Olfactory perception of cysteine-S-conjugates from fruits and vegetables.
Volatile sulfur compounds have a low odor threshold, and their presence at microgram per kilogram levels in fruits and vegetables influences odor quality. Sensory analysis demonstrates that naturally occurring, odorless cysteine- S-conjugates such as S-( R/ S)-3-(1-hexanol)- l-cysteine in wine, S-(1-propyl)- l-cysteine in onion, and S-(( R/ S)-2-heptyl)- l-cysteine in bell pepper are transformed into volatile thiols in the mouth by microflora. The time delay in smelling these volatile thiols was 20-30 s, and persistent perception of their odor occurred for 3 min. The cysteine- S-conjugates are transformed in free thiol by anaerobes. The mouth acts as a reactor, adding another dimension to odor perception, and saliva modulates flavors by trapping free thiols.
Starkenmann
Christian
C
Corporate R&D Division, Firmenich SA, P.O. Box 239, CH-1211 Geneva 8, Switzerland. christian.starkenmann@firmenich.com
Le Calvé
Benedicte
B
Niclass
Yvan
Y
Cayeux
Isabelle
I
Beccucci
Sabine
S
Troccaz
Myriam
M
D005260:Female; D005638:Fruit / Q000737:chemistry*; D016967:Fusobacterium nucleatum / Q000378:metabolism; D006801:Humans; D008297:Male; D009812:Odorants; D012463:Saliva / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013457:Sulfur Compounds / Q000737:chemistry*; D014675:Vegetables / Q000737:chemistry*; D014835:Volatilization
D013438:Sulfhydryl Compounds; D013457:Sulfur Compounds