Lemon oil is extracted from oil-containing cells in the skin. A machine breaks up the cells, and uses a water spray to flush off the oil. The oil/water mixture is then filtered and separated by centrifugation.
Industrial
Lemons were the primary commercial source of citric acid before the development of fermentation-based processes.
Aroma
Lemon oil may be used in aromatherapy. Lemon oil aroma does not influence the human immune system, but may contribute to relaxation.
Other
One educational science experiment involves attaching electrodes to a lemon and using it as a battery to produce electricity. Although very low power, several lemon batteries can power a small digital watch. These experiments also work with other fruits and vegetables.
Lemon juice may be used as a simple invisible ink, developed by heat.
Lemon juice can be used to increase the blonde colour of hair, acting as a natural highlight after the moistened hair is exposed to sunlight. This is due to the citric acid that acts as bleach.
