the cap; and a reddish-brown stem with long narrow reticulations. Aureoboletus mirabilis is found in coniferous forests along the Pacific Coast of North America, and in Asia. Unusual for boletes, A. mirabilis sometimes appears to fruit on the wood or woody debris of Hemlock trees, suggesting a saprobic lifestyle. Despite the occasional appearances to the contrary, Aureoboletus mirabilis is mycorrhizal, and forms a close association with the tree's roots.
Suillus brevipes is a species of fungus in the family Suillaceae. First described by American mycologists in the late 19th century, it is commonly known as the stubby-stalk or the short-stemmed slippery Jack. The fruit bodies (mushrooms) produced by the fungus are characterized by a chocolate to reddish-brown cap covered with a sticky layer of slime, and a short whitish stipe that has neither a partial veil nor prominent, colored glandular dots. The cap can reach a diameter of about 10 cm, while the stipe is up to 6 cm long and 2 cm thick. Like other bolete mushrooms, S. brevipes produces spores in a vertically arranged layer of spongy tubes with openings that form a layer of small yellowish pores on the underside of the cap.
Boletus variipes is a species of mycorrhizal bolete fungus in the family Boletaceae, native to North America. It was originally described by American mycologist Charles Horton Peck in 1888.
Boletus rubriceps is a species of bolete fungus in the family Boletaceae. Although it was officially described as new to science in 2014, the bolete had previously been reported as either Boletus edulis or B. pinophilus. Molecular analysis showed that it was sufficiently different from other morphologically similar Boletus species to warrant designation as a distinct species. It is found in the southwestern United States and southern Rocky Mountains, where it associates with spruce, pine, and sometimes fir. The fruit bodies are edible and highly sought after; they are often sold in farmer's markets of Arizona, New Mexico, and Colorado, and are used in some restaurants. The specific epithet refers to the reddish color of the caps. Common names given to the bolete include "Ruby Porcini", "Rocky Mountain red-capped king bolete” or “Rocky Mountain red".
Imleria badia, commonly known as the bay bolete, is an edible, pored mushroom found in Eurasia and North America, where it grows in coniferous or mixed woods on the ground or on decaying tree stumps, sometimes in prolific numbers. Both the common and scientific names refer to the bay- or chestnut-coloured cap, which is almost spherical in young specimens before broadening and flattening out to a diameter up to 15 cm (6 in). On the cap underside are small yellowish pores that turn dull blue-grey when bruised. The smooth, cylindrical stipe, measuring 4–9 cm long by 1–2 cm thick, is coloured like the cap, but paler. Some varieties have been described from eastern North America, differing from the main type in both macroscopic and microscopic morphology.
↑ Sowerby J. (1809). Coloured Figures of English Fungi. Vol.4. London: J. Davis. p.199. This entire work is available in Commons here, but the reference is to plate 419 with textual description on page 697. Sowerby described the same modern species as B. edulis on plate 111 (description on page 57).
↑ Šutara J. (1985). "Leccinum and the question of superfluous names (Fungi: Boletaceae)". Taxon. 34 (4): 678–86. doi:10.2307/1222214. JSTOR1222214.
↑ Singer R. (1986). The Agaricales in Modern Taxonomy (4th rev.ed.). Koenigstein, Germany: Koeltz Scientific Books. p.779. ISBN3-87429-254-1.
↑ Smith AH, Thiers HD (1971). The Boletes of Michigan. Ann Arbor, Michigan: University of Michigan Press. p.221. Retrieved 2010-12-02.
↑ Binder M, Besl H, Bresinsky A (1997). "Agaricales oder Boletales? Molekularbiologische Befunde zur Zuordnung einiger umstrittener Taxa". Zeitschrift für Mykologie. 63: 189–196.
↑ Peter Howell, A Commentary on Book One of the Epigrams of Martial, The Athlone Press, 1980 p.152-3. Howell doubts the identification, and mentions the view advanced by Augusta A. Imholtz Jr., 'Fungi and piace- names, thè origin of boletus,' in AJP Vol.98, 1977 pp.71f., that the Latin word may derive from the Spanish town Boletum, modern-day Boltaña, south of the Pyrenees, which is still famous for its mushrooms.
↑ Pliny, Natural History, Bk. 16, 11, 31: "Such is the multiplicity of products in addition to the acorn that are borne by hard-oaks; but they also produce edible fungi (boletos) and hog mushrooms (suillos)." Pliny, Natural History, 10 vols., tr. H. Rackham, Harvard University Press/Heinemann, (1945) 1968, vol. 4, pp. 408–409.
↑ Neapolitansillo, and Calabriansillu/siddu. See Glauco Sanga, Gherardo Ortalli, Nature knowledge: ethnoscience, cognition, and utility, Berghahn Books, 2003 p. 78.
↑ Jarvis MC, Miller AM, Sheahan J, Ploetz K, Ploetz J, Watson RR, Ruiz MP, Villapan CA, Alvarado JG, Ramirez AL, Orr B (2004). "Edible wild mushrooms of the Cofre de Perote region, Veracruz, Mexico: An ethnomycological study of common names and uses". Economic Botany. 58 (Suppl. S): S111–S115. doi:10.1663/0013-0001(2004)58[S111:EWMOTC]2.0.CO;2. S2CID27729532.
↑ Spoerke DG, Rumack BH (1994). Handbook of Mushroom Poisoning: Diagnosis and Treatment. Boca Raton, Florida: CRC Press. p.11. ISBN0-8493-0194-7.
↑ Stensaas M, Sonstegard J (2004). Canoe Country Flora: Plants and Trees of the North Woods and Boundary Waters. Minneapolis, Minnesota: University of Minnesota Press. p.189. ISBN1-57025-121-5.
↑ Alexopoulos CJ, Mims CW, Blackwell M (1996). Introductory Mycology. New York City: John Wiley and Sons. p.495. ISBN0-471-52229-5.
↑ Vizzini A, Mello A, Ghignone S, Sechi C, Ruiu P, Bonfante P (2008). "Boletus edulis complex: from phylogenetic relationships to specific primers". Pagine di Micologia (30): 49–52. ISSN1122-8911.
↑ Mello A, Ghignone S, Vizzini A, Sechi C, Ruiu P, Bonfante P (2006). "ITS primers for the identification of marketable boletes". Journal of Biotechnology. 121 (3): 318–29. doi:10.1016/j.jbiotec.2005.08.022. PMID16213623.
↑ Miller HR, Miller OK (2006). North American Mushrooms: a Field Guide to Edible and Inedible Fungi. Guilford, Conn: Falcon Guide. p.392. ISBN0-7627-3109-5.
↑ Adhikary RK, Baruah P, Kalita P, Bordoloi D (1999). "Edible mushrooms growing in forests of Arunachal Pradesh". Advances in Horticulture and Forestry. 6: 119–23.
↑ Orlovich D, Stringer A, Yun W, Hall I, Prime G, Danell E, Weden C, Bulman S (2004). "Boletus edulis Bull. Ex Fries in New Zealand". Australasian Mycological Society Newsletter. 1 (1): 6.
↑ Eicker A. (1990). "Commercial mushroom production in South Africa". Bulletin (418). Pretoria: Department of Agricultural Development.
↑ Marais LJ, Kotzé JM (1977). "Notes on ectotrophic mycorrhizae of Pinus patula in South Africa". South African Forestry Journal. 100: 61–71. doi:10.1080/00382167.1977.9629436.
↑ Nilson S, Persson O (1977). Fungi of Northern Europe 1: Larger Fungi (Excluding Gill-Fungi). Harmondsworth, England: Penguin. p.100. ISBN0-14-063005-8.
↑ Salerni E, Perini C (2004). "Experimental study for increasing productivity of Boletus edulis s.l. in Italy". Forest Ecology and Management. 201 (2–3): 161–70. doi:10.1016/j.foreco.2004.06.027.
↑ Baar J, Ter Braak CJ (1996). "Ectomycorrhizal sporocarp occurrence as affected by manipulation of litter and humus layers in Scots pine stands of different age". Applied Soil Ecology. 4 (1): 61–73. doi:10.1016/0929-1393(96)00097-2.
↑ Baar J, de Vries FW (1995). "Effects of manipulation of litter and humus layer on ectomycorrhizal colonization potential in Scots pine stands of different age". Mycorrhiza. 5 (4): 267–72. doi:10.1007/BF00204960. S2CID32618842.
↑ Kasparavicius, J. (2001). "Influence of climatic conditions on the growth of fruit bodies of Boletus edulis". Botanica Lithuanica. 7 (1): 73–78. ISSN1392-1665.
↑ Martín-Pinto P, Vaquerizo H, Peñalver F, Olaizola J, Oria-de-Rueda J (2006). "Early effects of a wildfire on the diversity and production of fungal communities in Mediterranean vegetation types dominated by Cistus ladanifer and Pinus pinaster in Spain". Forest Ecology and Management. 225 (1–3): 296–305. doi:10.1016/j.foreco.2006.01.006.
↑ Quan L, Lei ZP (2000). "A study on effect of ectomycorrhizae on promoting Castanea mollissima resistance to drought and its mechanism". Forest Research (in Chinese). 13 (3): 249–56. ISSN1001-1498.
↑ Fu SC, Tan Q, Chen MJ, Shang XD, Cai LY, Zhang MY (2009). "Mycorrhizal synthesis involving Boletus edulis and Pinus massoniana". Acta Edulis Fungi. 16 (1): 31–41. ISSN1005-9873.
↑ Gross E, Thomazini-Casagrande LI, Caetano FH (1998). "A scanning electron microscopy study of ectomycorrhizae on Pinus patula Schiede and Deppe". Naturalia (Rio Claro). 23 (1): 93–101. ISSN0101-1944.
↑ Ceruti A, Tozzi M, Reitano G (1987–88). "Micorrize di sintesi tra Boletus edulis, Pinus sylvestris e Picea excelsa" [Mycorrhizal synthesis between Boletus edulis, Pinus sylvestris and Picea excelsa]. Allionia (Turin) (in Italian). 28: 117–24. ISSN0065-6429.
↑ Gobl F. (1977). "Mycorrhiza in Austrian Douglas fir stands". Centralblatt für das Gesamte Forstwesen (in German). 94 (4): 185–94. ISSN0379-5292.
↑ Froidevaux L, Amiet R (1975). "Ecto mycorrhizae endo mycorrhizae of Pinus mugo plus Boletus edulis ssp edulis and Pinus cembra plus Suillus variegatus formed in pure culture". European Journal of Forest Pathology. 5 (1): 57–61. doi:10.1111/j.1439-0329.1975.tb00935.x. ISSN0300-1237.
↑ Vozzo JA, Hackskaylo E (1961). "Mycorrhizal fungi on Pinus virginiana". Mycologia. 53 (5): 538–39. doi:10.2307/3756310. JSTOR3756310.
1 2 Agueda B, Parlade J, Fernandez-Toiran LM, Cisneros O, de Miguel AM, Modrego MP, Martinez-Pena F, Pera J (2008). "Mycorrhizal synthesis between Boletus edulis species complex and rockroses (Cistus sp.)". Mycorrhiza. 18 (8): 443–49. doi:10.1007/s00572-008-0192-3. PMID18695982. S2CID11233267.
↑ Águeda B, Parladé J, de Miguel AM, Martínez-Peña F (2006). "Characterization and identification of field ectomycorrhizae of Boletus edulis and Cistus ladanifer". Mycologia. 98 (1): 23–30. doi:10.3852/mycologia.98.1.23. hdl:10171/18758. PMID16800301.
↑ Peintner U, Iotti M, Klotz P, Bonuso E, Zambonelli A (2007). "Soil fungal communities in a Castanea sativa (chestnut) forest producing large quantities of Boletus edulis sensu lato (porcini): where is the mycelium of porcini?". Environmental Microbiology. 9 (4): 880–89. doi:10.1111/j.1462-2920.2006.01208.x. PMID17359260.
↑ Collin-Hansen C, Pedersen SA, Andersen RA, Steinnes E (2007). "First report of phytochelatins in a mushroom: induction of phytochelatins by metal exposure in Boletus edulis". Mycologia. 99 (2): 161–74. doi:10.3852/mycologia.99.2.161. PMID17682769.
↑ Lunghini D, Onofri S, Zucconi L (1984). "Some cases of intoxication probably caused by Sepedonium spp. infecting fruiting-bodies of some species of Boletus". Micologia Italiana (in Italian). 13 (1): 1/37–1/38. ISSN0390-0460.
↑ Bruns TD. (1984). "Insect mycophagy in the Boletales: fungivore diversity and the mushroom habitat". In Wheeler Q, Blackwell M (eds.). Fungus-Insect Relationships: Perspectives in Ecology and Evolution. New York, NY: Columbia University Press. pp.91–129. ISBN978-0-231-05695-3.
↑ Huttinga H, Wichers HJ, Dieleman van Zaayen A (1975). "Filamentous and polyhedral virus-like particle in Boletus edulis". Netherlands Journal of Plant Pathology. 81 (3): 102–106. doi:10.1007/BF01999860. S2CID35794592.
↑ Rolfe RT, Rolfe EW (1974). The Romance of the Fungus World. New York: Dover. p.287. ISBN0-486-23105-4.
↑ Brothwell DR, Brothwell P (1998) [1969]. Food in Antiquity: a Survey of the Diet of Early Peoples. Baltimore, MD: The Johns Hopkins University Press. p.92. ISBN0-8018-5740-6.
↑ Morford M. (1977). "Juvenal's Fifth Satire". The American Journal of Philology. 98 (3): 219–45. doi:10.2307/293772. JSTOR293772.
1 2 Jaworska G, Bernaś E (2008). "The effect of preliminary processing and period of storage on the quality of frozen Boletus edulis (Bull: Fr.) mushrooms". Food Chemistry. 113 (4): 936–43. doi:10.1016/j.foodchem.2008.08.023.
↑ Collin-Hansen C, Yttri KE, Andersen RA, Berthelsen BO, Steinnes E (2002). "Mushrooms from two metal-contaminated areas in Norway: occurrence of metals and metallothionein-like proteins". Geochemistry: Exploration, Environment, Analysis. 2 (2): 121–30. Bibcode:2002GEEA....2..121C. doi:10.1144/1467-787302-015. S2CID129662148.
↑ Collin-Hansen C, Andersen RA, Steinnes E (2005). "Molecular defense systems are expressed in the king bolete (Boletus edulis) growing near metal smelters". Mycologia. 97 (5): 973–83. doi:10.3852/mycologia.97.5.973. PMID16596949.
↑ Collin-Hansen C, Andersen RA, Steinnes E (2005). "Damage to DNA and lipids in Boletus edulis exposed to heavy metals". Mycological Research. 109 (12): 1386–96. doi:10.1017/S0953756205004016. PMID16353638.
↑ Marzano FN, Bracchi PG, Pizzetti P (2001). "Radioactive and conventional pollutants accumulated by edible mushrooms (Boletus sp.) are useful indicators of species origin". Environmental Research. 85 (3): 260–64. Bibcode:2001ER.....85..260M. doi:10.1006/enrs.2001.4233. PMID11237515.
↑ Grodzinskaya AA, Berreck M, Haselwandter K, Wasser SP (2003). "Radiocesium contamination of wild-growing medicinal mushrooms in Ukraine". International Journal of Medicinal Mushrooms. 5 (1): 61–86. doi:10.1615/InterJMedicMush.v5.i1.90. ISSN1521-9437.
↑ Lamaison JL, Polese JM (2005). The Great Encyclopedia of Mushrooms. Koln, Germany: Könemann. p.28. ISBN3-8331-1239-5.
↑ Misharina TA, Muhutdinova SM, Zharikova GG, Terenina MB, Krikunova NI (2009). "The composition of volatile components of cepe (Boletus edulis) and oyster mushrooms (Pleurotus ostreatus)". Applied Biochemistry and Microbiology. 45 (2): 187–93. doi:10.1134/S0003683809020124. PMID19382709. S2CID21525680.
↑ Sitta N, Floriani M (2008). "Nationalization and globalization trends in the wild mushroom commerce of Italy with emphasis on porcini (Boletus edulis and allied species)". Economic Botany. 62 (3): 307–22. doi:10.1007/s12231-008-9037-4. S2CID44274570.
↑ Veselkov IM. (1975). "Artificial propagation of Boletus edulis in forests". Растительньіе Ресурсы России. 11: 574–78.
↑ Ceruti A, Tozzi M, Reitano G (1988). "Micorize di sintesi tra Boletus edulis, Pinus sylvestris e Picea excelsa". Allionia (Turin) (in Italian). 28: 117–24.
↑ Fitter AH, Garbaye J (1994). "Interaction between mycorrhizal fungi and other organisms". In Robson AD, Abbott LK, Malajczuk N (eds.). Management of Mycorrhizas in Agriculture, Horticulture and Forestry. Dordrecht, Netherlands: Kluwer Academic Publishers. ISBN978-0-7923-2700-4.
↑ National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington (DC): National Academies Press (US). ISBN978-0-309-48834-1. PMID30844154.{{cite book}}: CS1 maint: multiple names: authors list (link)
↑ Ouzouni PK, Riganakos KA (2006). "Nutritional value and metal content profile of Greek wild edible fungi". Acta Alimentaria. 36 (1): 99–110. doi:10.1556/AAlim.36.2007.1.11.
↑ Crisan EV, Sands A (1978). "Nutritional value". In Chang ST, Hayes WA (eds.). The Biology and Cultivation of Edible Mushrooms. New York: Academic Press. pp.727–93. ISBN978-0-12-168050-3.
1 2 Kalač P. (2009). "Chemical composition and nutritional value of European species of wild growing mushrooms: a review". Food Chemistry. 113 (1): 9–16. doi:10.1016/j.foodchem.2008.07.077.
↑ Pedneault K, Angers P, Gosselin A, Tweddell RJ (2006). "Fatty acid composition of lipids from mushrooms belonging to the family Boletaceae". Mycological Research. 110 (Pt 10): 1179–83. doi:10.1016/j.mycres.2006.05.006. PMID16959482.
↑ Ribeiro B, Andrade PB, Silva BM, Baptista P, Seabra RM, Valento P (2008). "Comparative study on free amino acid composition of wild edible mushroom species". Journal of Agricultural and Food Chemistry. 56 (22): 10973–79. doi:10.1021/jf802076p. PMID18942845.
↑ Tsai SY, Tsai HL, Mau JL (2008). "Non-volatile taste components of Agaricus blazei, Agrocybe cylindracea and Boletus edulis". Food Chemistry. 107 (3): 977–83. doi:10.1016/j.foodchem.2007.07.080.
↑ Su, Jiuyan; Zhang, Ji; Li, Jieqing; Li, Tao; Liu, Honggao; Wang, Yuanzhong (6 April 2018). "Determination of mineral contents of wild Boletus edulis mushroom and its edible safety assessment". Journal of Environmental Science and Health, Part B. 53 (7): 454–463. doi:10.1080/03601234.2018.1455361. ISSN0360-1234. PMID29624491. S2CID4665228.
↑ Mutanen M. (1986). "Bioavailability of selenium in mushrooms". International Journal for Vitamin and Nutrition Research. 56 (3): 297–301. PMID3781756.
↑ Mattila P, Lampi AM, Ronkainen R, Toivo J, Piironen V (2002). "Sterol and vitamin D2 contents in some wild and cultivated mushrooms". Food Chemistry. 76 (3): 293–98. doi:10.1016/S0308-8146(01)00275-8.
↑ Ey J, Schömig E, Taubert D (2007). "Dietary sources and antioxidant effects of ergothioneine". Journal of Agricultural and Food Chemistry. 55 (16): 6466–74. doi:10.1021/jf071328f. PMID17616140.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
