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| Definition of Oils and Fats |
| Esters produced through the reaction between fatty acids and glycerol (propan-1,2,3-triol). |
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| The Difference between 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.
- At room temperature, fats normally exist in a solid form.
- Fats in liquid form are known as oils.
- Fats are usually found in:
- Various types of oils can be obtained from plants, such as:
- Palm oil, soybean oil and coconut oil.
- 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.
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| Example of An Esterification Reaction between Fatty Acids with Glycerol to form Fat |
- 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 as shown below:
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| Sources of Oils |
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- Mustard seeds
- Sesame seed
- Sunflower seeds
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| Difference between Oils and Fats |
| Aspect |
Oils |
Fats |
| Source |
From plants |
From animals |
| Physical state at room temperature |
Liquid |
Solid or semi-solid |
| Melting point |
Less than 20℃ |
More than 20℃ |
| Content of fatty acids |
High percentage of unsaturated fatty acids |
High percentage of saturated fatty acids |
| Example |
Palm oil |
Butter |
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| Saturated Fats and Unsaturated Fats |
- 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.
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| Saturation |
Fatty Acids |
Structural Formula |
| Saturated |
Stearic acid |
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| Palmitic acid |
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| Unsaturated |
Oleic acid |
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| Linoleic acid |
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| Unsaturated Fats |
- Made from the reaction of saturated fatty acids with glycerol.
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| Unsaturated Fats |
Fatty Acids |
Structural Formula |
| Tristearin or glyceryl tristearate |
Stearic acid |
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| Tripalmitin or glyceryl tripalmitate |
Palmitic acid |
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| Unsaturated Fats |
- Made from the reaction of unsaturated fatty acids with glycerol.
- Divided into monounsaturated fats and polyunsaturated fats.
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| Unsaturated Fatty Acids |
Fat |
Fatty Acids |
Structural Formula |
| Monounsaturated fats |
Triolein or glyceryl trioleate |
Oleic acid |
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| Polyunsaturated fats |
Trilinolein or glyceryl trilinoleate |
Linoleic acid |
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| Effect of Excessive Fats toward Health |
- 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.
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