The lipid of green arabica coffee beans averages some 15% whilst robusta coffees contain much less, around 10%. Most of the lipids – coffee oil – are located in the endosperm.
Coffee oil when isolated from roasted coffee does possess considerable of the aromatic and flavoring constituents of coffee.
Several commercial instant coffees have coffee oil in quantities less than 0.5% sprayed upon them before packing. This provides an excellent level of smell in the jar.
Coffee oil is composed mainly of triglycerides with fatty acids. Compared with typical vegetable oil, coffee oil has a low proportion of triglycerides and a high proportion of unsaponifiable matter.
Most of the fatty acids of coffee oil are saturated acids, palmitic, and stearic and unsaturated acids: mono-unsaturated, oleic acid, and poly-unsaturated, linolenic acid.
The relatively large unsaponifiable fraction is rich in diterpenes of the kaurane family mainly cafestol, kahweol, and 16-O-methylcafestol.
Cafestol but not kahweol is now known to be responsible for the reversible hypercholesterolaemic (blood cholesterol raising) and hypertriglyceridaemic (blood triglycerol raising) effects of boiled coffee as commonly as commonly consumed in Italia and Scandinavia.
Coffee oil
