Table 1 Aroma profiles of truffles

T. nivea, P. lefebvrei, T. boudieri

Negev desert

HS-SPME–GC–MS

Hexanal and 1-octen-3-ol were key volatiles in T. boudieri and T. nivea fruiting bodies. P. lefebveri with weak aroma exhibits low levels of both volatiles. T. nivea contains dimethyl disulfide, methional, benzaldehyde and benzenacetaldehyde, 3-methylbutanal and 2-methylbutanal. Total volatile levels in T. nivea are about twofold higher than in T. boudieri. T. boudieri has around tenfold higher volatile levels than in P. lefebveri

[25]

T. formosanum

n.g.

SPME–GC–MS

In T. formosanum mycelium, a total of 23 VOCs was identified, then quantified. Consequently, dimethyl sulfide, isopropyl alcohol, 2-butanone, ethanol, and 1,3-pentadiene were revealed as the key aroma contributors in T. formosanum

[26]

T. melanosporum

Truel, Spain

HS-SPME–GC–MS

The effect of freezing on the aroma of T. melanosporum ascocarps was evaluated. The frozen samples were richer in diacetyl, 1-octen-3-one, 1-octen-3-ol, 2-methylisoborneol, and dimethyltrisulphide. 1-octen-3-one was the only aroma contributor which significantly increased after the freezing process and was suggested as a potential marker for the freezing

[27]

T. magnatum, T. melanosporum, T. aestivum

Italy

HS-SPME–GC–MS

Aroma active compounds in 20 raw truffles, truffle-flavored oils, and truffle sauces were profiled. 1-octen-3-ol was detected in high amounts in raw T. melanosporum. Bis(methylthio)methane was mainly characterized both in sauces and naturally and artificially made oils flavored with T. melanosporum.

[28]

T. liyuanum

China

HS-SPME–GC–MS

A total of 57 volatiles in T. liyuanum were detected for the first time. Among them, 3-octanone, phenylethyl alcohol, isopentana, and methylbutana were the key contributor to the aroma. This study also suggested the optimal extraction condition for the screening of aroma active compounds: sample amount, 2 g; extraction temperature, 80 °C; extraction time, 40 min; SPME fibre of carboxen/PDMS

[29]

T. borchii

Italy and New Zealand

HS-SPME–GC–MS/O, GC-R, AEDA

The contribution of thiophene derivatives contributed to human-sensed aroma of T. borchii was investigated. A total of eleven key aroma active compounds, which showed an FD factor higher than 5, were identified. The thiophene derivatives, in particular 3-methyl-4,5-dihydrothiophene, were the main contributors to the human-sensed aroma of T. borchii

[32]

T. sinensis, T. sinoalbidum, T. sinoexcavatum

China

SPME–GC–MS/O/FPD, aroma recombination

A total of 44, 43, and 44 volatiles were detected in T. sinensis, T. sinoalbidum, and T. sinoexcavatum, respectively. Among them, 24 compounds were suggested as the important contributors to the overall aroma of three truffle varieties which present flora, mushroom, and sweet odor

[24]

T. melanosporum, T. indicum

Truel, Spain

HS-SPME–GC–MS/O

This study found the aromatic marker for distinguishing between T. indicum and T. melanosporum. 1-Octen-3-one and 1-octen-3-ol, the main aroma contributors in T. indicum, presented the modified frequencies (MF) of 82% and 69%, respectively, while both compounds in T. melanosporum exhibited the low MF (< 30%). In T. melanosporum, ethyl isobutyrate, ethyl 2-methylbutyrate, and isopropyl acetate contributed significantly to aroma with the high MF (> 70%)

[33]

T. himalayense, T. indicum, T. sinense

Yunnan and Sichuan, China

HS-SPME-GC–O

Twelve aroma active compounds, included 3-(methyl-thio)propanal, 1-octen-3-ol, 3-methylbutanal, 2-nonenal, benzeneacetaldehyde, hexanal, dimethyl sulfide, 3-methyl-1-butanol, 3-octanone, benzaldehyde, 2-phenylethanol, and dimethyl disulfide, were identified in T. himalayense, T. indicum, and T. sinense fruiting bodies. Among them, 3-(methylthio)propanal, 3-methylbutanal, and 1-octen-3-ol were the key contributors to the aroma in these three species

[34]

T. magatum pico, T. uncinatum

n.g.

HS-SPME–GC–MS/O

More than 40 odorants were evaluated as truffle volatiles for the first time. 2,3-Butanedione, 2- and 3-methylbutanal, 3-(methylthio) propanal, and bis(methylthio)-methane showed the highest FD factors in T. magnatum pico, while 2,3-butanedione, phenylacetic acid, and vanillin in T. uncinatum. 3-Methylbutanal, 3,4-dihydro-2-(H)pyrrol (1-pyrroline), and bis(methylthio)methane exhibited the highest OAV in T. magnatum pico. In T. uncinatum, 1-pyrroline and 2,3-butanedione revealed the highest OAVs

[20]

T. japonicum, T. magnatum, T. melanosporum

T. japonicum from Hyogo and Tochigi, Japan, T. magnatum from Italy, T. melanosporum from France

HS-SPME–GC–MS/O

This study compared the chemical composition of J. Japonicum (Japanese white-colored truffle) ascomata with T. magnatum and T. melanosporum. 1-octen-3-ol and 3-methyl-2,4-dithiapentane were highly contributed to aroma of T. japonicum. In addition, 3-methyl-2,4-dithiapentane was detected as a characteristic sulfur volatile in T. japonicum while 2,4-dithiapentane is the key odorant of T. magnatum

[35]

T. melanosporum

Sichuan, China

HS-SPME–GC-FID/O, AEDA, aroma evaluation method

The novel method exhibited their potentials as a viable alternative to the traditional method. A total of seven key volatiles in T. melanosporum (2,5-dimethylpyrazine, 3-butyl-2,5-dimethylpyrazine, 3-ethyl-2,5-dimethylpyrazine, 3-methyl-1-butanol, 3-(methylthio)-1-propanol, benzeneacetaldehyde, and phenylethyl alcohol) identified by the traditional method using GC–O, was also characterized by the new method along with additional two important aroma contributors, 2,3-butanediol and trimethylpyrazine

[31]

T. magnatum Pico

Alba and San Miniato, Italy

PTR-TOF–MS

29 volatiles were identified in this study for the first time. The VOC profiles enabled to differentiate between summer and fall/winter T. magnatum production as well as their geographical origin (Alba and San Miniato)

[36]

Chinese black and white truffle

Yunnan Province, China

DSE-SAFE coupled with GC × GC/HR-TOF–MS, electronic nose

In Chinese black truffle (BT), 14 alcohols and phenols, 13 aldehydes, 10 acids, 6 esters, 6 ketones, 5 furans and furanones, 2 hydrocarbons, and 2 sulfur-containing compounds were identified. In the white truffle (WT), 12 aldehydes, 10 acids, 9 alcohols and phenols, 5 sulfur-containing compounds, 4 furans and furanones, 3 esters, 3 ketones, and 1 hydrocarbon, were identified. More sulfur-containing compounds were detected in WT in terms of both amounts and contents

[40]

T. magnatum

Oils supplied from Germany, Italy, Switzerland, and UK; Fruiting bodies from Piedmont, Italy/Valjevo, Serbia/Sellye, Hungary/Piedmont, Italy

GC–MS, GC-IRMS

The differences among home-made and commercial truffle oils were evaluated. The δ13C value of 2,4-dithiapentane in most flavored oil samples was obtained by GC-IRMS and GC–MS. GC-IRMS could not distinguish between synthetic and natural flavors, while the metabolic profiling using GC–MS revealed that two sulfur containing volatiles, dimethyl sulfone and dimethyl sulfoxide, were exclusively detected in commercial oils

[22]

T. magnatum Pico

Italy

HS-SPME MDGC–C–IRMS

Bis(methylthio)methane was analyzed to discriminate natural and synthetic aroma. The Stable isotope ratio (δ13C) values of this volatile compound in genuine truffles attained between − 43 and − 34‰, while those from synthetic aroma exhibited more negative values

[42]