Essential oils are one of the finest gifts of nature for humankind. For thousands of years, civilisations from Egypt to India to China has made use of essential oils, extracted in various ways from flowers, seeds, bark, resins and other parts of plants for variety of reasons including medical, culinary and perfumery. The recent revival in demand for essential oils in last half century has led many to wonder what are essential oils and how they are used? In this article, we will briefly discuss about the basics of essential oils.
Essential oils, also known and ethereal oils or volatile oils, are aromatic concentrated hydrophobic volatile liquid extracted from plants. Essential oils are extracted from flowers, leaves, stems, bark, seeds or roots of shrubs, bushes, herbs and trees. Essential oil contain the characteristic fragrance or essence of the plant from which it has been extracted.
In other words, an essential oil is the essence that is extracted from the flowers, petals, leaves, roots, bark, fruit, resins, seeds, needles, and twigs of a plant or tree.
Essential oils are found in the specialised cells or glands of plants. They are the reason behind the specific scent and flavours of spices, herbs, flowers and fruits. It is interesting to note that not all plants have these aromatic compounds. As of now, around 3000 essential oils are known, out of which around 300 are considered commercially important.
Essential oils are volatile and evaporate rapidly when exposed to air. Most of the essential oils are colourless except for few such as cinnamon essential oil which is reddish, camomile which is bluish and wormwood essential oil which is greenish in colour. Similarly, most of the essential oils are lighter than water except for few such as cinnamon essential oil, garlic essential oil and bitter almond essential oil. Essential oils are usually liquid, but can also be solid (orris) or semi-solid according to temperature (rose).
Essential oils are of complex composition and contain hundreds of unique and different chemical components including alcohols, aldehydes, ethers, esters, hydrocarbons, ketones, and phenols of the group of mono- and sesquiterpenes or phenylpropanes as well as nonvolatile lactones and waxes.
Essential oils and fatty oils are different. Fatty acids are non-volatile and non-aromatic oils processed from nuts, seeds and vegetables and are not essential to the life processes of the plant. Some examples of fatty oils are corn oil, coconut oils, olive oils, peanut oil and avocado oil. We use fatty oils on daily basis in our cooking and to moisturise skin.
Fatty oils are also called fixed oils since they maintain their liquid state even at high temperatures. In comparison, essential oils vaporize when they’re heated. Unlike essential oils, fatty oils are greasy and stain a paper permanently.
Fatty oils have large molecules and do not pass through tissues, cell walls and membranes. Fatty oils do not have any of the famous essential oils properties like antibacterial, antiviral, anti-fungal, anti-parasitic and antiseptic.
Essential oils are extracted mostly using distillation and expression. Some of the methods used are steam and/or water distillation, solvent extraction, absolute oil extraction, resin tapping, and cold pressing. The method of extraction employed depends on the quality of the material used and the type of aromatic product that is required.
Extraction of essential oils are long and expensive process. Some plant materials like flowers are subject to deterioration and are processed as soon as possible after harvesting; others, including seeds and roots, can be stored or transported for extraction later.
Essential oils are highly concentrated. A very large amount of raw material, several hundred or even thousands of pounds, is required to extract a few pound of essential oil. For example, approximately 5,000 pounds of rose petals produces one pound of rose oil, 250 pounds of lavender produces 1 pound of lavender oil and 3000 lemon produces 2 pounds of lemon oil. And this is the main reason why some essential oils are expensive.
Contrary to popular belief these days, essential oils are used not just in aromatherapy, but also in a range of everyday articles. They are used for flavouring food and drink and for adding scents to incense and household cleaning products. In fact, the main reason for the expansion of the essential oil industry in the last half century is the development of food, cosmetics, and fragrance industries.
The largest consumer of essential oils is the flavour industry. Essential oils with citrus properties – orange, lemon, grapefruit, mandarin, line – are widely by soft drink industry. In addition, alcoholic beverage industry is another major user of essential oils, for example, anise in numerous specialties of the Mediterranean region, herbal oils in liqueurs, ginger in ginger beer, and peppermint in mint liquors.
Essential oils including ginger, cinnamon, clove, and peppermint are used in confectionery, bakery, desserts, and dairy products. The spicy oils are widely consumed by in preparation of salted chips.
The fast-food and processed food industries are also substantial users of essential oils, although the main demand is for spicy and herbal flavors. Important oils here are coriander (especially popular in the United States), pepper, pimento, laurel, cardamom, ginger, basil, oregano, dill, and fennel.
Another major consumer of essential oils are the manufacturers of oral care products, mouth refreshing confectioneries, personal hygiene and cleaning industry. They use a wide variety of essential oils including eucalyptus, mint, citronella, lemongrass, herbal and fruity oils.
Last but not the least, a wide range of essential oils are nowadays are used in alternative or natural medicine with aromatherapy. Aromatherapy and natural products, where essential oils are emphasised as the natural ingredients, are a very-fast-developing segment of the industry.