Fragrances Flashcards
what are essential oils?
concentrated extracts from plants and are a mixture of organic compounds.
properties of essential oils
volatile and non-water soluble aroma compounds
examples of essential oils
- limonene from lemons
- lavandulol from lavender
- geraniol from geraniums
uses of essential oils
- cosmetics
- flavouring
- perfumes
- cleaning products
extracting essential oils in the lab
- oil must be volatile so it can be carried over by steam
- water added to produce steam
- oil and water do not mix and can be easily separated and the oil collected
- oil extracted by solvent extraction
what are terpenes?
- key components in most essential oils
- unsaturated compounds formed by joining together isoprene units.
isoprene formula
2-methylbuta-1,3-diene
molecular formula for isoprene
C5H8
general formula for isoprene
(C5H8)n where n is the number of linked isoprene units
how to work out number of isoprene units
divide the total number of carbons by 5
two structures of terpenes
linear or cyclic terpenes
myrcene
component of plants including bay, ylang-ylang and thyme
carotene
linear terpene found in carrots
made up of 8 isoprene units
limonene
cyclic terpene found in lemons/skin of citrus fruits
made up of 2 isoprene units
oxidation of terpenes
terpenes can be oxidised within plants producing some of the compounds responsible for the distinctive aroma of spices
why would we want to prevent oxidation of terpenes?
can alter the properties and smell
what can be used to prevent oxidation of terpenes
being kept in brown bottles
brown glass bottles filter light, preventing chemicals degrading when exposed to light.
what is a terpanoid
an oxidised terpene
