Product Code Database
A truffle is the fruiting body of a subterranean ascomycete fungus, one of the species of the genus Tuber. More than one hundred other genera of fungi are classified as truffles including Geopora, Peziza, Choiromyces, and Leucangium. These genera belong to the class Pezizomycetes and the Pezizales order. Several truffle-like basidiomycetes are excluded from Pezizales, including Rhizopogon and Glomus.
Truffles are fungi, so they are found in close association with tree roots. Spore dispersal is accomplished through , animals that eat fungi. These fungi have ecological roles in nutrient cycling and drought tolerance.
Some truffle species are prized as food. English translation Edible truffles are used in Italian cuisine, French cuisine and other national . Truffles are Fungiculture and harvested from natural environments.
In the U.S. Pacific Northwest, several species of truffle are harvested both recreationally and commercially, most notably, the Leucangium carthusianum, Oregon black truffle; Tuber gibbosum, Oregon spring white truffle; and Tuber oregonense, Oregon winter white truffle. Kalapuya brunnea, the Oregon brown truffle, has also been commercially harvested and is of culinary note. The Oregon white truffle is increasingly harvested due to its high quality and also exported to other countries. Oregon celebrates its traditional truffle harvesting with a 'truffle festival', combined with culinary shows and wine tastings. "Oregon Native Truffles: A primer for commercial production on small forestlands in the Pacific Northwest". Know Your Forest. Accessed 8 October 2023.
The pecan truffle ( Tuber lyonii) syn. texense is found in the Southern United States, usually associated with pecan trees. Chefs who have experimented with them agree "they are very good and have potential as a food commodity". Although pecan farmers used to find them along with pecans and discard them, considering them a nuisance, they sell for about $160 a pound and have been used in some gourmet restaurants.
Geopora spp. are important ectomycorrhizal partners of trees in woodlands and forests throughout the world. Pinus edulis, a widespread pine species of the Southwest US, is dependent on Geopora for nutrient and water acquisition in arid environments. Like other truffle fungi, Geopora produces subterranean sporocarps as a means of sexual reproduction. Geopora cooperi, also known as pine truffle or fuzzy truffle, is an edible species of this genus.
Rhizopogon spp. are ectomycorrhizal members of the Basidiomycota and the order Boletales, a group of fungi that typically form mushrooms. Like their ascomycete counterparts, these fungi can create truffle-like fruiting bodies. Rhizopogon spp. are ecologically important in coniferous forests where they associate with various pines, firs, and Douglas fir. In addition to their ecological importance, these fungi hold economic value, as well. Rhizopogon spp. are commonly used to inoculate coniferous seedlings in nurseries and during reforestation.
Hysterangium spp. are ectomycorrhizal members of the Basidiomycota and the order Hysterangiales that form sporocarps similar to true truffles. These fungi form mycelial mats of vegetative hyphae that may cover 25–40% of the forest floor in Douglas fir forests, thereby contributing to a significant portion of the biomass present in soils. Like other ectomycorrhizal fungi, Hysterangium spp. play a role in nutrient exchange in the nitrogen cycle by accessing nitrogen unavailable to host plants and acting as nitrogen sinks in forests.
Glomus spp. are arbuscular mycorrhizae of the phylum Glomeromycota within the order Glomerales. Members of this genus have low host specificity, associating with a variety of plants including hardwoods, forbs, shrubs, and grasses. These fungi commonly occur throughout the Northern Hemisphere.
Members of the genus Elaphomyces are commonly mistaken for truffles.
The oldest ectomycorrhizal fossils are from the Eocene about 50 million years ago. The specimens are preserved permineralized in-situ in the Eocene Okanagan Highlands Princeton chert site. This indicates that the soft bodies of ectomycorrhizal fungi do not easily fossilize. Molecular clockwork has suggested the evolution of ectomycorrhizal fungi occurred approximately 130 million years ago.
The evolution of subterranean fruiting bodies has occurred numerous times within the Ascomycota, Basidiomycota, and Glomeromycota. For example, the genera Rhizopogon and Hysterangium of Basidiomycota both form subterranean fruiting bodies and play similar ecological roles as truffle forming ascomycetes. The ancestors of the Ascomycota genera Geopora, Tuber, and Leucangium originated in Laurasia during the Paleozoic era.
Phylogenetic evidence suggests that most subterranean fruiting bodies evolved from above-ground mushrooms. Over time mushroom stipes and caps were reduced, and caps began to enclose reproductive tissue. The dispersal of sexual spores then shifted from wind and rain to utilising animals.
The phylogeny and biogeography of the genus Tuber was investigated in 2008 using internal transcribed spacers (ITS) of nuclear DNA and revealed five major (Aestivum, Excavatum, Rufum, Melanosporum and Puberulum); this was later improved and expanded in 2010 to nine major clades using 28S (LSU) rRNA of mitochondrial DNA. The Magnatum and Macrosporum clades were distinguished as distinct from the Aestivum clade. The Gibbosum clade was resolved as distinct from all other clades, and the Spinoreticulatum clade was separated from the Rufum clade.
The truffle habit has evolved independently among several basidiomycete genera. Phylogenetic analysis has revealed that basidiomycete subterranean fruiting bodies, like their ascomycete counterparts, evolved from above ground mushrooms. For example, Rhizopogon species likely arose from an ancestor shared with Suillus, a mushroom-forming genus. Studies have suggested that selection for subterranean fruiting bodies among ascomycetes and basidiomycetes occurred in water-limited environments.
Tuber species prefer argillaceous or calcareous soils that are well drained and neutral or alkaline. Tuber truffles fruit throughout the year, depending on the species, and can be found buried between the Plant litter and the soil. Most fungal biomass is found in the humus and litter layers of soil.
Most truffle fungi produce both asexual spores (mitospores or conidia) and sexual spores (meiospores or /). Conidia can be produced more readily and with less energy than ascospores and can disperse during disturbance events. Production of ascospores is energy intensive because the fungus must allocate resources to the production of large sporocarps. Ascospores are borne within sac-like structures called asci, which are contained within the sporocarp.
Because truffle fungi produce their sexual fruiting bodies underground, spores cannot be spread by wind and water. Therefore, nearly all truffles depend on Fungivore animal vectors for spore dispersal. This is analogous to the dispersal of seeds in fruit of angiosperms. When the ascospores are fully developed, the truffle exudes volatile compounds that attract animal vectors. For successful dispersal, these spores must survive passage through the digestive tracts of animals. Ascospores have thick walls composed of chitin to help them endure the environment of animal guts.
Animal vectors include birds, deer, and rodents such as , , and . Many species of trees, such as Quercus garryana, are dependent on the dispersal of sporocarps to inoculate isolated individuals. For example, the acorns of Q. garryana may be carried to new territory that lacks the necessary mycorrhizal fungi for establishment.
Some mycophagous animals depend on truffles as their dominant food source. Flying squirrels, Glaucomys sabrinus, of North America play a three-way symbiosis with truffles and their associated plants. G. sabrinus is particularly adapted to finding truffles using its refined sense of smell, visual clues, and long-term memory of prosperous populations of truffles. This intimacy between animals and truffles indirectly influences the success of mycorrhizal plant species.
After ascospores are dispersed, they remain dormant until germination is initiated by exudates excreted from host plant roots. Following germination, hyphae form and seek out the roots of host plants. Arriving at roots, hyphae begin to form a mantle or sheath on the outer surface of root tips. Hyphae then enter the root cortex intercellularly to form the Hartig net for nutrient exchange. Hyphae can spread to other root tips colonising the entire root system of the host. Over time, the truffle fungus accumulates sufficient resources to form fruiting bodies. Rate of growth is correlated with increasing photosynthetic rates in the spring as trees leaf out.
Truffles have been suggested to co-locate with the orchid species Epipactis helleborine and Cephalanthera damasonium, though this is not always the case.
Mycelial mats can also help maintain the structure of soils by holding organic matter in place and preventing erosion. Often, these networks of mycelium provide support for smaller organisms in the soil, such as bacteria and microscopic . Bacteria feed on the exudates released by mycelium and colonise the soil surrounding them. (2025). 9783540291824, Springer. ISBN 9783540291824 Microscopic arthropods such as mites feed directly on mycelium and release valuable nutrients for the uptake of other organisms.Moldenke, A.R., 1999. Soil-dwelling arthropods: their diversity and functional roles. United States Department of Agriculture Forest Service General Technical Report PNW. 33-44. Thus, truffle fungi and other ectomycorrhizal fungi facilitate a complex system of nutrient exchange between plants, animals, and microbes.
As global temperatures rise, so does the occurrence of severe droughts, detrimentally affecting the survival of aridland plants. This variability in climate has increased the mortality of P. edulis. Therefore, the availability of compatible mycorrhizal inoculum can greatly affect the successful establishment of P. edulis seedlings. Associated ectomycorrhizal fungi will likely play a significant role in the survival of P. edulis with continuing global climate change.
| +Comparison of truffle dog and hog !Truffle dog !Truffle hog | |
| Keen sense of smell | Keen sense of smell |
| Must be trained | Innate ability to sniff out truffles |
| Easier to control | Tendency to eat truffles once found |
In Italy, the use of pigs to hunt truffles has been prohibited since 1985 because of damage caused by animals to truffle mycelia during the digging that dropped the production rate of the area for some years. An alternative to truffle pigs are dogs. Dogs offer an advantage because they do not have a strong desire to eat truffles, so they can be trained to locate sporocarps without digging them up. Pigs attempt to dig up truffles.
Fly species of the genus Suillia can also detect the volatile compounds associated with subterranean fruiting bodies. These flies lay their eggs above truffles to provide food for their young. At ground level, Suilla flies can be seen flying above truffles.
The most learned men have sought to ascertain the secret and fancied they discovered the seed. Their promises, however, were vain, and no planting was ever followed by a harvest. This perhaps is all right, for as one of the great values of truffles is their dearness, perhaps they would be less highly esteemed if they were cheaper.
Truffles can be cultivated. As early as 1808, attempts to cultivate truffles, known in French as trufficulture, were successful. People had long observed that truffles were growing among the roots of certain trees, and in 1808, Joseph Talon, from Apt (département of Vaucluse) in southern France, had the idea of transplanting some seedlings that he had collected at the foot of oak trees known to host truffles in their root system.
For discovering how to cultivate truffles, some sources now give priority to Pierre II Mauléon (1744–1831) of Loudun (in western France), who began to cultivate truffles around 1790. Mauléon saw an "obvious symbiosis" between the oak tree, the rocky soil, and the truffle and attempted to reproduce such an environment by taking acorns from trees known to have produced truffles and sowing them in chalky soil.See: Thérèse Dereix de Laplane (2010) "Des truffes sauvages aux truffes cultivées en Loudunais" (From wild truffles to cultivated truffles in the area of Loudun), Mémoires de l'Académie des Sciences, Arts et Belles-Lettres de Touraine, 23 : 215–241. Available on-line at: Academy of Touraine From pp. 224–225: "le paysan, a alors l'idée, vers 1790 — puisqu'il y a symbiose évidente entre le chêne, les galluches et la truffe — de provoquer la formation de truffières, en reproduisant leur environnement naturel par des semis de glands dans ses "terres galluches". Avec "les glands venus sur les chênes donnant les truffes, des semis furent faits dans les terrains calcaires voisins"" (the farmer viz, then had the idea, around 1790 — because there is an obvious symbiosis between the oak tree, the rocky soil, and truffles — of inducing the formation of truffle patches, by reproducing their natural environment by sowing acorns in his rocky soils. With "the acorns that came from the oak trees producing truffles, sowings were made in the neighbouring chalky plots") "Culture de la truffe à Loudun et à Richelieu," Annales de la Société d'Agriculture Sciences, Arts, et Belles-lettres du Départment d'Indre-et-Loire, 10th series, 48 : 300–302 (1869); see p. 300. His experiment was successful, with truffles found in the soil around the newly grown oak trees years later. In 1847, Auguste Rousseau of Carpentras (in Vaucluse) planted of oak trees (again from acorns found on the soil around truffle-producing oak trees), and he subsequently obtained large harvests of truffles. He received a prize at the 1855 World's Fair in Paris.Rousseau, "Truffes obtenues par la culture de chênes verts" (Truffles obtained by the cultivation of green oaks) in: Exposition universelle de 1855 : Rapports du jury mixte international, volume 1 (Paris, France: Imprimerie Impériale, 1856), pp. 173-174.
Others imitated these successful attempts in France and Italy. In the late 19th century, an epidemic of phylloxera destroyed many of the vineyards in southern France. Another epidemic killed most of the there, too, making the fields of mulberry trees useless. Trufficulture became an important source of income for those affected. The calcareous and exposed vineyard soils were well-suited to the cultivation of truffles. By 1890, truffières (truffle plantations) covered 750 km2 of land in France, and 2,000 tonnes of truffles were produced in that year.
From the 19th century to the present, truffle production fell by 97–99% to 20–50 tonnes annually. Reasons given for this decline include the Industrial Revolution, the subsequent rural flight and the multiple European wars of the 20th century, which reduced the rural population. For example, World War I resulted in the mobilisation of 65% of the agricultural workers from the region of Lot alone. Knowledge of truffle cultivation, the soil and the seasons was lost along with the people. Another consequence was no more grazing sheep or shepherds who pruned trees for feed and fuelwood, so former truffle plantations turned into closed forests that no longer produced truffles. Truffles were once sold at weekly markets (bi-weekly in the case of a market in Martel, Lot) and in quantities of two to six tonnes in good weeks, but only Lalbenque and Limogne today have weekly truffle markets. Prices have increased so that truffles, once seen as a food of the middle class, have become a luxury.
The situation changed in the late 1960s and early 1970s, with researchers in France and Italy establishing mycorrhizas with truffle spores. Beginning from the 1980s, truffle plantations are compensating for some of the decline in wild truffles, and exist in various countries including France, Italy, Spain and Australia. About 80% of the truffles now produced in France come from specially planted truffle groves. Investments in cultivated plantations are underway in many parts of the world using controlled irrigation for regular and resilient production.
A critical phase of the cultivation is the quality control of the mycorrhizal plants. Between 7 and 10 years are needed for the truffles to develop their mycorrhizal network, and only after that do the host plants come into production. Complete soil analysis to avoid contamination by other dominant fungi and very strict control of the formation of mycorrhizae are necessary to ensure the success of a plantation. Total investment per hectare for an irrigated and barrier-sealed plantation (against wild boars) can cost up to €10,000. Considering the level of initial investment and the maturity delay, farmers who have not taken care of both soil conditions and seedling conditions are at high risk of failure.
New Zealand's first burgundy truffle was found in July 2012 at a Waipara truffle farm. It weighed 330 g and was found by the farm owner's beagle.
In 1999, the first Australian truffles were harvested in Tasmania, the result of eight years of work. Trees were Inoculation with the truffle fungus to create a local truffle industry. Their success and the value of the resulting truffles has encouraged a small industry to develop.
Truffle production has expanded into the colder regions of Victoria, New South Wales and Western Australia. In 2014, over of truffles were harvested by Truffle Hill, Manjimup, Western Australia.
In June 2014, a grower harvested Australia's largest truffle from their property at Robertson, in the Southern Highlands of New South Wales. It was a French black périgord fungus weighing in at and was valued at over $2,000 per kilogram.
Their chemical compounds infuse well with fats such as butter, cream, cheeses, avocados, and coconut cream.
As the volatile aromas dissipate quicker when heated, truffles are generally served raw and shaved over warm, simple foods which highlight their flavour, such as buttered pasta or . Thin truffle slices may be inserted into , under the skins of roasted fowl, in foie gras preparations, in pâtés, or in . Some speciality contain truffles, as well. Truffles are also used for producing truffle salt and truffle honey.
While chefs once peeled truffles, in modern times, most restaurants brush the truffle carefully and shave it or dice it with the skin on to make the most of the valuable ingredient. Some restaurants stamp out circular discs of truffle flesh and use the skins for sauces.
The scientific name is included on the ingredient list of truffle oils infused with natural truffles.
Ancient Rome and Thracia in the Ancient Rome period identified three kinds of truffles: Tuber melanosporum, T. magnificus, and Tuber magnatum. The Romans instead used a variety of fungus called Terfeziaceae, also sometimes called a "desert truffle". Terfez used in Rome came from Lesbos, Carthage, and especially Libya, where the coastal climate was less dry in ancient times. Their substance is pale, tinged with rose. Unlike truffles, terfez have little inherent flavour. The Romans used the terfez as a flavour carrier because the terfez tends to absorb surrounding flavours. Because Ancient Roman cuisine used many spices and flavourings, the terfez may have been appropriate in that context.
|
|
