Plant Oils

Noadswood Science, 2011

Plant OilsPlant Oils To know how plants make oils, and how these are extracted

Friday, April 21, 2023

AnagramsAnagrams Try and solve the following

anagrams: -

Nkalea Eatatsdur Iilsttioladn Onoremm Plmeroy Uredaanstut Eostningethormf Droanbroych Nkgricca

Alkane

Saturated

Distillation

Monomer

Polymer

Unsaturated

Thermosoftening

Hydrocarbon

Cracking

Plant OilPlant Oil What are vegetable oils?

Vegetable oils are natural oils found in seeds, nuts and some fruit

The plant materials are crushed and pressed to squeeze the oil out (e.g. olive oil is obtained this way)

Sometimes the oil is more difficult to extract and has to be dissolved in a solvent – once the oil is dissolved, the solvent is removed by distillation, and impurities such as water are also removed, to leave pure vegetable oil (e.g. sunflower oil is obtained in this way)

ExtractionExtraction Plant oil extraction is relatively simple, involving two

steps: - Crush the plant Remove the oil by pressing or via distillation

Or

Orange Peel Orange Peel DistillationDistillation

Watch the demo of the orange peel distillation…

Plant OilPlant Oil Molecules of vegetable oils consist of glycerol and fatty acids:

- Glycerol has three carbon atoms Fatty acids have long chains of carbon atoms

Three long chains of carbon atoms are attached to a glycerol molecule (with its three carbon atoms) – together they combine to make one molecule of vegetable oil…

Fatty AcidsFatty Acids Thee long fatty acid chains stop vegetable oils dissolving

in water

The fatty acids in some vegetable oils are saturated, and only have single bonds between their carbon atoms

Saturated oils tend to be solid at room temperature, and are sometimes called vegetable fats instead of oils

Lard is an example of a saturated oil

Fatty AcidsFatty Acids The fatty acids in some vegetable oils are unsaturated,

and have double bonds between some of their carbon atoms

Unsaturated oils tend to be liquid at room temperature, and are useful for frying food

They can be divided into two categories: - Monounsaturated fats have one double bond in each

fatty acid Polyunsaturated fats have many double bonds

UnsaturationUnsaturation The carbon-carbon double bonds in unsaturated oils can be

detected using the elements bromine or iodine – these elements react with the double bonds in the oils, and the more double bonds there are, the more bromine or iodine is used up

Unsaturated fats can be tested for using a simple test with bromine water – bromine water is a dilute solution of bromine, which is normally orange-brown in colour which becomes colourless when shaken with an alkene, or with unsaturated fats

When shaken with alkanes or saturated fats, its colour remains the same

UnsaturationUnsaturation