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• Definition, classification with examples.
• Structure and properties of triglycerides (oils and fats)
• Fatty acid classification - Based on chemical and
nutritional requirements with Examples
• Structure and functions of cholesterol in the body
• Lipoproteins - types, composition and functions in the
body
• Qualitative tests and functions of lipids
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Functions of Lipids
1. Lipids are an efficient source of energy when stored in adipose tissue.
2. Insulator – it protect internal organ of body from shock.
3. Lipid regulate membrane permeability.
4. Storage form of energy (triglycerides)
5. Structural components of bio membranes (phospholipids and cholesterol)
6. Protect internal organs by providing a cushioning effect (pads of fat)
7. They serve as source of fat soluble vitamins (Vit A, D, E, K)
Pragati K. Mahajan
Difference between Fats and Oils
Sr. no Fats Oils
1 Fats are solids or semisolids at room temperature
25°C.
Oils are liquid at room temperature.
2 Fats have a higher melting point than oils Oils have lower melting point than fats
3 Fats are stored in liver and bone marrow. Oils are stored in seeds and fruits.
4 Fats contain higher proportion of saturated fatty
acids.
Oils contain higher proportion of unsaturated
fatty acids
5 Fats have less iodine number as compared to oils
due to less proportion of unsaturation
Oils have high iodine numbers as compared to
fats due to high proportion of unsaturation.
6 Fats have high Reichert-Meissel number. Oils have low Reichert-Meissel number.
7 e.g. Butter fat, beef fat. e.g., Olive oil, Castor oil, Soyabean oil, Corn
oil.
Pragati K. Mahajan
Difference between Fats and Waxes
Sr. no Fats Waxes
1 The esters of fatty acids with alcohols are
called as fats.
The esters of fatty acids with higher
alcohol are called waxes.
2 Fats are not secretions Waxes are secretions.
3 Fats act as food reservoir. Waxes act as protective in function.
4 Fats are oxidized by atmospheric oxygen. Waxes resist oxidation by atmospheric
oxygen.
5 e.g. Butter fat, beef fat. e.g., Carnauba wax, beeswax, lanoline,
spermaceti wax.
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
• Hydrolysis
• Saponification
• Halogenation
• Rancidity
• Antioxidants
• Acid Number
• Acetyl Number
• Polenske Number
• Reichert-Meissl Number
Chemical Properties Of Fats/ Triglycerides:
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
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Pragati K. Mahajan
 Properties
• Density increases as protein content increases.
• Density decreases as lipid content increases.
• Smaller particles have higher density. Separated by electrophoresis and identified by
immunoelectrophoresis.
 There are four major classes of circulating lipoproteins, each
with its own
characteristic protein and lipid composition. They are
• Chylomicrons,
• Very low-density lipoproteins (VLDL),
• Low-density lipoproteins (LDL),
• High-density lipoproteins (HDL).
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Functions and Importance of Cholesterol
• Structural component of cell membranes and myelin sheath
• Essential component of lipoproteins
• Precursor of steroid hormones and vitamin D₃
• Regulates membrane fluidity
• Supports bone health, tissue repair, and healing
• Protects internal organs and provides insulation to nerve fibers
• Used in the pharmaceutical industry to manufacture steroid hormones and vitamin D
• Chemically forms cholesteryl esters with fatty acids and can be oxidized to cholestenone
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
Pragati K. Mahajan
METABOLIC DISORDERS OF LIPIDS
• 1. Obesity is due to accumulation of excess of body fat.
• 2. Lipidosis: Abnormal lipoproteins in blood or specific lipids in blood tissue.
• 3. Hyperlipidemia: Increase in plasma cholesterol or plasma triglycerides.
• 4. Hyperlipoprotenemia: Increase in lipoproteins.
• 5. Ketosis: Formation of ketone bodies in blood or urine due to excessive oxidation of
fatty acid.
• 6. Lipid storage diseases (Enlargement of liver and spleen, leads to mental
retardation)Niemann Pick disease Gaucher's disease Metachromatic leukodystrophy
Pragati K. Mahajan
Thank you