Key area: Fragrances Overview In this section, learn about the chemistry of terpenes and essential oils, key components of fragrances.

Essential oils are concentrated extracts of the volatile, non-water soluble aroma compounds from plants. They are widely used in perfumes, cosmetic products, cleaning products and as flavourings in foods. Terpenes are key components in most essential oils. Terpenes are components in a wide variety of fruit and floral flavours and aromas. After completing this lesson you should be able to :

Essential oils Essential oils are the concentrated extracts of volatile, non-water-soluble aroma compounds from plants. Essential oils are widely used in perfumes, cosmetic products, cleaning products and as flavourings in foods. COPY

Essential oils Essential oils are mixtures of organic compounds. Terpenes are the key components in most essential oils. COPY

The history of essential oils The benefits of essential oils have been recognised for thousands of years. Their use is described in the New Testament of the Bible. They were used in anointing rituals and in healing the sick. COPY

The history of essential oils The ancient Egyptians used essential oils for embalming, religious rites and medicinal purposes. King Tut’s tomb was found to contain 50 jars of essential oil when it was opened in COPY

Modern uses Essential oils Cosmetics Flavours Perfumes Medical Cleaning Insect repellents Dentistry Adhesives COPY

What are essential oils? ‘Essential’ refers to the fact that the oil carries the distinctive essence (scent) of the plant. Concentrated, volatile, non-water soluble aroma compounds extracted from plants. Contain no artificial substances, unlike perfumes and fragrance oils. COPY

Essential oils – composition Essential oils are mixtures of organic compounds. Terpenes are the key components of all essential oils. COPY

Essential oils – chemistry The distinctive character of an essential oil can be attributed to the functional group present in its key molecule. Esters, aldehydes, ketones and alcohols are all found in essential oils. COPY

Essential oils – perfume The ester linalyl acetate is found in the essential oil lavender. This ester is often added to perfumes. COPY

Essential oils – cleaning The essential oil known as lemon oil contains the terpene d-limonene. It is known for its ability to act as a natural solvent and a cleanser. COPY

Hospital Cleaners Certain essential oils kill bacteria and fungi (including MRSA and E. coli) within 2 minutes of contact. Essential oils are blended into soaps and shampoos used in hospitals to eradicate deadly ‘super bugs’. COPY

Essential oils – cosmetics The essential oil geraniol is added to some cosmetics to balance and revitalise the skin. COPY

Essential oil – cold sores Melissa oil contains the terpene citral, which is used to combat cold sores. COPY

Essential oils – toothpaste The essential oil thymol has antiseptic properties. COPY

Steam distillation Steam distillation is one of the methods used to extract essential oils from plants. Steam passes over the plant and extracts the essential oil. The mixture evaporates and passes into the condenser. The essential oil vapour is chilled and collected. COPY

Steam distillation COPY

Steam distillation

Essential oils – summary Concentrated extracts of volatile, non-water- soluble aroma compounds from plants. Widely used in perfumes, cosmetics, cleaning products and flavourings. Mixtures of organic compounds. Terpenes are the key components of most essential oils. COPY