Presentation on Lipids

1. HYDROGENATION
OF
LIPIDS

2. Introduction of lipids
What is hydrogenation
What are hydrogenated fats
Trans fats
Industrial uses of lipids

3. Lipids
Lipids is an essential part of our diet and nutrition, and
we cannot live without it.
Our bodies require small amounts of “good fat” to
function and help prevent disease.

4.  The two main types of lipids are saturated and
unsaturated
Lipids
Unsaturated Lipids Saturated Lipids
Eg :Trans or Hydrogenated
fats

5. Have you heard of trans fats?
These fats are the “bad fats” found in food
that lead to higher levels of the bad
cholesterol, which can lead to heart disease.
While these can occur naturally, many are a
type of hydrogenated fat.

6.  To treat with hydrogen-is a chemical reaction between
molecular hydrogen (H2) and another compound or
element.
 The process is commonly employed to reduce or
saturate organic compounds.
 Hydrogenation typically constitutes the addition of pairs
of hydrogen atoms to a molecule , often an alkene.
What is hydrogenation ?

7.  Catalysts are required for the reaction to be usable,
non-catalytic hydrogenation takes place only at
very high temperatures.
 Hydrogenation reduces double and triple bonds in
hydrocarbons.

8. 1. The reactants are adsorbed on the catalyst
surface and H2 dissociates.
2. An H atom bonds to one C atom.The other C atom
is still attached to the surface.
3. A second C atom bonds to an H atom.The
molecule leaves the surface.
Steps in the hydrogenation

9.  Hydrogenated fats are fatty acids that have
been chemically altered.
In general, hydrogenated fats were oils whose
chemical structures were changed to become
solid fats.

10. Saturated fats do not have double bonds
between carbon atoms.
c-c-c-c-c-c-c-c-c-c-
o
o
H H H H H H H H H H
H H H H H H H H H
H

11. Unsaturated fats have double bonds between
carbon atoms.
c-c-c-c-c
c-
o
o
H
-c
H H H H H H
H H H H H

12. Unsaturated fats can undergo a chemical
reaction.
 Hydrogenation reaction, that changes their
double bonds to single bonds.
The unsaturated fat reacts with hydrogen
gas in the presence of a metal catalyst.

13. Normally,
Palladium
(Pd)
Nickel
(Ni)
Platinum
(Pt)

14. Hydrogenation reaction reduces the number of
double bonds in original fat.
If just some of the double bonds are turned in
to single bonds, this is called a Partial
hydrogenation.
If all the double bonds are turned in to a single
bond, a hydrogenated, saturated fat is formed.

15. C C C C
H
H H
H
H H
H
H
H H
H2
Nickel
Catalyst

16. When a fat is hydrogenated, the melting point
changes so the fat is now a solid at room
temperature.
The hydrogenated fat is now easy to spread
on a piece of toast.
Hydrogenated fats are found in margarine and
vegetable shortening.

18. When an unsaturated fat is hydrogenated,
sometimes double bonds can reform.
When the bond reforms, it’s in a different
configuration than the natural fats.
Natural fats have a cis double bond, meaning
the hydrogen atoms are on the same side of
the double bond.

19. An easy way to remember this is to use
alliteration: cis, same side.
C
H H
C
Cis double bonds have hydrogen atoms on the same side of the double
bond.

20.  Trans fats however, have double bonds with
the trans configuration, which means the
hydrogen atoms are on opposite sides of the
double bond.
C C
H
H
Trans double bonds
have hydrogen
atoms on the
opposite side of the
double bond.

21. Industrial Uses Of Lipids
Trans fats contents in various foods , ranked in gram per 100g
FoodType Trans fat content
Shortenings 10g to 33g
Margarine, spreads 0.2g to 26g
Butter 2g to 7g
Whole milk 0.07g to 0.1g
Breads/Cake products 0.1g to 10g
Cookies and Crackers 1g to 8g
Salty snacks 0g to 4g
Cake frostings, sweets 0.1g to 7g
Animal fats 0g to 5g
Ground beef 1g