Contributions of sulfur compounds to truffle Contributions of sulfur compounds to truffle aroma aroma Changrong Ou, Xiaofen Du, Juan He, JackCzarnecki, Michael Qian Michael Qian Oregon State University Oregon State University Corvallis, OR 97331 Corvallis, OR 97331 USA USA Email: michael.qian@ oregonstate.edu Email: michael.qian@ oregonstate.edu
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Contributions of sulfur compounds to truffle Contributions of sulfur compounds to truffle aroma aroma
Changrong Ou, Xiaofen Du, Juan He, Jack Czarnecki, Michael QianMichael Qian
Oregon State UniversityOregon State UniversityCorvallis, OR 97331Corvallis, OR 97331
• Truffles are fungi, like mushrooms, but grow under ground
•• Truffle is the fungal fruiting body of fungiTruffle is the fungal fruiting body of fungi
•• They grow slowly underground for months and are only fully They grow slowly underground for months and are only fully fragrant for a week or so, as they ripen near the end of their fragrant for a week or so, as they ripen near the end of their maturation processmaturation process
•• There are hundred truffle species, only a few (mostly in genus There are hundred truffle species, only a few (mostly in genus TuberTuber) are highly prized for human consumption) are highly prized for human consumption
•• Size and shape varySize and shape vary
Truffles form a symbiotic relationship with their Truffles form a symbiotic relationship with their environmentenvironment•• Truffle fungi grow symbiotically with the roots of certain treesTruffle fungi grow symbiotically with the roots of certain trees
–– oak, elm, chestnut, pine and willow.oak, elm, chestnut, pine and willow.
•• The tree provides the fungus with carbohydrates produced The tree provides the fungus with carbohydrates produced through photosynthesis through photosynthesis
•• in turn, fungus acts as an expanded fine root system for the in turn, fungus acts as an expanded fine root system for the tree, absorbing water and mineral nutrients through its very fintree, absorbing water and mineral nutrients through its very fine e root system root system
Culinary Treasures
Black Truffle (Tuber melanosporum) Black Truffle (Tuber melanosporum)
•• Black truffle (Black truffle (Tuber melanosporumTuber melanosporum) grows exclusively with oak ) grows exclusively with oak treetree
•• France accounts for 45%, Spain 35%, Italy 20%France accounts for 45%, Spain 35%, Italy 20%
•• Black truffles sell between$130Black truffles sell between$130––$380 per pound$380 per pound
White Truffle (Tuber magnatum) White Truffle (Tuber magnatum)
•• The White truffle (The White truffle (Tuber magnatumTuber magnatum) ) comes from Northern and Central comes from Northern and Central Italy. Most famously, around Alba of Italy. Most famously, around Alba of Italy. Italy.
•• Growing symbiotically with oak, Growing symbiotically with oak, hazel, poplar and beech hazel, poplar and beech
•• Harvest from October and NovemberHarvest from October and November
The The Tuber magnatumTuber magnatum truffles sell $2,200truffles sell $2,200-- $1,000 /lb $1,000 /lb
The record price paid for a single white truffle was $330,000 The record price paid for a single white truffle was $330,000 (3.3(3.3 lb)lb)
Oregon TruffleOregon Truffle
•• White truffle varieties:White truffle varieties:–– Tuber oregonenseTuber oregonense–– ripens in December through Februaryripens in December through February
–– Tuber gibbosumTuber gibbosum–– harvest in May and Juneharvest in May and June
•• Black truffle Black truffle –– Leucangium carthusianumLeucangium carthusianum–– has a distinctively has a distinctively fruity aromafruity aroma
Habitat of Oregon TruffleHabitat of Oregon Truffle
•• All three of OregonAll three of Oregon’’s s commerciallycommercially--harvested truffle harvested truffle species grow in young Douglas species grow in young Douglas fir stands at low elevations. fir stands at low elevations.
•• These stands span the region These stands span the region from northern California to from northern California to southern British Columbia, west southern British Columbia, west of the Cascades Mountain of the Cascades Mountain Range. Range.
Habitat of Oregon TruffleHabitat of Oregon Truffle
•• White truffles are found most White truffles are found most abundantly in former pasture or abundantly in former pasture or agricultural land that has been agricultural land that has been planted with young Douglas fir. planted with young Douglas fir.
•• Black truffles are widely distributed Black truffles are widely distributed in plantations near streams, but also in plantations near streams, but also on reforested hillsides.on reforested hillsides.
••
••The distribution of the three truffle The distribution of the three truffle species overlaps considerablyspecies overlaps considerably
•• Roughly 100,000 acres of forest are suitable for white and blacRoughly 100,000 acres of forest are suitable for white and black k truffles in Oregontruffles in Oregon
•• Less than 2% of this acreage is being harvested for trufflesLess than 2% of this acreage is being harvested for truffles
Female Pig Has Been Historically Used for Truffle Female Pig Has Been Historically Used for Truffle HuntingHunting
sulfides, and androstenol from truffle are thought be responsible
Pigs do eat truffles!
Trained Dog Works BetterTrained Dog Works Better
Aroma compounds in TruffleAroma compounds in Truffle
•• Volatile sulfur compounds are primarily responsible for the Volatile sulfur compounds are primarily responsible for the characteristic aroma of white truffle aromacharacteristic aroma of white truffle aroma
•• In addition to sulfur compounds found in white truffle, In addition to sulfur compounds found in white truffle, methylthio acetate and ethyl 3methylthio acetate and ethyl 3--(methylthio)propanoate also (methylthio)propanoate also contribute to black truffle aromacontribute to black truffle aroma
•• Esters provide additional fruity aroma to Oregon black truffleEsters provide additional fruity aroma to Oregon black truffle