Black Diamond of the Earth

Among truffles, there are two broad categories — the black truffle (Tuber melanosporum) and the white truffle (Tuber magnatum) Truffles are highly sought after, and therefore they can be incredibly expensive. White truffles fetch jaw dropping prices in auctions! 

The indiscriminate capture of ornamental fish from the wild without adequate replenishment is a serious threat to the biodiversity of the state 

Land Treasure 

Truffles with the sobriquet ‘black gold’ or ‘black diamond of the earth’ is the subterranean, edible, nearly globose, fruiting body of the Ascomycete fungus of the genus Tuber, grown symbiotically on specific tree roots. Truffles are highly priced for its culinary value so much so that it is called as ‘the diamond of the kitchen’. Edible truffles are held in high esteem in French, Croatian, Georgian, Bulgarian, Greek, Italian, Middle Eastern, and Spanish cuisine, as well as in international haute cuisine. 

Indian Perspective 

In India, truffles are rather arcane. But as more and more Indians are travelling to western countries, it’s becoming familiar in the country and the demand is increasing. Recently ITC Grand Chola organised a truffles tour at Chennai. 

Morphometry 

Truffles can reach 12 cm (5 in) diameter and weigh around 500 g. However, some truffles may be significantly larger weighing more than one kg. In December 2014, a white truffle weighing 4.16 pounds or 1.89 kilograms was unearthed in the Umbrian region of Italy. Truffles are more or less globose in shape. 

Black, White and Other Truffles 

Among truffles, there are two broad categories — the black truffle (Tuber melanosporum) and the white truffle (Tuber magnatum). The black truffle (Périgord truffle or French black truffle)is generally smaller than its white counterpart, but is more common .Black truffles, also referred to as the ‘black diamond of the earth’, were originally found across Europe but now spread to many other countries. The white truffle (Truffle of the White Madonna in Italian) is found mainly in Italy and France .A slightly different variety of white truffle has also been found in the USA, Qatar and some other Middle East countries. However, the Italian white truffles are the best and most valuable one in the market. 

Taste 

There are lots of different ways to describe the flavor and odor of truffles, but generally it is described as slightly garlicky with a deep musky aroma. It’s very earthy and pungent. 

Host Trees 

Truffles grow at a depth of 5 cm (2.0 in) to 50 cm (20 in) as ectomycorrhizae, colonising on the roots of their host trees such as holm oaks, French oaks, hazel, beech, birch, pine, cherry and other deciduous trees. In the United States, they can sometimes be found growing with pecan trees too. However, in Qatar, the favoured host plant is the desert sunflower growing up to a height of one meter. Black truffles sometimes suppress the growth of plants around their symbiont, creating the impression of a burnt area around it. They do so by parasitizing the roots of other plants, which may lead to necrosis of the root bark and the death of the host plants.

Production 

France accounted for about 45% of the world production of black truffles followed by, Spain (35%) and Italy (20%). But now Australia, New Zealand and USA are also in the fray. Smaller amounts are produced in Slovenia, Serbia and Croatia. The European Union funded Rural Development Programme provides subsidy for truffle culture and has a visible effect in production since 2010-2011. Total production was 448MT during 2013-14 from Spain, France, Italy and European Union together while Australia produces around 600kg. 

Treasure Hunt 

Trained animals like pigs and dogs with strong olfactory prowess are used, though not exclusively, to locate and track down the subterranean pungent culinary delight and unearth them from the leaf litter and soil. Unfortunately as pigs devour the located treasure, now-a-days, dogs which are trained from very young age, are preferred for hunting the truffle. These animals locate the truffles attracted by the odour of some compounds the fungi emit. In Italy, the use of the pig to hunt truffles has been prohibited since 1985 because of damage caused by the animal to the truffle ecosystem during the digging that shackles the production rate. In Qatar, the entire family does the hunting without the help of any animals. 

Truffle Troubles 

War over truffles is very common in Albania’s (South Eastern Europe) forests by rival groups during the truffle season. The hunter dogs are poisoned and host trees are destroyed .Reckless hunters attack the forest land with pickaxes and sharp spades destroying the root system of the host trees and thereby killing the golden goose! 

Propagation 

Boars and the larvae of the truffle fly (Suillia tuberiperda), which eat the fruiting bodies, aid in the distribution of the species by excreting the indigestible spores. Cultured fungal mycelium or spores is used as the inoculums in truffle culture. 

Truffle Farming 

Though some amount of truffles are still collected from the wild sources, cultivated truffles form a major chunk of production now. Truffle culture or cultivation of truffles has its beginning in the 19th century but it got sidelined or neglected for most part of the 20th century. However, during the last 35 years, again scientific cultivation of truffles gained momentum. Black truffles are now cultivated in Australia, France, New Zealand, Chile, Sweden, United Kingdom, USA, and South Africa. Cultivation involves the planting and establishing of the host tree orchards and inoculation of the host rhizosphere with truffle mycelium. A critical phase of the cultivation is the quality control of the mycorrhizal plants. Before inoculating the truffle mycelia, other contaminating soil fungi in the rhizosphere of the host plants are to be controlled to ensure the establishment of the truffle mycelia and success of the plantation. Once the rhizosphere is cleared off the competing fungi, then the truffle mycelia culture is inoculated to the root zone of the host tree. Well drained argillaceous or calcareous soils with neutral or alkaline pH are ideal for truffle farming. 

Truffles don’t like the extremes of temperature, or extremes of moisture. It takes between 7 and 10 years for the truffles to develop their mycorrhizal network, and only after that the host-plants come into production of the fruiting bodies, the culinary delight. Total investment per hectare for an irrigated and fenced plantation (against wild boars) can cost up to €10,000(about Rs. 8 lakhs). Few big companies are now in to the business of truffle production.A Western Australian venture, The Truffle & Wine Company, had its first harvest in 2004, and in 2005 they dug up a 1 kg truffle. In 2008, an estimated 600 kilograms of truffles were produced at Manjimup, Western Australia. However, in 1999, the first Australian truffles were harvested in Tasmania from a eight year old plantation, while in June 2010, the Tasmanian growers harvested Australia’s largest truffle weighing 1.084 kilograms and was valued at about A$1,500 per kg.

Prior to this, Gisborne in New Zealand recorded the first harvest of truffles from the inoculated trees in the year 1993. New World Truffieres is a North American company engaged in transfer of technology of truffle production including myceila (spore) culture and inoculation as well as orchard raising and management to farmers in USA besides successfully producing the commodity since 2000 in orchards of oak and hazelnut. They also organize annual meet of the growers. Eighty percent of the truffles now produced in France come from specially planted truffle groves. The fruiting bodies develop from April to June, and are harvested during November to March. 

Truffle Trade 

Truffles are highly sought after, and therefore they can be incredibly expensive. White truffles fetch jaw dropping prices in auctions! The record price paid for a single white truffle unearthed from Pisa, Italy was $330,000 in 2007, auctioned simultaneously at Macau, Hong Kong and Florence. As of December 2009 the price of white truffles was $14,203.50 per kg. However, in December 2014, a white truffle weighing 1.89 kilos in the Umbrian region of Italy and was auctioned in New York for $61,000 to a Taiwanese buyer! However, the record price paid for a single white truffle was set in December 2007, when Macau casino owner Stanley Ho paid a whopping $330,000 (£165,000) for a specimen weighing 1.5 kilograms !.

With a price of about 1,000 to 2,000 euros per kilogram, black truffles are the second most expensive truffles after white truffles, and one of the most sought after edible mushrooms in the world. The largest truffle market in France (and probably also in the world) is at Richerenches in Vaucluse. These markets are busiest in the month of January, when the black truffles have their highest perfume. A cheap inferior quality Chinese truffles are found creating havoc in truffle trade. 

Culinary uses 

Because of their high price and pungent aroma, truffles are used sparingly. Fresh black truffles or preserved in light brine, are used to refine the taste of meat, fish, soups and risotto. Unlike white truffles, the aroma of black truffles does not diminish when heated, but becomes more intense. In Spain, where black truffles have a strong prominence, one truffle dish is known as blanched eggs, or huevos escaldados in Spanish .The flavour of black truffles is far less pungent and more refined than that of white truffles. Their strong flavour is often described as syrupy sweet. Black truffles also are used for producing value added salt(truffle salt) and honey(truffle honey).

White truffles are generally served raw and shaved over steaming buttered pasta, salads, or fried eggs. White or black paper-thin truffle slices may be inserted into meats, under the skins of roasted fowl, in foie gras preparations, in pâtés, or in stuffings. Some specialty cheeses contain truffles as well. While in the past ,chefs used to peel truffles, in modern times, most restaurants brush the truffle carefully and shave it or dice it with the skin on so as to make the most of this valuable ingredient. A few restaurants in Switzerland still stamp out circular discs of truffle flesh and use the skins for sauces. Adulteration or substitution of genuine truffles with inferior quality Chinese truffles is posing a problem to the trade and foodies. 

Author
Dr. B Sasikumar Principal Scientist and Head (Rtd.)
Crop Improvement and Biotech.Dvn.,
ICAR-Indian Inst.of Spices Research, Kozhikode
Email: sasikumarsooranadu@gmail.com