Lipids and Their Classification, Study notes of Pharmacy

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Assistant Lecturer. Zuhair A. ALrawi

College of Pharmacy

third level

practical lab.(5) (Lipids)

The most important functions of lipids

 energy source.

 Provides the body with essential fatty acids necessary for growth.

 Protecting the internal organs in the body such as the heart, kidneys, and spleen. keeping them from shocks.

 A source of fat-soluble vitamins (A, D, E, and K ).

 It enters into the cell structure , especially the cell membrane.

 The fat is classified into:-

( Simple Lipids) (compound Lipids)

1- Simple Lipids : They are esters produced from the reaction of fatty acids with alcohols.

 include:-

 Fat and Oil: It is the most common fats in nature. These are glycerol esters (triple alcohol). Hydroxyl (with monohydroxy fatty acids.

 Waxes: Such as bees wax , which are esters of long- chain fatty acids with alcohols Monohydroxylate.

Classification of Lipids

1- Copper Acetate Test

This test is used to distinguish between

saturated and unsaturated fatty acids and

Triglycerides.

Experiments

1- Copper Acetate Test

• Principle:

This experiment is based on the fact that free saturated fatty acids combine with copper acetate to form Copper salts In the lower water layer is Bluish green copper precipitate. While unsaturated fatty acids give green copper salts in the upper layer of petroleum ether.

Experiments

1- Copper Acetate Test

Method:

 If the ethereal upper layer appears green and the aqueous lower layer appears blue , the fat is unsaturated fatty acid.

 If the upper layer remained clear and without color with the appearance of a greenish blue precipitate in the lower layer , the fat was saturated fatty acid.

Experiments

Experiments

Copper Acetate Test

unsaturated fatty acid saturated fatty acid

The ether layer is dissolved in the oil

the upper layer remained clear and without color

copper acetate (CH3COO)2Cus

2- Salkowiski’s reaction:

Method:

 put in test tube, 2 ml of a chloroform cholesterol solution + 2 ml of slowly concentrated H2SO4 along the side of the test tube.  Shake the tube well, then leave it until the mixture settles.  We will notice the formation of two colored layers , the upper layer which is the red chloroform layer , and the lower the acid layer and it is yellow.  Indicates the presence of cholesterol.

Experiments

Experiments

red chloroform layer

yellow layer concentrated sulfuric acid (H2SO4)

Salkowiski’s reaction

3- Rancidity Test:

Method:-

 put in test tube, 2ml of NaOH + 3 drops of α-naphthol.

 Add 2 ml of fat or any oil, then shake the mixture well.

 If rancidity is present, it gives a red or pinkish color.

 If the color appears clear, watery, there is no rancidity.

Experiments

Experiments

red or pinkish color

Rancidity Test

appears clear, watery

No rancidity Rancidity