The N-Value gives the percentage of fat which is solid or in the
crystallised form at a given temperature:
N20= 35 indicates that 35% of the fat is in crystallised form at
20°C (the amount of solids at that temperature)
These values are measured with NMR-equipment (after heating to 60°C,
stored for one hour at 0°C and half hour at measuring temperature).
These values are not always the same as the SFC-values (solid fats
content) as used in the USA and measured on a different way.
Water is fully crystallising at 0°C (one type of molecule:
H2O). But fat, consisting of a mixture of different triglycerides,
has a melting or crystallising range. The lower the temperature
the more triglycerides are crystallised and so the larger the part
of the fat in the solid form.
The N-line is a line indicating the solids as function of temperature;
usually a few N-values are used: N10, N20, N30 and N35. Examples
are given in other pages.
A few types of melting points are used in the literature:
- The Slip melting point: in practice the temperature where only
a few percent of the fat is in the solids form. Practically this
melting point can be derived from the N-line (the melting point
is the temperature where 3-5% solids are present).
- The Wiley melting point, mainly used in the USA; gives a few
degrees higher temperature than the slip melting point.
More detailed information can be obtained from standard handbooks
Different types of fatty acids are present in the triglycerides
- Safa = saturated fatty acids, e.g. C16.0 or C18.0, but also
C12.0 (lauric acid)
- Mufa = mono unsaturated fatty acids; with one “double
bound”, like C18.1:
- Cis form = the natural form of unsaturation
- Trans form = the form obtained by the hardening process.
This trans form is also present in animal fats on a level of about
- Pufa = poly unsaturated fatty acids; with more “double
bounds”, like C18.2 or C18.3
Triglycerides or triacylglycerols
The oils and fats consist of a chemical combination of glycerol
with 3 fatty acid chains: triglycerides or triacylglycerols.
The type of fatty acids on the glycerol molecule (so the composition
of the triglycerides) determines the crystallisation behaviour of
fats and so the N-line.
Each fat or modified oil/fat consists of a large variety of triglycerides;
this results therefore in melting or crystallisation range (actually
Palmoil is a fat with a rather simple composition
of triglycerides; the main ones are:
- Trisaturated triglycerides, with 3 saturated fatty acids (mainly
palmitic=C16.0). The melting of this type of triglycerides is
about 60°C. But because there is only about 10% present, the
melting point of palm oil is about 38°C
- Disaturated-monounsaturated triglycerides (mainly consisting
of palmitic and oleic acid). The melting point of this type of
triglycerides is about 35°C.
About 45% of this type is present.
- Monosaturated-diunsaturated triglycerides (also mainly consisting
of palmitic and oleic acid). The melting of these triglycerides
is lower than the ones before; around 10-15°C
- Triunsaturated triglycerides (mainly consisting of oleic and
The melting point is even below 0°C.
Soybean oil consist of this type of triglycerides for a high percentage
and does not show crystals, when it is stored in the refrigerator
If Palmoil is partially hardened then a little bit more of the
first group is formed and, because a large percentage of the oleic
fatty acid (cis form) is transformed in elaidic fatty acid (trans
form), the second group will be at least for 50% palmitic-elaidic-palmitic
triglyceride with a higher melting point than palmitic-oleic-palmitic
triglyceride and so more in crystallised form at 20-35°C.
Simplified fatty acids and triglycerides
In literature and patents simplified fatty acids and triglycerides
are used, in which the large number of fatty acids and triglycerides
are grouped in order to be able to discuss easier the effects on
crystallisation and hardness: click for details.
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