The word truffle derives from the Latin term tuber, meaning "swelling" or "lump", which became tufer and gave rise to the various European terms: French truffe, Spanish trufa, German Trüffel, Dutch truffel, Croatian tartuf, Italian Tartufo, Portuguese trufa or tubera.
Truffle is the generic name to a species belonging to the genus Tuber within the larger fungi group. The truffle’s sporocarp (also known as fruiting body or fruit body) grows underground thanks to a symbiotic relationship (mycorrhiza) with the roots of several tree species including beech, poplar, oak, birch, hornbeam, hazel, and pine. The truffle’s underground biological cycle is defined as hypogeous in contrast to the common mushroom defined as epigeous because it grows above ground.
Truffles do not release their spores at maturity as a reproductive method as it is the case with many types of mushrooms; instead, they produce strong aromas to attract consumers. These aromas are made up of complex mixtures of volatile organic compounds. These attract animals, including mammals and insects, which eat the truffles. Thus, the reproductive spores of the truffles pass though the gut of the animal before being deposited in a fertilized land often many kilometers from where the truffles were eaten. A number of the same aromas that attract animals make commercial edible truffles attractive to us as well.
All truffles tend to be roughly spherical, although their shape is often moulded by stones in the soil where they are growing. When mature, truffles tend to be firm or even hard to the touch, dense, and almost woody.
The typical morphological aspect of a truffle is made of an outer protective layer (peridium) and an inner mass (gleba). The peridium can be smooth or sculptured. Its color varies from light to dark. The color of the gleba instead varies from white to black and from pink to brown. The gleba is crisscrossed with countless veins delimiting alveoli containing asci (reproductive spore-bearing cells).
The entire mass of the truffle is composed by 85% water, 5% proteins, 2% ashes, 2% fat, 2% carbohydrates, 4% soluble fiber. Hence, given the large presence of water, the truffle has limited nutritional value. Its allure resides mostly in its capacity to give pleasure to the user.