When heated to high temperatures or exposed to air for long periods, the oils develop free fatty acids that lower the smoke point and have a bad taste.
As a result, foods cooked in an already used oil will have an unpleasant taste and will also be richer in substances harmful to our health, such as acrolein and acrylamide.
The advice is to discard the oil after having used it once or twice to fry, or to throw it away from the first use if the frying was abundant and with a sustained flame, or if it has planned breading.
Naturally, to "throw away an oil", it is intended to place it in the special containers for used oil and deliver it to the nearest collection center.
