Fatty acid

In chemistry, especially biochemistry, a fatty acid is an organic acid (or carboxylic acid) with a long aliphatic tail (long chains), either saturated or unsaturated.

Industrially, fatty acids are produced by the hydrolysis of the ester linkages in a fat or biological oil (triglycerides), with the removal of glycerol. See oleochemicals.

Table of contents

1 Saturated 2 Unsaturated 3 Free Fatty Acids 4 pH

Saturated

Saturated fatty acids are of the form

  O
R-COH  , that is, R-COOH

where

R = CH3-(CH2)n

Saturated are:

• Butyric: CH₃(CH₂)₂COOH
• Palmitic (hexadecanoic acid): CH₃(CH₂)₁₄COOH
• Stearic: CH₃(CH₂)₁₆COOH

Unsaturated

Unsaturated fatty acids are of similar form, except that one or more alkene functional groups exist along the chain, substituting singly-bonded

-CH2-CH2-

part of the chain with doubly-bonded

 -CH=CH-  

portions (this is, with carbons attached with a double bond to another carbon). In most of these, each double bond has 3n carbon atoms after it, for some n, and are all cis bonds; they are called the omega-3 double bond, omega-6, omega-9, and so on.

• Linolenic CH₃(CH₂)₄CH=CHCH₂CH=CH(CH₂)₇COOH , is an omega-3 fatty acid.
• Arachidonicare and Linoleic are omega-6 fatty acids.
• Oleic CH₃(CH₂)₇CH=CH(CH₂)₇COOH and Erucic and oleic are omega-9.

Stearic and oleic acid are both 18 C fatty acids. They differ only in that stearic acid is saturated with H, while oleic acid is an unsaturated fatty acid (with two less H than the anterior).

Image.Several fatty acid molecules

Essential fatty acids or polyunsaturated fatty acids are fatty acids that are required in the human diet. This means they cannot be synthesized by the body and must be obtained from food. We can easily make saturated fatty acids and unsaturated fatty acids that have one double bond (monounsaturated fatty acids), but we do not have the proper enzymes to synthesis unsaturated fatty acids that have more than one double bond (polyunsaturated fatty acids).

These essential fatty acids are very important to our immune system and to help us regulate our blood pressure, for they are used to make essential compounds, such as prostaglandins.

Free Fatty Acids

Fatty acids not bound or attached to other molecules, like triglycerides, cholesterol and phospholipid.

The uncombined fatty acid or Free Fatty Acids may come from the breakdown of a triglyceride into its components (fatty acids and glycerol).

pH

Fatty acids do not have a pH. pH is a measure of acidity (or alkalinity) of an aqueous solution. Since fatty acids are insoluble in water, it is impossible to measure a fatty acid's pH.

See also : triglycerides.