Fats and oils Flashcards
What do fats and oils do
Provide us with energy and play an important role in the transport of vitamins which are soluble in fats around the body.
How are fats and oils obtained
From animal, marine and vegetable sources
Fats and oils are…..
Ester molecules which supply energy in the diet in a more concentrated form than carbohydrates
How are fats and oils formed
By the condensation reaction between glycerol (alcohol) and different long chain fatty acid (Carboxylic acids)
Glycerol
Aka - propane - 1,2,3 - triol
Has 3 hydroxyl functional groups
More viscous than other alcohols since it has more functional groups
Long chain fatty acid
Commonly stearic acid and oleic acid - both have 18 carbon atoms in the chain
They can be either saturated or unsaturated
Reaction equation for formation of fats and oils
Glycerol + fatty acids ——> Ester (fat/oil) + water
What controls whether fat or oil is produced
Depends in the fatty acid - whether it is saturated or unsaturated
If fatty acid is saturated what is produced
Fats
If fatty acid is unsaturated what is produced
Oils
Fats -
Formed from saturated fatty acid
Structure is even so it can be tightly packaged.
The tighter the molecules are packed the greater the London dispersion forces between the molecules.
Stronger these molecules the harder they are to break apart. - hence they are solid at room temperature
Oils -
Uneven, distorted structure means it is harder to pack the molecules closer together
Less London dispersion forces between the molecules since they are further apart.
Since these forces are less it is easier to split the molecules apart
Therefore they have a lower melting and boiling points than fats.
Hence they are liquid
What happens when oils are converted to fats
The double bond between the carbons breaks and a hydrogen is added
Hydrogenation
Conversion of oils to fats
Oils have more unsaturated bonds which can become saturated when hydrogen is added across the double bond
Increasing the level of saturation increases how closely the molecules pack together.
This increases the strength of the London dispersion forces between the molecules making it harder to break them apart - meaning the melting and boiling points increase.
Hydrolysis of fats and oils
Formation of fats is a condensation reaction
The hydrolysis of a fat or an oil would result in the formation of glycerol and the original fatty acids.
