This document provides information about lipids including their definition, classification, and functions. It begins by defining lipids as naturally occurring organic and water-insoluble substances that are soluble in non-polar solvents. It then classifies lipids into simple lipids like triglycerides and waxes, and compound lipids like phospholipids, glycolipids, and lipoproteins. The document discusses the biological importance of lipids, listing functions like serving as an energy source, forming membranes, and absorbing fat-soluble vitamins. It also summarizes several tests used to characterize fats and oils, including iodine number, saponification number, and acid number.

1. Have a great day to all
LIPIDS

2. Def:
- Lipids are naturally occurring organic, water insoluble substances
- Soluble in non polar organic solvents (chloroform, alcohol, ether,
benzene etc).

3. Energy source
9.5kcal/gm of TG
Membrane
Structural &
integrity
(Phospholipids &
Cholesterol)
Absorption of
fat soluble vit
Vit- A, D, E & K
BIOLOGICAL
IMPORTANCE OF
LIPIDS
Emulsifying agent
Bile salts
Endocrine function
Steroid, sex hormones & vitamin-D
LIPIDS

4. Other functions
Participates on ETC (phospholipids)
Improve taste & palatability of food
Cellular metabolic regulators (Prostaglands & steroids).
Stored around internal organs (Padding & protects )
It acts as a surfactant
Shape & Smooth appearance of the body

5. CLASSIFICATION

6.  BLOOR classification:

7. SIMPLE LIPIDS
Neutral fats
eg: Triglycerides
Waxes
R-OH + HOOC-R’ R-O-CO-R’ + H2O
alcohol acid ester

8. Neutral fats (Triglycerides)
 Esters of fatty acids with alcohol glycerol,
 A fat in liquid state is called oil
e.g: vegetable oils – Sun flower oil
Ground nut oil
Mustard oil
Corn oil, etc.

9. B) Waxes:
• Esters of FAs with higher molecular weight monohydric long chain
alcohols.
Example:
Lanolin obtained from lamb’s wool &Bees wax
• Used in pharmaceuticals as Cosmetic, Lotions, Ointments & polishes.

10. COMPOUND LIPIDS
Phospholipids Glycolipids Lipoproteins

11. PHOSPHOLIPIDS
• Esters of fatty acids containing phosphoric acid, nitrogenous bases
and other substitution groups.
G
L
Y
C
E
R
O
L
FATTY ACID
FATTY ACID
Phosphate Nitrogenous Base

12. G
L
Y
C
E
R
O
P
H
O
S
P
H
O
L
I
P
I
D
S
Phosphatidyl Choline (Lecithin)
Phosphatidyl Ethanolamine
(Cephalin)
Phosphatidyl inositol
Phosphatidyl serine
Plasmalogens
Phosphatidylglycerol (Cardiolipin)
S
P
H
I
N
G
O
P
H
O
S
P
H
O
L
I
P
I
D
S
Sphingomyelins
Phospholipids
It may be classified into 2
types based on the type of
nitrogenous base & alcohol

13. GLYCOLIPIDS / GLYCOSPINGOLIPIDS
• Lipids containing FAs, alcohol-sphingosine & additional residue are
carbohydrates with nitrogen base without phosphorous group.
Eg: Cerebrosides,
Globosides &
Gangliosides

14. LIPOPROTEINS
 Combination of lipids with a protein as prosthetic group
eg: Serum lipoproteins

15. III. DERIVED LIPIDS:
 Lipids obtained after hydrolysis of the simple and complex lipids
which possess characteristics of lipids.
 Fatty acids
 Steroids
Steroids:
Simple straight chain alcohol - glycerol
Complex cyclic alcohols - cholesterol.

16. SIMPLE LIPIDS

17. Triglycerides (Triacylglycerols)
 TG is a storage lipid in animal.
 Stored in cytoplasm of adipose cells.
 Fat stored under the skin serve as an insulator against cold
 the skin serve as an energy store and as insulator against cold
18

18. Depending upon the fatty acid residues in glycerol,
- simple triglycerides
- mixed triglycerides
E.g. Olive oil, the fatty acid is oleic
acid then it was named as triolein.
In Human fat, mixed triglycerides

19. Properties
of
Triglycerides

20. Hydrolysis
During digestion of fat in the GI tract .
21

21. Saponification
 Hydrolysis of TGs by alkali to produce glycerol & alkali salts of the FAs.
TGs + 3 KOH Glycerol + 3 R- COOK (soaps)
• Soaps are good cleaning agents, germicides & detoxicants

22. Hydrogenation (Chemical Process)
 To add more ‘H’atoms to natural unsaturated fats to decrease the number
of double bonds, to form saturated fats.
 Used to convert liquid fats of plant origin to solid cooking fats
eg: Vanaspati (dalda) – obtained from vegetable oils

23. Rancidity
 The unpleasant smell and taste, developed by natural fats upon prolonged storing.
 Caused by exposed to light, O2 & bacteria
 Due to hydrolysis or oxidation of fat
• When a fat is exposed to air, its unsaturated FAs are converted into hydroperoxides.
• Break down into volatile aldehydes, esters, alcohols & hydrocarbons
leads to disagreeable odor.

24. - Unsaturated fats are more susceptible to oxidative rancidity than
saturated fatty acids.
Lipid Peroxidation:
- Lipids undergo oxidation to produce lipid peroxides & other free
radicals, which can damage the tissues.
- To cause inflammatory diseases, ageing, atherosclerosis & cancer.

25. Antioxidants
The substances, which can prevent the occurrence of oxidative rancidity.
- Naturally occurring antioxidants
- Vitamin-C
- Vitamin-E (Tocopherol)
- Pro vit-A (β-carotene)
- Food additives such as – Propyl gallate
- Butylated hydroxy anisole (BHA)
- Butylated hydroxy toluene ( BHT)

26. Self learning topic
“CHARACTERISATI
ON
OF
FATS & OILS”

27.  Adulteration of fats & oils is increasing day by day.
 Several tests are employed in the laboratory to check the purity of fats &
oils.
• Iodine number
• Saponofication number
• Reichert-Meissl (RM) number
• Acid number

28. IODINE NUMBER
• The no of grams of iodine absorbed by 100g of fat.
• Iodine number is directly proportional to the content of USFA.
• It is used to assess the degree of USFA of fat or oils and also to check the purity &
nutritive value of fats & oils
Butter 25- 28
human fat 65- 70
Ground nut oil 85- 100

29. SAPONIFICATION NUMBER
• Number of mgs of KOH required to saponify one gram of fat or oil.
• It measure the average mol wt & chain length of the FAs present
• Saponification number is inversely proportional to Fat or Oil
Human fat 195-200
Butter 210-240
Coconut oil 250-260

30. Reichert Meissl Number (RM NUMBER)
• The number of ml of 0.1N KOH required to completely neutralize the
soluble volatile fatty acids distilled from 5g of fat or oil.
• To assess the purity of fats having more volatile fatty acids
• RM number of Butter b/w 25-30

31. Acid Number
• mg of KOH required to completely neutralize free fatty acids present
in 1gm of fat or oil.
• It indicates the degree of rancidity of fats and oils.

32. Don’t compare yourself
with anyone in this world……
If you do so,
you are insulting yourself.
Next class ppt- 03:Compound lipids & it’s functions