Some plants contain pleasant smelling oils called essential oils. These oils can be extracted by steam distillation, in which steam is passed into a mixture of the crushed plant material and water. The oils, being volatile, will vaporise and can be collected together with water. in the distillate. The proportion of oil in plant material is usually small, about 1-2%. Thus, a large amount of plant material is needed to obtain a small yield of the oil. Fresh orange peel gives about 2,2% orange oil which consists mainly limomene
Other citrus fruits which give essential oils include lemons and grapefruit. Oil of lemon contain mainly limomene and small percentage of citral
Essential oils can also be extracted from nutmegs, cloves, eucalyptus leaves, lemon grass and rose petals.
Essential oils are the building blocks of the fragrance and flavors industries. A unique flavors created by combining the naturally plants.
A blend of these concentrated oils, used in very small amount (less than 1%) =, will impact a characteristic and recognizable flavor to the end product. For example, the beverage industry relies heavily on the essential oils to give their fruity flavor (eg. strawberry, apple, durian, mango flavor). Essential oils are also used to give flavors to confectionery product, sweets, candies and chocolates
Petroleum ether is very inflammable and its fumes are poisonous. Conduct the evaporation of petroleum ether in a well ventilated place (preferably fume cupboard). Do not heat the ether directly over at flame
- Dice about 500 grams of orange peel using a food blender
- Pulp the peel with a mortar and pestle and put it into a 1 liter flask containing some boiling chips
- Add water to just cover the pulp . Soak overnight
- Set up the apparatus as shown below. Add boiling chips to the steam generator and the 1 liter flask
5. Heat the steam generator and pass steam into the flask until about 250 cm3 of distillate is obtained
6. Extract the oil from distillate with about 10 cm3 petroleum ether in separating funnel
7. Run off the lower aqueous layer and extract this layer again with 10 cm3 petroleum ether
8. Combine the ether extracts and evaporate the petroleum ether on an electric heater in a fume cupboard
9. What is the smell of the oily extract
- Compare the odor of the oil with that of the freshly crushed material. Do they smell the same. Sometimes, the smells differ because of the decomposition of the less stable oils during heating
- Extract essential oils from lemon peels, grapefruit peels, nutmeg seeds, coarsely crushed cloves, apricot seeds, lemon grass, eucalyptus leaves, cinnamon, anise, cumin, coriander seeds, ginger and banana peelings. Compare the odors of the various oils that have been extracted. Essential oils from such spices are often used to flavor meat products
3. Extract essential oil from flowers like roses, jasmine and pot-pourri of other flower petals. (dried or fresh). Can you make your own fragrance by blending these essential oils together?.
To make perfume, dilute one part of the blended essential oils with four parts ethyl alcohol.
To make toilet water, the ratio is 1 part oil to 10 parts ethyl alcohol
To make cologne, dilute one part oil with 20 part ethyl alcohol