Italian white truffle, the ABC

The prized white truffle (Tuber magnatum  Picco) is the most precious and celebrated species in Italian haute cuisine, as well as in French cuisine. The ABC follows.

Truffles in Europe and Italy, introduction

Truffles, as seen, are hypogeous fungi highly valued for their distinctive organoleptic properties, promising health benefits, as well as ecosystem services supporting host plants. (1)

The species of truffles recorded are about 60, of which 20 grow in Europe and are all present in Italy. However, only 7 species can be marketed in Italy (Italian law 752/1985 on the collection, preservation, and commercialization of truffles). (2)

The white truffle

Tuber magnatum  Picco  – the prized white truffle, also called ‘trifola bianca’ (or ‘Italian white truffle’, or ‘Alba truffle’) – is distinguished from other truffle species by the following characteristics:

• rounded ascocarp (see cover image),
• outer layer (peridium) smooth or ‘velvety’, color ranging from light yellowish brown to ochre yellow,
• internal structure (gleba) traversed by numerous fine and light veins, which at maturity reach a light hazelnut color tone.

The asci may present abnormal red spots (superficial, or inside the gleba) caused by microorganisms, fungi and/or bacteria inhabiting the ascus itself. (3) However, they do not alter the aromatic properties nor the commercial value of the white truffle.

Habitat natural

TheHabitat natural of the prized white truffle is characterized by:

• valley bottom soils, deep, with a balance of sand, silt and clay, as well as rich in carbonates and with a sub-alkaline reaction, (4)
• mutualistic symbiosis with trees such as oaks, hazels, willows, hornbeams, linden and poplars.

Italy is one of the main sites for the collection of the prized white truffle, which takes place especially in Piedmont, Tuscany, Marche, Emilia-Romagna and Umbria. (5) As well as in other countries of the Old Continent, from France and Switzerland towards Hungary, Romania and Bulgaria, up to the Balkans.

Cultivation, the role of mycorrhizae

The cultivation of some species of truffles (Tuber magnatum , T. aestivum, T. melanosporum) has been experimented with since the 1970s but has so far proved difficult. (6) The life cycle and development of the truffle are in fact linked to a complex ecosystem, influenced by many biotic and abiotic factors (e.g. nutritional status, interaction with the host plant, climate and microclimate, microbial biodiversity).

The mycorrhizae have moreover proven able to maintain over decades a natural truffle ground dedicated to the white truffle in Italy (Mombercelli, province of Asti, Piedmont), thanks to the extraordinary research and innovation of biologist Giusto Giovannetti of the Experimental Cultures Center (CCS) in Aosta (7,8). The INRAE institute in France has in turn demonstrated, in recent years, the possibility of cultivating prized white truffle precisely thanks to mycorrhizae. (9)

Aromas and preservation

The aromas – one of the main indicators of freshness, distinctive quality and value of the prized white truffle (10) – are influenced by various factors and are often described as sulfurous, or garlicky, due to the presence of volatile sulfur-containing substances. (11)

Preservation can severely compromise the aroma and organoleptic properties of  Tuber magnatum  Picco. Research into optimal preservation methods has therefore focused on freeze-drying, although more expensive, compared to freezing. (1).

Market and risks of food fraud

The international production The production of white truffle varies significantly over the years due to seasonality, cultivation difficulties and unpredictable yields. Its price can consequently fluctuate between €4,000/kg and €100,000/kg at international auctions. The risks of food fraud do not occur at auctions dedicated to these precious hypogeous fungi, organized with the participation of mycologists and industry experts (one of which is theWorld White Truffle Auction of Alba, whose proceeds are entirely donated to charities in Italy and around the world).

Food frauds  are unfortunately very common in food products claiming the presence of truffles, sometimes specifying a species. They are carried out:

• with the addition of synthetic aromas, whose molecules are almost identical to some volatile organic compounds (volatile organic compounds, VOCs) natural, as well
• by adulteration of  Tuber magnatum  Picco (or other precious truffles) with similar but less valuable and less economically valuable species, such as  Tuber borchii. (12).

Ambiguous labels

The  Food Information Regulation requires that information on labeling and advertising is fair and transparent, free from ambiguity. It expressly prohibits misleading about the identity, characteristics, and production methods of food products (EU Reg. 1169/11, articles 7.1 and 36). Both the scientific and common names of different truffle species are specified in a specific international standard. (13)

Labeling of truffles and wild mushrooms more generally – even when used as ingredients in other foods – still lacks a harmonized sector discipline. There are only some national regulations, more or less detailed (such as those of France, Italy, Spain, in decreasing order of detail).

Provisional conclusions

The truffle sector it is very interesting not only for high Italian or French cuisine, nor only for consumers with exceptional spending capacity. Instead, a greater availability is hoped for them in the coming years, thanks to the development of research on mycorrhizae. With a view to the use of truffles as food and food ingredients but also in dietary supplements and the pharmaceutical sector, where they have also revealed promising functionalities. (1)

Consumers of food products ‘with truffle’ or ‘with truffle aroma’ must in any case carefully check the list of ingredients on the label. This is to understand the actual value of products that therefore only have a higher price than others, even if they are distributed in supermarkets or  discount, rather than through sale  online (ecommerce). Keeping well in mind the distinctions between:

• truffle species mentioned in the ingredient list, and its quantity,
• ‘natural truffle aroma’, the only sign of use of truffles, instead of ‘natural aromas’ (of unknown origin) and ‘aromas’ (synthetic, zero value). (14)

The authorities  responsible for official controls should also dedicate resources to laboratory analyses, to prevent and counter food frauds in a high value-added category (therefore at greater risk than others).

Dario Dongo and Irene Giunta

Notes

(1) Dario Dongo, Irene Giunta.  Truffles, the mysterious hypogeous fungi. The ABC. GIFT (Great Italian Food Trade). 6.2.23

(2) Boutahir S. (2013). New Biotechnologies for the production of mycorrhizal plants with truffle. PhD thesis, University of Bologna, Academic Year 2012-2013

(3) Antonella Amicucci, Elena Barbieri, Valentina Sparvoli, Anna Maria Gioacchini, Cinzia Calcabrini, Francesco Palma, Vilberto Stocchi, Alessandra Zambonelli (2018). Microbial and pigment profile of the reddish patch occurring within Tuber magnatum ascomata. Fungal Biol. 2018 Dec;122(12):1134-1141. doi: 10.1016/j.funbio.2018.07.007

(4) Bach C, Beacco P, Cammaletti P, Babel-Chen Z, Levesque E, Todesco F, Cotton C, Robin B, Murat C. (2021). First production of Italian white truffle (Tuber magnatum Pico) ascocarps in an orchard outside its natural range distribution in France. Mycorrhiza. 2021 May;31(3):383-388. doi: 10.1007/s00572-020-01013-2

(5) Pennazza G, Fanali C, Santonico M, Dugo L, Cucchiarini L, Dachà M, D’Amico A, Costa R, Dugo P, Mondello L. Electronic nose and GC-MS analysis of volatile compounds in Tuber magnatum Pico: evaluation of different storage conditions. Food Chem. 2013 Jan 15;136(2):668-74. Food Chem. 2013 Jan 15;136(2):668-74. doi: 10.1016/j.foodchem.2012.08.086

(6) Bencivenga M., Baciarelli Falini L. (2012). Truffle cultivation manual. Experiences of truffle cultivation in Umbria. Umbria Region, Perugia

(7) Giusto Giovannetti. Manual for truffle cultivation. Neos Editions, Turin, 1998. ISBN 8888245588

(8) Giusto Giovannetti was also able to reactivate the metabolic function in olive trees affected by Xylella Fastidiosa, thanks to mycorrhizae.

(9) Bach, C., Beacco, P., Cammaletti, P. et al. First production of Italian white truffle (Tuber magnatum Pico) ascocarps in an orchard outside its natural range distribution in France.  Mycorrhiza 31, 383–388 (2021).  https://doi.org/10.1007/s00572-020-01013-2

(10) Jun Niimi, Aurélie Deveau, Richard Splivallo. (2021). Aroma and bacterial communities dramatically change with storage of fresh white truffle Tuber magnatum. LWT, 2021, Volume 151, 0023-6438.  https://doi.org/10.1016/j.lwt.2021.112125

(11) Vita F, Franchina FA, Taiti C, Locato V, Pennazza G, Santonico M, Purcaro G, De Gara L, Mancuso S, Mondello L, Alpi A. (2018). Environmental conditions influence the biochemical properties of the fruiting bodies of Tuber magnatum Pico. Sci Rep. 2018 May 8;8(1):7243. doi: 10.1038/s41598-018-25520-7

(12) Eva Tejedor-Calvo, Sergi García-Barreda, María Felices-Mayordomo, Domingo Blanco, Sergio Sánchez, Pedro Marco. (2023). Truffle flavored commercial products veracity and sensory analysis from truffle and non-truffle consumers. Food Control, 2023, Volume 145, 0956-7135.  https://doi.org/10.1016/j.foodcont.2022.109424

(13) UNECE (United Nations Economic Commission for Europe) Standard FFV-53 – Truffleshttps://unece.org/fileadmin/DAM/trade/agr/standard/standard/fresh/FFV-Std/English/53_Truffles.pdf UN, New York, Geneva, 2017

(14) Dario Dongo. Truffle aroma and Asian 'truffle', beware of the scam. GIFT (Great Italian Food Trade). 27.11.21