Determination of polar compounds in abused oils and
fats is a well-accepted method due to its accuracy and
reproducibility. It provides the most reliable measure of
the extent of deterioration in frying oils and fats in most situations
(Fritsch, 1981). The level of polar compounds is a
good indicator of the quality of used frying oils and fats,
giving information of the total amount of newly formed
compounds having higher polarity than that of triacylglycerols.
Table 5 shows the changes in the percentTPCduring the
frying period.TPCwas found to increase with the frying time
for all the oils. The rate of increase was gradual forMoOand
PO and has a value of 20.78% and 21.23%, respectively at the
end of the frying period. TPC in CLO and SBO (28.73% and
31.82%, respectively) were significantly (P < 0.05) higher
than those of MoO and PO. A level of 24%total polar materials
has been suggested as the limit beyond which frying oil
should be discarded (Anonymous, 2000).