After frying at three different temperatures of 150, 200 and
250 C, TFAs in frying oils were analyzed and compared. A
progressive decrease in the content of both (cis) linoleic and (cis)
linolenic acids was observed throughout the frying period
(Table 3). The content of (cis) linoleic acid was reduced by 10.99%
and 16.21% after frying for 8 h at 150 and 250 C, respectively. The
deterioration of (cis) linolenic acid was more pronounced, with its
contents being decreased by 20.86% and 62.58%, respectively.
Aladedunye and Przybylski (2009) reported decreases of 13.3% in
linoleic acid and 47.1% in linolenic acid when fresh canola oil was
heated at 215 C for 7 days.