Why should rapeseed oil not be heated?
Cold-pressed rapeseed oil starts to decompose at a temperature of about 140 °C. However, when frying and deep-frying, these are at least 160 °C. For this reason, you should not use the native fat for this purpose.
Refined rapeseed oil, on the other hand, can withstand much higher temperatures, which is why you can heat it without hesitation.