Hydrogenation of Lipids Flashcards
What is hydrogenation?
The removal of carbon double bonds
What affect does hydrogenation have on melting point?
Increases it because removal of the kink makes the lipid more stable
What affect does hydrogenation have on the crystal structure of lipids?
Changes it
What does hydrogenation convert liquid oils to?
Semi solid / plastic fats
How does hydrogenation affect cis bonds?
Converts them to trans bonds
What properties of lipids does hydrogenation improve?
Resistance against oxidation
Stability
What is a con of hydrogenation?
Produces trans fatty acids which have negative health affects
Describe the process of hydrogenation.
- Double bond is absorbed by the catalyst
- Hydrogen from catalyst is transferred to one of the carbon atoms of the double bond
- The other carbon binds to the catalyst
- A hydrogen replaces the catalyst, binding to the carbon
- A saturate is produced
What is the catalyst in hydrogenation?
Nickel with bonded hydrogen
Why might the hydrogenation reaction be reversed?
If the hydrogens bonded to the double bond are lost back to the catalyst
What is selective hydrogenation?
Hydrogenation of unsaturated acids with minimum formation of complete saturates
Which double bonds are hydrogenated first in selective hydrogenation?
Those which are furthest from the glycerol backbone
Which fatty acids are hydrogenated first?
Those with the most unsaturations
What are the factors affecting hydrogenation?
Temperature
Pressure
Catalyst concentration
Agitation
How can the hydrogenation of at least one, but not all, double bonds be achieved?
By changing the parameters which prevents formation of trans fatty acids
