Qualitative test of Lipids II.pdf, Schemes and Mind Maps of Biochemistry

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Lipids

Qualitative test of lipids (II)

Fatty Acids Classification

1. Saturated fatty acids:

 Have no double bonds ,side chain are (alkane).

 Depending on the side chain, it’s divided to:

Short Side Chain Long Side Chain

From 2 to 10 Carbon atoms,

present as liquid in room temp.

More than 10 Carbon atoms,

present in solid at room temp.

e.g. butyric acid (4C). e.g. Palmatic acid (16C).

Qualitative tests of lipids II

**1. Acrolein test.

2. Sudan IV Test.
3. Copper acetate Test.
4. Qualitative estimation of Cholesterol by Liebermann -**

Burchard Test.

5. Unsaturation Test.

nd

Sudan IV test

 Objective:

 To detect presence of lipids.

 Principle:

 Sudan IV is a non-polar stain that

readily stains lipids red-orange

 but does not stain polar compounds

or aqueous solutions

ed

Copper acetate Test

 Objective:

 To distinguish between oil or neutral fat and fatty acid

saturated and unsaturated.

 Principle:

 The copper acetate solution does not react with the oils,

 while saturated and unsaturated fatty acids react with

copper acetate to form copper salt.

 unsaturated fatty acids can only be extracted by petroleum

ether.

ed

Copper acetate Test

copper oleate in

the petroleum ether

copper acetate

Olive oil Oleic acid

copper acetate

petroleum ether

and dissolved oil

ed

Copper acetate Test

 Materials:

Olive oil , oleic acid, petroleum ether ,copper acetate solution (5%).

 Method:

 Take two test tubes put 1 / 2 g of each sample and then added 3

ml of petroleum ether and an equal volume of a solution of

copper acetate.

 Results:

Tube Observation Comments

Olive oil

Oleic acid

 Materials:

Crystals of cholesterol, Acetic anhydride, Concentrated sulfuric acid,

Chloroform.

 Method:

 Dissolve a few crystals of cholesterol in 2 ml of chloroform in a

dry test tube,

 Now add 10 drops of acetic anhydride,

 Add 2 to 3 drops of conc. sulfuric acid.

 Results:

4 th Qualitative estimation of

Cholesterol

by Liebermann - Burchard Test

Tube Observation Comments

Cholesterol

Olive Oil

th

Unsaturation test

 Objective:

 To indicates the amount of presence of double bonds in the lipid

sample.

 Principle:

 All neutral fats contain glycerides of some unsaturated fatty acids.

 These unsaturated fatty acids become saturated by taking up

iodine.

 If the fat contains more unsaturated fatty acids, it will take up

more iodine.

th

Unsaturation test

 Result:

Sample

Number of drops added from the sample

Conclusion

Mustard oil

olive oil

saturated fat

Comparing between content of fatty

acid in different type of oils:

Type of oil

Capric (Decoic) C 10

Palmitic C 16

Stearic C 18

Oleic (C 18 : 1 )

Linolenic (C 18 : 3 )

Linoleic (C 18 : 2 )

Arachidic C 20

Any special fatty acid

Coconut Oil 6. 0 - 10. 0 8. 0 - 11. 0 1. 0 - 3. 0 5. 0 - 8. 0 ---- 0 - 1. 0 0 - 0. 5 Palmitoleic tr - 2. 5

Corn (Maize) Oil 7.^0 8.^0 -^12.^0 2.^0 -^5.^0

49. 0 ----^34.^0 -^62.^0 ----^ ----

Cotton Seed Oil ----^20 2.^0 35 ----^42 ----^ ---- Mustard Seed Oil ----^1.^5 0.^4 22 6.^8 14.^2 ----^ Erucic^47.^0

Olive Oil ---- 7. 0 - 16. 0 1. 0 - 3. 0 6580 ..^00 - ---- 4. 0 - 10. 0 0. 1 - 0. 3 ----

Palm Oil ---- 32. 0 - 45. 0 2. 0 - 7. 0 3852 ..^00 - ---- 5. 0 - 11. 0 ---- ----

Safflower Oil ---- 3. 0 - 6. 0 1. 0 - 4. 0 1321 ..^00 - tr. 73. 0 - 79. 0 0. 2 ----

Sesame Oil ---- 7. 0 - 9. 0 4. 0 - 5. 0 4050 ..^00 - ---- 35. 0 - 45. 0 0. 4 - 1. 0 ----

Soya Bean Oil ----^7.^0 -^11.^0 2.^0 -^6.^0

34. 0 5.^0 -^11.^0 43.^0 -^56.^0 )^ ----^ ----

Sunflower Seed Oil ----^ ----^ ----^ ----^3.^0 -^6.^0 1.^0 -^3.^0 14.^0 -^35.^0

Behenic

1. 8 Wheat Germ Oil ----^ ----^ ----^ ----^11.^0 -^16.^0 1.^0 -^6.^0 8.^0 -^30.^0

Tocopherol

1. 3 - 0. 5