TESTO 270 BT - Page 21

7 Using the product
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may be a variation of several percentage points in the % TPM value for fresh
cooking oils, depending on the type.
The maximum service life for the cooking oil cannot be derived from this.
Example: Fresh palm oil has a higher % TPM value than other cooking oils, but
ages considerably more slowly.
Use of additives
The testo 270 BT is designed for the use of pure fats/oils. If additives are used,
deviations may occur.
Comparison of laboratory methods / testo 270 BT
Cooking oil is a mixture of substances with a wide variety of polarities. During
ageing, the proportion of more highly polar components increases. The
laboratory method of column chromatography separates the fat into a polar and
a non-polar group. The proportion of the polar group compared to the total
amount of cooking oil being investigated is described as the % TPM value (total
polar materials).
The % TPM value established by column chromatography may vary slightly
depending on the setting of the separation limit between the polar and the non-
polar group.
Depending on the type of fat, slight variations of the polarity in both groups
(polar/non-polar) may occur which are not however identified by the
chromatography.
On the other hand, the testo 270 BT records the entire polarity of the cooking oil
and thus the actual polarity of both groups (polar/non-polar). This means the
reading of the testo 270 BT may be higher or lower than that of the column
chromatography in individual cases.
An example of this is coconut oil, for which the testo 270 BT shows higher TPM
values than column chromatography. However, this fat is unsuitable for deep fat
frying and is therefore primarily used for roasting.
Free fatty acids
The testo 270 BT measures the total amount of polar materials in the cooking fat
(% TPM) which makes it very possible to evaluate the load of the oil as a result
of deep fat frying. On the other hand, free fatty acids (FFAs) are used for the
evaluation of the age of the fat during storage. FFAs are not suitable for
identifying the thermal loads of the oil. FFAs cannot be measured with the
testo 270 BT.
Polymeric triglycerides (PTGs)
Polymeric triglycerides are also being used for the evaluation of cooking oils
with increasing frequency. The results of this method are in most cases
comparable with the % TPM value.
PTG ≈ % TPM/2