Oils and Fats

Oils and fats are parts of the dietary requirements for humans that are responsible for supplying energy, providing body temperature insulation and helping with the absorption of important vitamins.

Definition of oils and fats

Esters produced through the reaction between fatty acids and glycerol (propan-1,2,3-triol)

Fatty acids have very long carbon chains.
The characteristics of oils or fats rely on the types of fatty acids involved in the esterification reactions with glycerol.
Examples of fatty acids are palmitic acid, stearic acid and linoleic acid.

Esterification reaction

The reaction between one glycerol molecule and three fatty acid molecules forms one fat molecule.
\(R_1\), \(R_2\) and \(R_3\) represent the parts of hydrocarbon chains in fatty acids and fats.
\(R_1\), \(R_2\) and \(R_3\) can either be identical or different.

Oils	Fats
Source
Plants	Animals
Physical state at room temperature
Liquid	Solid
Melting point
Low	High
Content of fatty acids
High percentage of unsaturated fatty acids	High percentage of saturated fatty acids
Example
Palm oil	Butter

Saturated fats contain saturated fatty acids, and unsaturated fats contain unsaturated fatty acids.
Unsaturated fatty acids have at least one double bond in the carbon chain; whereas saturated fatty acids only have a single covalent bond in the carbon chain.
The presence of double bonds causes unsaturated fats to have low melting points and exist as liquids.

Examples of saturated fatty acids	Molecular formula
Palmitic acid	\(CH_{3}(CH_{2})_{14}COOH\)
Lauric acid	\(CH_{3}(CH_{2})_{10}COOH\)
Stearic acid	\(CH_{3}(CH_{2})_{16}COOH\)

Saturated fat	Fatty acid	Structural formula
Tristearin or glyceryl tristearate	Stearic acid
Tripalmitin or glyceryl tripalmitate	Palmitic acid

Examples of unsaturated fatty acids	Molecular formula
Oleic acid
Linoleic acid
Linolenic acid

Fat	Fatty acid	Structural formula
Triolein or glyceryl trioleate	Oleic acid
Trilinolein or glyceryl trilinoleate	Linoleic acid

Oils consist of a high percentage of unsaturated fats.
Unsaturated fats are converted into saturated fats through hydrogenation reaction.
During a hydrogenation reaction, hydrogen gas, \(H_2\) is passed into hot oil with the presence of nickel, Ni as the catalyst.
The double bond in the carbon chain is “opened” and the hydrogen atoms, H are added to the carbon chain.
The addition of hydrogen atoms to the carbon chain causes the molecular mass to increase that leads to the increase in the melting point and boiling point.
This situation explains why margarine exists in a solid form at room temperature, even though it is produced from oil.

Hydrogenation reaction of unsaturated fat to saturated fat

Industry	Uses
Biofuel	Oils and fats can be used to produce biofuels, such as biodiesel to be used by vehicles with diesel engines.
Nutritional source	Oils and fats supply energy and help the body to absorb important vitamins, such as vitamins A, D, E, and K.
Soap and personal care	Oils and fats are the main ingredients for soap making. Personal care items, like skin moisturisers, also utilise oils in their productions.
Animal feeds	Oils and fats are also used to manufacture feeds for cattle to fulfil their nutritional needs.

Excessive fat is dangerous.
A high correlation between a diet rich in saturated fats with cardiovascular diseases.
- Increasing cholesterol level in the body.
- Cholesterol can make blood vessel harder and narrower.
- Formation of plague and blocking blood flow.
- High blood pressure, heart attack and stroke.