Geraniol is a monoterpenoid and an alcohol. It is the primary part of rose oil, palmarosa oil, and citronella oil (Java type). It also occurs in small quantities in geranium, lemon, and many other essential oils. It appears as a clear to pale-yellow oil which is insoluble in water, but soluble in most common organic solvents. It has a rose-like odor, for which it is commonly used in perfumes. It is used in flavors such as peach, raspberry, grapefruit, red apple, plum, lime, orange, lemon, watermelon, pineapple and blueberry.
Use
Research has shown geraniol to be an effective plant-based mosquito repellent. On the other hand, it can attract bees as it is produced by the scent glands of
honey bees to help them mark nectar-bearing flowers and locate the entrances to their hives.
Although geraniol and other flavor compounds are found naturally in well aged tobacco, geraniol is listed in a 1994 report from cigarette companies as one of the 599 additives to cigarettes to improve their flavor.
Biochemistry
The
functional group based on geraniol (essentially geraniol lacking the terminal -OH) is called
geranyl. It is important in
biosynthesis of other
terpenes. It is a by product of the metabolism of
sorbate and thus is a very unpleasant contaminant of wine if bacteria are allowed to grow in wine.
Reactions
In
acidic solutions, geraniol is converted to the cyclic terpene
alpha-terpineol.
Health and safety
Geraniol should be avoided by people with perfume allergy.
References
See also
- Citral, the corresponding aldehyde;
- Nerol, the double bond isomer;
- Rhodinol, a related terpene alcohol.
