Analysis of Edible Fats
The degree of saturation is decisive whether a fat is solid
or liquid at room temperature. Fats containing a high proportion
of unsaturated fatty acids are more liquid at room temperature
than the saturated ones and have a shorter shelf life.
Examples of fats rich in saturated fatty acids
are especially animal fats and food containing animal fats
(e.g. lard, butter, meat sausages) as well as fats from tropical
plants (coconut fat, palm fat). Some long chain saturated
fatty acids can give rise to a raised cholesterol level upon
consumption.
Long term storage of untreated oils is a problem as they
can go rancid rather quickly. The more unsaturated
fatty acid they contain, the quicker they go rancid. The primary
cause of rancidity is exposure to oxygen resulting in oxidation
of oils.
Hydrogenation is performed under high pressure
and high temperature in presence of a nickel containing catalyst.
During this hardening reaction the so called trans-fatty acids
may form which are also implicated in the build up of cholesterol.
Even traces of nickel from the catalyst remain
in the hardened fat as a contaminant. Margarine is an example
of a hydrogenated fat.
Antioxidants prevent fats and oils from
being oxidized and prolong therefore the shelf life. Edible
fats contain some natural tocopherols (vitamin E) as an antioxidant.
Legally permitted food additives acting as antioxidants are
vitamin C (ascorbic acid) or the more lipophilic ascorbylpalmitate
as well as additional vitamin E or BHT (butylated hydroxytoluene)
or BHA (butylated hydroxyanisole).
Metrohm has a variety of methods and instrumentation
for the determination of the quality of fats at hand.
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Food
Analysis 
