Citrus peel oils
The fruits
The most studied citrus species include sweet orange (Citrus sinensis), mandarin (Citrus reticulata), grapefruit (Citrus paradisi), lemon (Citrus limon), lime (Citrus aurantifolia), bitter orange (Citrus aurantium) and bergamot (Citrus bergamia).[1] Of the peel oils, sweet orange peel oil is the most important, followed by lemon peel oil.[3]
The bergamot is a small tree whose fruits are inedible; only the oil pressed from their peel is of real value. In the mid-20th century the tree grew almost only in a narrow coastal strip of southern Calabria, Italy. The lemon tree is probably native to East India and Burma, and it reached Europe with crusaders returning in the 12th century.[3]
Oils from the flowers and leaves of citrus trees are separate materials, not peel oils. Neroli oil, for example, comes from the flowers of the bitter orange.[2]
How the oils are made
Pressing, or expression, is used only for the peels of citrus fruits and can be done by hand or by machine. Pressed oils are not entirely volatile but are still counted as essential oils. These so-called cold-pressed oils are among the most basic natural perfume materials and can be used in perfumes and flavours just as they come from the fruit.[3]
Citrus oils can also be obtained by steam distillation, from the peel as well as from the flowers and leaves; pressing is not used for flowers and leaves.[1] Mexican lime oil is often made by spinning the liquid from whole fruits in fast centrifuges, which quickly separates the oil from the acid juice. In the mid-20th century pressed lime oils were more expensive than distilled ones because they gave lower yields.[3]
Under the European Pharmacopoeia, an essential oil may be obtained only by distillation or cold pressing, so a solvent extract of citrus peel should not be called an essential oil.[1]
Composition
Volatile substances make up 85 to 99% of a citrus peel oil, typically more than 200 compounds. The most abundant is always limonene, usually about 60 to 95% of the oil; in lemon oil it can fall to 48% and in bergamot oil to 30%. Other components occur in much smaller amounts: lemon oil, for example, contains up to about 2.9% geranial and 1.5% neral, the two components of citral, far more than mandarin oil does.[1]
Scent and uses
Citrus oils are widely used to make natural fruity perfumes and as flavourings in food, medicines and cosmetics.[1] Bergamot oil, for example, is a green or olive-green liquid with an extremely rich, sweet-fruity first impression; it is used extensively in perfumery, especially in citrus colognes and other classic perfumes.[3]
Storage
Citrus peel oils are rich in limonene, which oxidises especially easily. Heat speeds up oxidation; an oxidised oil smells less fresh and is more likely to cause a skin allergy. Kept in a refrigerator, essential oils last about twice as long.[4]
Safety
Some peel oils contain phototoxic furocoumarins such as bergapten, mainly the pressed or solvent-extracted oils of bergamot, lime and bitter orange. Such compounds have also been reported in lemon oil, but not in sweet orange or mandarin peel.[1] In fragrance products, furocoumarins have caused phototoxic reactions (reactions to light) with skin redness followed by dark patches, known as berloque dermatitis. Limits now apply, and such reactions are rare.[5]
At most 2% pressed lemon oil on the skin is recommended, to avoid a phototoxic reaction. Steam-distilled lemon oil is not phototoxic.[6] In the European Union, furocoumarins may not be added to cosmetics; only their normal content in the natural essences used is allowed. In sun-protection and tanning products they must stay below 1 mg/kg.[7]
Oxidised limonene is one of the most common contact allergens.[5] In the European Union, lemon, orange and bergamot peel oils must appear in a cosmetic's ingredient list above a set level. The level is 0.001% for products left on the skin and 0.01% for products that are rinsed off.[8]
Products containing them
Sources
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 M. Carmen González-Mas et al., Volatile Compounds in Citrus Essential Oils: A Comprehensive Review. Frontiers in Plant Science 10 (2019), 12, doi 10.3389/fpls.2019.00012.
- ↑ 2.0 2.1 Jugreet B. Sharmeen et al., Essential Oils as Natural Sources of Fragrance Compounds for Cosmetics and Cosmeceuticals. Molecules 26 (2021), 666.
- ↑ 3.0 3.1 3.2 3.3 3.4 Steffen Arctander, Perfume and Flavor Materials of Natural Origin, Elizabeth, NJ, 1960: Essential Oil; Bergamot Oil; Lemon Oil; Lime Oil.
- ↑ Robert Tisserand, Lemon on the rocks: keep your essential oils cool. 26 July 2013.
- ↑ 5.0 5.1 Scientific Committee on Consumer Safety (SCCS), Opinion on fragrance allergens in cosmetic products, SCCS/1459/11, adopted 26–27 June 2012.
- ↑ AromaWeb, Lemon Essential Oil. Retrieved 8 November 2026.
- ↑ European Commission, CosIng, Annex II: list of substances prohibited in cosmetic products. Retrieved 9 November 2026.
- ↑ European Commission, CosIng, Annex III: list of substances which cosmetic products must not contain except subject to the restrictions laid down. Retrieved 9 November 2026.