Download - Fats
Chapter 2: Carbon Compounds
H. FATS
What is fats & oils?
FATS:
An ester that is formed from 1 molecule
of glycerol and 3 molecules of fatty acids.
Can exist in both solid and liquid state –
in liquid state is known as OIL.
Fats & oils are chemically very similar but
difference in their physical states.
Differences between fats & oils
Fats Oils
Fats are solid at room
temperature
Oils are liquid at room
temperature
Found in animal (cow &
goat)
Found in plant
e.g: soybean, sunflower,
peanuts, olive & palm oil
fruit
Melting point: more than
20 °C
Melting point: less than
20 °C
Saturated compounds Unsaturated compounds
Importance of fats & oils
1. Source of energy
Important source energy for living things
2. Source of nutrients
The absorption of fat-soluble vitamin A,
D, E and K
3. Structural role
Needed to build membranes of all cells
4. Thermal insulation
Layer of fat – protect our body from
cold & internal organs from freezing
5. Protection
Fat protect vital internal organs in our
body
Uses of fats & oils
Cooking
Food manufacture
Cosmetic
Candle (fats from animal)
Soap making (vegetable oil are often used)
Structural formulae
Mixture of different esters derived from
variety of long-chain carboxylic acid
(fatty acids) with the alcohol,
propane-1,2,3-triol (glycerol).
Fatty acids: Long straight-chain carboxylic
acids containing between 10-20 carbon
atoms per molecule.
Fatty
acidFormula
Myristic
acidCH3 – (CH2)12 − COOH
Palmitic
acidCH3 – (CH2)14 − COOH
Stearic
acidCH3 – (CH2)16 − COOH
Lauric
acidCH3 – (CH2)10 − COOH
Oleic
acidCH3 – (CH2)7 – CH = CH – (CH2)7 − COOH
Linoleic
acidCH3 – (CH2)4 – CH = CH – CH2 – CH = CH − (CH2)7 − COOH
Linolenic
acidCH3 – (CH2 – CH = CH – CH2 – CH = CH – CH2 – CH = CH − (CH2)7 − COOH
Formation of fats
By condensation of fatty acids and
glycerol
1 molecule glycerol combines with 3
molecules of fatty acids
Name of reaction: Esterification
R1COOH
R2COOH
R3COOH
CH2 OH
CH2 OH
CH2 OH
+
3H2O
Fatty acid Glycerol
Fat/Oil
+
C O C R1
O
C O C R2
O
C O C R3
O
H
H
H
H
H
Try this:
Draw the structural formula for reaction
between palmitic acid with glycerol to form
a certain fat.
Saturated & unsaturated fats
Compare and contrast between saturated
and unsaturated fats
Converting unsaturated fats to
saturated fats Name of process:
Hydrogenation
Unsaturated fats (alkenes) from
vegetable oils such as palm oil can be
converted to saturated fats (margerine)
Example:
Name of reaction: Manufacture of
margerine
Condition:
(i) Catalyst: nikel/platinum
(ii) Temperature: 180 °C
(iii) Pressure: 4 atmospheres
Procedures:
Hydrogen gas is passed through the
unsaturated fats at 180 °C with small
amount of nikel/platinum
Effects of eating food high in fats on
health Cholesterol from fats can deposit on awll
of arteries. The wall of arteries will
harden. This cause arteriosclerosis.
Cholestrol can block the flow of blood in
the arteries
Also causing obesity, high blood pressure,
heart attacks
Industrial extraction of palm
Process
Sterilisation Stripper Digestor
Pressing
ClarificationPurificationVacuum drying
Use of palm oil
To make cooking oil and margerine
Better than the other oil such as coconut
oil (palm oil is unexpensive)
Cholestrol free thus reducing the risk of
heart disease