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Citrus oils





Bouquetier de Nice à fleurs doubles Extraction and composition Kaffir lime leaves
Users
Oil names
Table lay-out and abbreviations
Table of citrus oils
Bouquetier de Nice à fleurs doubles
© Petr Broža
Citrus hystrix, leaves
© Citrus Clonal Protection Program










Extraction and composition


Mediterranean mandarin, Citrus reticulata var. deliciosa


Citrus latifolia, Persian lime © C. Jacquemond / INRA


Citrus limetta

Citrus oils are chemical compounds which contain the flavour and aroma of the fruit in a concentrated form. These aromatic substances are seldom real oils. The term 'oil' is used because the first essences produced by a similar process resembled oil in composition. The finest oils are produced from flowers. Citrus oils are most plentiful in the oil glands of fruit peel. Some oil is also extracted from fruit pulp and seeds, and another type from young leaves and twigs. 

The largest amount of citrus oil for commercial use is made by vapour distillation from the peel and solids left over from juice extraction. Bigarade oil is produced from the outer part of the peel by cold expression. Petitgrain oil is extracted from leaves, twigs and small unripe fruit by steam distillation, the method also used for obtaining Neroli oil from flowers. Genuine orange-flower water is a by-product of steam distillation.

Only the water-soluble and volatile parts of citrus oil can be extracted by steam distillation. Many solid compounds that are valuable in perfumes and aromatherapy such as tannins, resinoids and waxy ingredients, can only be obtained by solvent extraction. Alcohol and hexane are the most common solvents used. Solid or semi-solid oils include resinoids, concretes and absolutes. Several cycles of alcohol extraction may be needed to produce an absolute. The alcohol is removed from the final product by evaporation and vacuum treatment. 

Whether liquid, semi-solid or solid, all citrus oils can be dissolved in pure alcohol, fats and fixed vegetable oil but not in water. Unlike vegetable oils, such as olive and avocado, liquid citrus oils evaporate completely when exposed to air leaving no oily residue behind.  

Users
The biggest user of citrus oils is the food industry. Citrus oils are the main flavour in a large number of internationally marketed soft drinks. Citrus oils impart their flavour to beverages, sweets, jams, cookies and confectionery. Oils form an important part of the aroma of many well-known citrus liqueurs, such as Grand Marnier, Cointreau, Triple Sec and Curaçao. Chewing gum, gelatins and ice cream are among other products in which citrus flavours are commonly used. Oils diluted to suitable strengths and flower-water are sold in pharmacies and food stores; they can be used in cooking and baking when certified for food use. After oil extraction the peel of grapefruit, pomelo and lemon can be treated to yield pectin and citric acid. Both are used in the preparation of jams and marmalade to improve structure and preservation.

Other important users of citrus oils are the chemical and pharmaceutical industries. Oils are used for flavouring pharmaceuticals and as a scent in toothpaste, soap, shampoo, washing powder and other household products.
Citrus aurantium var. bigaradia 'Apepu' © C. Jacquemond / INRA

'Lisbon' lemon


Citrus aurantium 'Bouquetier' flower The third important sector of citrus oil use is the production of perfumes and cosmetics. The Neroli, Bigarade and Petitgrain oils of sour orange and bergamot are irreplaceable in the preparation of the finest perfumes, colognes and after-shaves. Their fragrance consists of dozens of chemical compounds. Even the most modern technology cannot reproduce the exact combinations in them. Slightly cheaper citrus oils are used in creams, lotions and other beauty-care products.


The fourth user of citrus oils is aromatherapy. Compared to the first three aromatherapy is economically less important, but to an average consumer perhaps more familiar. The oils used in aromatherapy are obtained from flowers and young twigs and leaves by steam distillation and from outer peel by cold expression. The therapeutic value of citrus oils has been known as long as the fruit. Besides eating the fruit to prevent disease citrus oils have numerous uses for improving physical and mental health. More information is available in books and on the Internet using aromatherapy as the keyword.  Citrus aurantium, Sour orange flower


Confusion in the names
Citrus aurantium, sour orange

Citrus latifolia, 'Bearss' lime

Bergamot, Citrus aurantium ssp. bergamia
A word of caution: citrus oils, which in aromatherapy are called essential oils (the product is the same), can have various names that are often carelessly used interchangeably. The fact that several oils with different characteristics and a different name can be obtained from the same plant using different extraction methods can be confusing. An example: sour orange oil is made from common, bittersweet and perfumery varieties. Raw materials range from buds, flowers, peel, young leaves and twigs to whole small immature fruit. Oils can be extracted by steam distillation or cold expression. The number of possible combinations each with a different name is 18, all from sour orange.

The fact that bergamot is botanically also a sour orange increases the number of combinations and thus the chance of confusion. Taking further into consideration that some sour orange oils are erroneously marketed as blood orange oils there is a considerable possibility for mistake. The best guide is always the botanical name. If the label says Citrus aurantium or Citrus aurantium var. amara it is quite possible that what you get is a genuine sour orange oil. The names Neroli, Bigarade and Petitgrain also point towards sour orange, especially in combination with the name Citrus aurantium. Citrus sinensis is the Latin name of sweet orange. While it perhaps has a more pleasant fragrance, it does not possess all the therapeutic and aromatic properties of sour orange. More detailed information can be found in the description of Sour orange, Bittersweet orange and Perfumery varieties
 

Table lay-out and abbreviations
The table below is a compilation of the most common citrus oils.
Column 1 The starting point is always the botanical name of the plant .
Column 2 The common name serves as a link to a more detailed description of the plant.
Column 3
 
Shows the trade names of the most common oils produced from each plant. It is possible that oils made from different parts of the plant or by different methods have the same name.
Column 4 Has the raw material used for each oil.  
Column 5
 
Shows the extraction methodSome of the rarer methods such as enfleurage, the absorption of oil into fat, have been left out of this presentation.  
Column 6
 
 
Describes the main users of each oil type:
ALC
alcohol industry, ARO aromatherapy, CHE chemical industry, COS cosmetics,
FOO food industry, PHA pharmaceutical industry and PER perfume industry. 

The titles bergaptenless, monoterpeneless and terpeneless refer to oils that have these substances chemically removed as they can be harmful if ingested in large quantities. These oils are used in food and alcohol products.

There is a more detailed description of Neroli, Bigarade and Petitgrain oils at the bottom of the table.



This table is optimised for 1024 x 768 resolution. Smaller resolutions may cause the lines to overlap.

C I T R U S   O I L S
Plant
Botanical name
Fruit
Link to description
Oil
Trade name
Raw material
Part of the plant used
Process

Main users
See abbreviations below
Citrus aurantiifolia Lime
Lime

Lime
 

Outer peel of medium ripe fruit

Crushed fruit
 

Cold expression

Steam distillation
 

ARO, PER

COS, FOO
 
Citrus aurantium Sour orange
Neroli

Citrus aurantium absolute

Neroli bigarade

Neroli petitgrain
 

Flowers

Flowers

Outer peel of medium ripe fruit

Leaves and twigs
 

Steam distillation

Solvent extraction

Cold expression

Steam distillation
 

ARO, FOO
, PER

ARO, PER

ARO,
FOO

ARO, FOO
 
Citrus aurantium
var. bigaradia
Bittersweet orange
Bigarade

Bigarade terpeneless

Petitgrain

Petitgrain terpeneless


Outer peel of nearly ripe fruit

Outer peel

Leaves and twigs

Leaves and twigs


Cold expression

Cold expression

Steam distillation

Steam distillation

ARO, PHA

ALC, FOO

ARO

FOO 

Citrus aurantium 'Bouquetier'
 

Perfumery varieties
 

Neroli

Citrus aurantium absolute
 

Flowers

Flowers
 

Steam distillation

Solvent extraction
 

PER, ARO

PER, ARO
 
Citrus aurantium
ssp. bergamia
Bergamot
Bergamot

Bergamot bergaptenless


Bergamot petitgrain

Bergamot


Outer peel of medium ripe fruit

Outer peel of medium ripe fruit

Leaves, twigs and unripe peel

Crushed fruit
 

Cold expression

Cold expression

Steam distillation

Steam distillation
 

ARO, PER

ALC, FOO

PER, Eau de Cologne

CHE, COS
 
Citrus hystrix Kaffir lime
Combava

Combava petitgrain
 

Nearly ripe peel, pulp and leaves

Leaves and twigs
 

Steam distillation

Steam distillation
 

COS,
FOO

COS
 

Citrus limetta
   

Limetta
 

Limetta
 

Outer peel
 

Cold expression
 
 
Citrus limon Lemon
Lemon

Cedro oil

Lemon petitgrain


Outer peel of
fresh ripe fruit

Bergaptenless and terpeneless

Leaves, twigs and small raw fruit
 

Cold expression

Cold expression

Steam distillation


ARO,
CHE, COS, PER, PHA

ALC, FOO

CHE, COS, PER, PHA

Citrus medica Citron
Cedrat

Cedrat

Cédrat petitgrain
 

Flowers

Peel

Leaves and twigs
 

Steam distillation

Cold expression

Steam distillation
 

PER

ARO, FOO, COS

FOO, PER
 
Citrus paradisi Grapefruit
Grapefruit


Grapef.monoterpeneless


Outer peel of
fresh ripe fruit

Peel


Cold expression

C. expr./distillation


ARO

ALC, FOO, "Tonic"-waters

Citrus reticulata Mandarin
Mandarin

Mandarin terpeneless

Mandarin petitgrain
 

Outer peel of fresh ripe fruit

Outer peel

Leaves and twigs
 

Cold expression

Cold expression

Steam distillation
 

ARO, PER

ALC, FOO

COS, PER
 
Citrus sinensis Sweet orange
Sweet orange

Sweet orange

Neroli Portugal
 

Outer peel of ripe fruit

Crushed fruit

Flowers
 

Cold expression

Steam distillation

Steam distillation
 

ARO, COS, PER

CHE

PER
 

Main users
ALC alcohol industry,  ARO aromatherapy,  CHE chemical industry, COS cosmetics,  
FOO food industry, PHA pharmaceutical industry,  PER perfume industry.
 

Neroli
oil is usually made from buds and flowers of sour orange or sweet orange. The finest Neroli is made by slow cold expression.
Usually Neroli is made by steam distillation. Genuine orange-flower water is a by-product of this steam distillation. Neroli oil is always expensive.
If you get cheap Neroli it is either adulterated with cheaper oils or synthetic. The most expensive Neroli comes from the perfumery varieties,
which are grown only for Neroli oil.


Bigarade
 
is made from the outer part of the peel of usually medium ripe fruit by cold expression.


Petitgrain oil can have varying compositions according to the fruit used and the purpose for which the oil is made. 
Most often it is made of fresh leaves and twigs of the same year. Sometimes whole small raw fruit or peel of raw fruit is added.
Petitgrain is always made by steam distillation. 

In addition to the oils above, less expensive oils are made by steam distillation from the pulp and peel left over from

industrial juice extraction
. These oils are often sold by the name of the fruit (lime oil, grapefruit oil) but the compounds,
which can be harmful when ingested
(bergapten, some terpenes), have been chemically removed.
These oils are used by the food industry to flavour soft drinks, chewing gum,   
sweets, marmalades, confectioneries and citrus liqueurs.
 







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Page up-dated 20 November 2009


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