The determination of polar compound content in frying oils provides the most reliable measure of the extent of oxidative degradation (Arafat, 2014). In this study, the contents of the polar
fraction increased almost linearly with the frying time, at the rate affected by the frying temperature (Table 2). The total polar content during frying at 150 C was 18% and at 180 C, it was near to 23% at the end of frying time. This was still below the 25% discard level set in many European countries, including Poland (Dziennik Ustaw, 2012).