Biological aspects and morphology of the Truffle
The truffle is an underground fungus that belongs to the class Ascomycetes of the genus tuber.
In fact, the truffle is the prized fruit(carpophore) of the underground(hypogean) mushroom to which it belongs.
These fungi lack chlorophyll and therefore are unable to assimilate carbon from the atmosphere to synthesize organic matter on which to feed. For this reason, truffles can only live in symbiosis with tree and shrub plants through a dense network of structures called mycorrhizae. Mycorrhizae consist of very many filaments called hyphae, which wrap around the rootlets of the host plant, without damaging them, to extract organic nutrients from them.
In this way, the truffle can utilize the carbohydrates obtained by the plant through photosynthesis, but the host plant also obtains numerous benefits including an increase in absorbent surface area due to the expansion of hyphae that form an extensive mantle around the roots. In addition, the truffle reduces the attack of pathogens on the roots and its mycelium has ten times the water absorption capacity of the plant's root system.
Truffle truffle plants.
The tree and shrub species that habitually live associated with truffles number a few dozen and belong to the Gymnosperms and Angiosperms. Each truffle species, although it can mycorrhize with a good number of symbiont plants, has special affinities with some of them. Alongside the symbiont plants there are also the comary or companion plants, which although they do not carry the mycorrhizae of truffles facilitate their formation either by shading the soil and thus ensuring moisture, or by providing nourishment through the decomposition of leaves and rootlets.
Umbria's wild flora is rich in truffle plants and the humid climate of its forests, the presence of rivers and streams, favor mycorrhization ensuring a rich production of high quality truffles, from the black truffle of Norcia and Spoleto to the white truffle of the upper Tiber Valley, Gubbio and Orvieto.
Among the most common symbiont trees and shrubs in Umbria we can mention:
- for Broadleaves (Angiosperms)- Oak, Holm oak, Hornbeam, Chestnut, Hazel, Oak, Poplar;
- For the Shrubs (Gymnosperms) - Aleppo pine, Lodgepole pine, Black pine.
The Scent of Truffle
The truffle is one of nature's most harmonious products, and its fragrance is the most important characteristic. The fragrance is not comparable to any of the other mushrooms, it changes intensity depending on the species and the degree of ripeness. The aroma is as distinctive as it is impossible to describe. The fragrance, together with the flavor are the most valuable characteristics of truffles those that give them uniqueness and value.
Brillat-Savarin, considered the father of modern gastronomy and gastrosophy had this to say:
"The scent and flavor of truffles induce in the consumer a refined palate satisfaction that induces brio and pleasure."
From an organic point of view, scent is basic in conferring greater value to the truffle, but it is even more important from a naturalistic point of view. Scent has a fundamental function for the purpose of reproduction. The scent allows the truffle to be identified and attracts wild animals that feed on it (wild boars, porcupines, foxes, badgers, mice, hedgehogs, squirrels). The latter disperse the spores into the environment, which pass through their intestines unharmed, and in this way the truffle can continue to reproduce.
With this first article we wanted to begin our review on truffles, which from the next issue will focus on the different species, their qualities, harvesting techniques, properties and uses in cooking.