PERFUMES AND ESSENTIAL OILS


OUTLINE:
Question: Why is one method preferred over another?
  1. Cost
  2. Quality of product
  3. Availability of product
Commercial essential oils: Introduction Reading
CHAPTER 8 IN THE TEXT


It is difficult to know when people first started to use perfumes. The Egyptians had become skilled perfumers over 5000 years ago. The Hebrews learned from them. Recipes for perfumes and incenses are found in the Torah or Jewish law.
Perfumes also showed up very early in the Orient. The Japanese and Chinese both developed perfumes and incenses as well.
Perfumery reached its pinnacle during the Roman Empire. They perfumed everything. After the fall of the Roman Empire, perfumery in Europe just about disappeared. The Arabs maintained these skills and improved them. At the time of the Crusades, the crusaders not only discovered spices, but also perfumes. The French developed the art of perfumery even more.
There is a lot of folklore associated with perfumery. Many of the recipes for the best perfumes are guarded trade secrets.
In the last few years, all major perfumers have a staff of organic chemists and perfume compounding is no longer an art, but a science.

How perfumes are made
All perfumes originally came from plants (or animals). The material could be used directly (as frankincense and myrrh) or extracted in some way. The challenge was (and is) how to remove the essential oils from the plant material without changing the composition.
Other materials known as fixatives retard and modify the evaporation of volatile essential oils.

Odorants are what give the perfumes the characteristic odor. There are five types: concretes, absolutes, distilled and fractionally distilled oils, expressed oils and tinctures.
Many factors determine which method is used. Among these are cost, quality of essence, and use of the product. Concretes are the purest of the natural odorants. They are obtained by using a hydrocarbon solvent to dissolve the essential oils out of the plant. The liquid is then removed under vacuum by mild heating.

Absolutes are extracted from the non-volatile materials with alcohol. The alcohol is removed under vacuum also. The alcohol is recovered and used in colognes and lotions.
Enfleurage is one method for making concretes and absolutes. The petals are pressed onto a coating of pure lard and changed often. After several days the lard has dissolved the released essential oils. The essential oils are then removed from the lard with alcohol. The lard is pomade. After extraction, the lard is used to make soaps etc.
It is possible to make exceedingly fine fragrances in this way, but it is also very expensive. Today, this process is still carried out in France, but more commonly in the Balkans and the Near East in a few places where labor is much cheaper. Grasse in Provence used to be the center for this industry.
One pound of concentrate (or absolute) is worth thousands of dollars.

Rose oil or attar of roses (also otto). In the 1960's sold for more than $1000 per pound. From Rosa damascena(or R. albaand R. centifolia) in the late bud stage. These are small shrubs with not too showy flowers. Done from April to July. 0.5 g from about 1000 g of flowers. The oil is about 40-65% citronellol but many minor components that are essential for good rose quality.
In fact, some are more important (at less than 0.1%) than the citronellol. Rose oils are usually extended before marketing.

Rose (Rosa damascena)

Jasmine (Jasminum grandiflorum, Oleaceae) is also used in southern France. From July to October. 5000 flowers makes about 1 lb of flowers. More than 300 lbs. of flowers are required to make 1 lb. of oil. The flowers are picked at daybreak for best odor.
Today this oil is mostly obtained by solvent extraction because of price.

Jasmine

Violet (Viola odorata, Violaceae) is also from Grasse, Toulouse and from the Taggia valley in Italy. Grown under shaded conditions. January to April. The flowers are picked at night or early morning. 1000 lbs. of flowers gives 1 lb. of oil.

Violets

Steam distillation (or codistillation with water) is another gentle and widely used process. Much less expensive than enfleurage. The oils are insoluble and when the steam-oil mixture is condensed, the oil can be removed. The most volatile compounds come over first and some fractionation is observed.

Fractional distillation (without water) separates the components by boiling point. (I think the explanation in the text is not quite accurate).
Both steam distillation and fractional distillation of essential oils is much cheaper than enfleurage, but different mixtures of compounds are obtained and heat causes some rearrangements and changes in structure of the essential oil components.
Oil ylang-ylang (Cananga odorata, Annonaceae) is widely used in perfumes and is relatively expensive.

Ylang-ylang

Patchouly oil (Pogostemon cablin,Lamiaceae or Labiatae) was brought from India to England by the British East India Company.
This perfume became the mark of dissolute women. Used in heavy perfumes and soaps as a fixative. Isolated by distillation. The foliage is 2-3% oil. Now produced in the Seychelles and Indonesia.
Oil neroli (from orange blossoms) (Citrus aurantium) is isolated by distillation also. From Italy, Spain, Portugal, Provence. May.
Lavender (Lavendula officinalis) (Lamiaceae or Labiatae) also important from Provence.
Lemon grass oil (Cymbopogon citratus, Poaceae or Gramineae) is widely used as a substitute for expressed lemon oil. It is used in soaps, perfumes, food products, and in mosquito repellents. Citronella oil (Cymbopogon nardus) used to be widely used for this last purpose.
Expressed oils. This is useful for things like lemon, lime, etc. peels. For most plants however, the oils are contaminated with too many other things to make the method practical. The compounds are not changed by heat, however, and in some instances are better quality than steam distilled or fractionally distilled.
Tinctures (or alcoholic extracts) are widely used. They are cheap. They are sometimes contaminated with other undesirable products as well.

Lilac

Extraction with other solvents such as ether is also used sometimes.
Today, many perfumes are purely synthetic, but the best quality perfumes still come from plants. In laundry soap, this is probably not too critical. For good quality perfume, it's obviously more a concern.
In other cases, the plants are so inexpensive, that synthetic products are not competitive. Not only the isolation of the essential oil, but also the compounding of the perfume is complex and critical.
The balance of essential oils, fixatives, extenders, etc. is all involved. This stage is often highly empirical. Most perfume companies have a "nose" to evaluate the products.


Commercial essential oils
The most important families for essential oils are the Lamiaceae (Labiatae), Rutaceae, Geraniaceae, Apiaceae (Umbelliferae), Fabaceae (Leguminosae), Asteraceae (Compositae), Lauraceae, Myrtaceae, Poaceae (Gramineae) and a number of gymnosperms.
The major components of essential oils are terpenes, phenylpropanoids, and metabolized fatty acids. They are found in all different parts of plants and the essential oils from the different plant parts differ in composition. They often differ with stage of development as well.
Essential oils are used in:soaps, deodorants, toilet preparations, flavoring food and beverages, tobacco, antiseptics, solvents (e.g., turpentine), insecticides and insect repellents (as oil of citronella), plasticizers in plastics etc.
Most essential oils are not overly stable and must be stored carefully. Usually cold, in the dark and under nitrogen.


Eucalyptus
Lavender


Lecture slides

Back to Perfumes lecture notes


Revised February 2005

© David S. Seigler, Integrative Biology 363, Plants and Their Uses, Department of Plant Biology, 265 Morrill Hall, 505 S. Goodwin Ave., University of Illinois, Urbana, Illinois 61801, USA. 217-333-7577. seigler@life.uiuc.edu.