1. lipids fixed oils and waxes
PH103.9

2. Recap In the last class you learnt about Alkaloids Tests for alkaloids
Types of alkaloids
PH103.9

3. On completion of this period, you would be able to know
Objectives
On completion of this period, you would be able to know
Lipids
Fixed Oils
Fats
waxes
PH103.9

4. Fixed Oils, Fats & Waxes These can be obtained from plants or animals
Fixed oils are liquids at normal temperature
Fats are solids or semisolids
Chemically fixed oils and fats are esters of fatty acids with glycerol known as glycerides
PH103.9

5. Fixed Oils, Fats & Waxes Fats usually contain mixed glycerides
Usually contain saturated fatty acids like Stearic acid, Palmitic acid, Unsaturated fatty acids like Oleic acid, Linoleic acid
The oils of have more amount of Unsaturated acids where as fats comprise of Larger amount of saturated fatty acids
PH103.9

6. Fixed Oils, Fats & Waxes Fixed oils and fats can be easily hydrolysed
with aqueous sodium hydroxide
On hydrolysis we get sodium salts of fatty acids (Soap) and glycerol, this process is known as Saponification
They are insoluble in water
Sparingly soluble in cold alcohol
Soluble in Benzene, Chloroform and Ether
PH103.9

7. Fixed Oils, Fats & Waxes Fixed oils and fats cannot be distilled
If try to do as they get decomposed
Due to production of acrolein an aldehyde
If stored for longer period Fixed oils and fats become rancid by having bad taste and unpleasant odour
PH103.9

8. Fixed oils Classified into Drying oils Linseed oil
Semi drying oils Cotton seed oil
Non drying oils Olive oil
PH103.9

9. Fats Cocoa Butter Cocoa beans Lanolin or Hydrous Wool fat Sheep
PH103.9

10. Fatty acids Structural formula
Butyric acid CH3 [CH2]2 COOH
Caproic Acid CH3 [CH2]4 COOH
Caprilic Acid CH3 [CH2]6 COOH
Capric Acid CH3 [CH2]8 COOH
PH103.9

11. Fatty acids Structural formula
Lauric Acid CH3 [CH2]10 COOH
Myristic Acid CH3 [CH2]12 COOH
Palmitic Acid CH3 [CH2]14 COOH
Stearic Acid CH3 [CH2]16 COOH
Arachidic Acid CH3 [CH2]18 COOH
PH103.9

12. Waxes The physical properties of waxes are almost similar to fats
They too are esters like oils and fats
But in waxes alcohol involved is not glycerol
But a high molecular weight straight chain
monohydroxy alcohol like cetyl alcohol
PH103.9

13. Waxes Fatty acids are also high molecular weight saturated fatty acids
Waxes can be saponified only with alcoholic potassium hydroxide
Like fats they are insoluble in water
Soluble in organic solvents
Ex. Bees wax and spermaceti
PH103.9

14. Adulteration in oils Fats and Waxes
To ascertain its purity physical or chemical test are to be carried by comparing with analytical constants
PH103.9

15. Adulteration in oils Fats and Waxes
Saponification value
This value is normally applied for butterfat and denotes total amount of fatty acids present
Iodine value
Iodine value is a measure of the extent of unsaturation
Acid value
Denotes amount of free fatty acids present
PH103.9

16. Summary In this class we learnt about Lipids Fixed Oils Fats Waxes
PH103.9

17. Quiz 1. Acid value is the measure of Rancidity Peroxidation
Unsaturation
All the above
PH103.9

18. Quiz 2.Iodine value is the measure of Peroxidation Hydrogenation
Unsaturation
None of the above
PH103.9

19. Frequently Asked Questions
What are the classes of oils or lipids?
What are fixed oils? Give examples and sources of them?
PH103.9