gcsescience.com                                       75                                       gcsescience.com

Products from Oil

Vegetable Oils.

What are Vegetable Oils?

Vegetable oils come from many plants. Examples
are lavender, olive, palm, rapeseed and sunflower.
The oils contain a lot of energy and are used as food
(in cooking - see below, or making emulsions)
for making fuels (for example biodiesel).

How are
Vegetable Oils Extracted?

It is usually the seeds (or nuts) of a plant that contain
the most oil. The oil is extracted by crushing the seeds and
then squeezing the crushed material (called pressing).
Some oils are extracted by distillation. The oil can then be
refined (made purer) by removing water and other impurities.

Why are
Vegetable Oils used in Cooking?

Vegetable oils used in cooking have a higher boiling point
than water which boils at 100 °C. Cooking food at a
higher temperature is quicker and produces different flavours.
The cooked food usually has more energy because
some of the oil remains on the food after cooking and some of
the water in the cells of the food becomes replaced by oil.
Eating too much food cooked in oil can make you overweight.
This happens if the oily food that you eat has more energy
in it than the amount of energy that you use during exercise.

Vegetable Oils Healthy to Eat?

Some vegetable oils are better for your health than others.
Oils containing many unsaturated fats are more
healthy than oils with a large proportion of saturated fats.
Unsaturated means that the molecule contains
one or more double bonds between carbon atoms.
Saturated means that the molecule has no double bonds.
Bromine water can be used to see if a substance
such as an oil or other compound has double bonds.

Palm oil is more saturated and sunflower oil is more unsaturated.
Olive oil and rapeseed oil are somewhere in between.
It is possible to make an oil more saturated to make margarine.

back          Links          Revision Questions          next

gcsescience.com     The Periodic Table      Index      Oil Products Quiz    gcsescience.com

Home      GCSE Chemistry      GCSE Physics

Copyright © 2015 gcsescience.com. All Rights Reserved.