Saturated fatty acids - Definition, structure & examples

Jan 2014  › › Saturated fatty acids - Definition, structure and examples
Saturated fatty acids (SFA) are long-chain carboxylic acids characterized by the presence of carboxyl group. Their structure does not contain double bonds between the individual carbon atoms.
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SFA usually contain between 3 carbon atoms (propionic) and 36 carbon atoms (hexatriacontanoic). The chain of carbon atoms has the maximum possible hydrogen atoms for its structure. In nature, many saturated FAs occur and the difference between them is the number of carbon and hydrogen atoms present in their structures.

Definition of saturated fatty acid

Saturated fatty acid definition: "a fatty acid whose carbon chain cannot absorb any more hydrogen atoms; found chiefly in animal fats" definition by wordnetweb.princeton.edu/perl/webwn.
Definition of saturated FA: " A fatty acid, such as stearic acid, whose carbon chain contains no unsaturated linkages between carbon atoms and hence cannot incorporate any more hydrogen atoms" as defined by medical-dictionary.thefreedictionary.com.

Structure of saturated fatty acid

To understand the structure of SFA, we can take the example of butyric acid. Its chemical formula is CH3CH2CH2-COOH.
1.example of chemical structure of saturated FA
The structure shows that the carbon atoms contain no double bonds between them.

2.Example flat structure of SFA
In the diagram of flat structure, the positioning of the carbons and hydrogen atoms in relation to one another is clearly seen.

3.Example of ball-and-stick model of saturated FA.
The ball and stick model shows the positioning of atoms in a long-chain SFA is well defined.

Butric or butanoic acid is present in many milk products such as milk, butter and cheese. It is also produced by anaerobic fermentation in the intestines.

Examples of saturated fatty acids and structures

Lauric acid contains 12-carbon atoms and is a carbon-chain example of SFA. It is a medium chain FA with the molecular formula C12H24O2. It is a white powdery solid. Coconut oil is a rich source. It is also present in smaller quantities in milk including breast milk. This FA has been found to increase the level of total cholesterol, particularly  high-density lipoprotein (HDL) cholesterol. Increase in HDL decreases the risk of atherosclerosis.

Myristic acid is an example of long chain SFA. It contains 14 carbon atoms in a chain. Its molecular formula is C14H28O2. Its boiling point is 250.5 °C. It acts as an anchor in biomembranes. Esters of this SFA, known as myristate have high skin absorption rate and are used in cosmetic preparations and topical medicines. Nutmeg butter is a very rich source of this SFA. It is also present in coconut oil and animal lipids. It is also found in high concentrations in sperm whale oil.

Palmitic acid is an example of long chain SFA. It contains 16 carbons in a chain. It appears as white crystals. Its molecular formula is C16H32O2 and its melting point is 62.9 °C. It is the most common SFA found in vegetable oils and animal lipids. Palm oil, palm kernel oil, and coconut oil are major plant sources of this SFA. It is also present in dairy products and meat. Its salt or ester is known as palmitate.

Stearic acid contains 36 hydrogen atoms and 18 carbon atoms in a long chain. Its an example of long chain SFA. It appears as white waxy solid with the melting point of 69.6 °C. Its molecular formula is C18H36O2. It present in both animal and plant sources of SFA. Animal lipids, cocoa butter and shea butter contain abundant quantities of this SFA. Stearates are salts and esters of this SFA.
In general, intake of saturated fatty acids is directly linked to increase in cardiovascular risks.

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Saturated fatty acids - Definition, structure and examples

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