Malcolm G Stephen 2003

Fats and Oils

© Malcolm G Stephen 2004

Malcolm G Stephen 2003

Fats and Oils

Naturally occurring

Animal fat

Vegetable oil

Marine oil

lardsuet

sunflower oilcoconut oil

cod liver oilwhale oil

Malcolm G Stephen 2003

Fats and Oils

glycerol

Systematic name is propane-1,2,3-triol

Fats and oils are built from an alcohol with three -O-H groups.

Malcolm G Stephen 2003

Fats and Oils

Stearic acid

Systematic name is octadecanoic acid

The other components of fat molecules are carboxylic acidssuch as

Malcolm G Stephen 2003

Fats and Oils

Fats and oils are ESTERS of glycerol and long chain carboxylic acids

Malcolm G Stephen 2003

Fats and Oils

The structural formula shown above suggests that the fat

molecule is shaped like an E, but the molecule is actuallyshaped more like this-

Removal of water in the condensation reaction gives a fat-

Malcolm G Stephen 2003

Fats and OilsFats are mainly built from carboxylic acids with C-C single bonds.

Stearic acid in beef fat

notice that with only C-C bonds the molecule is “straight”

Malcolm G Stephen 2003

Fats and OilsOils have some C=C bonds in the carboxylic acids from which they are made.

Oleic acid in olive oil

notice that the shape of the molecule is distorted by the C=C bond

Malcolm G Stephen 2003

Fats and Oils

Oil

Fat

Double bonds in oil make the molecule less compact.Less tightly packed molecules make oils liquid.

Fat molecules pack together tightly, making fats solid at room temperature.

Malcolm G Stephen 2003

Fats and OilsConverting C=C bonds to C-C will change oils into fats.This is done by addition of hydrogen (hydrogenation) using a nickel catalyst.

in oil

in fat

Malcolm G Stephen 2003

Fats and Oils

© Malcolm G Stephen 2004