structural:scholar_edition, information:extraction, structural:summarization
Cooking with oil

Heating, as well as heating vessels rapidly change characteristics of cooking oil. Oils that are healthy at room temperature can become unhealthy when heated above certain temperatures, especially when heating repeatedly. The toxic risk is linked to oxidation of fatty acids and fatty acids with higher levels of unsaturation are oxidized more rapidly during heating in air. So, when choosing a cooking oil, it is important to match the oil's heat tolerance with the temperature which will be used. and to change frying oil a few times per week. Deep-fat frying temperatures are commonly in the range of 170–190 °C (338–374 °F), less commonly, lower temperatures ≥ 130 °C (266 °F) are used.

Palm oil contains more saturated fats than canola oil, corn oil, linseed oil, soybean oil, safflower oil, and sunflower oil. Therefore, palm oil can withstand deep frying at higher temperatures and is resistant to oxidation compared to high-polyunsaturated vegetable oils. Since the 1900s, palm oil has been increasingly added into food by the global commercial food industry because it remains stable in deep frying, or in baking at very high temperatures, and for its high levels of natural antioxidants, though the refined palm oil used in industrial food has lost most of its carotenoid content (and its orange-red color).

The following oils are suitable for high-temperature frying due to their high smoke point:

Less aggressive frying temperatures are frequently used. A quality frying oil has a bland flavor, at least 200 °C (392 °F) smoke and 315 °C (599 °F) flash points, with maximums of 0.1% free fatty acids and 3% linolenic acid. Those oils with higher linolenic fractions are avoided due to polymerization or gumming marked by increases in viscosity with age. Olive oil resists thermal degradation and has been used as a frying oil for thousands of years.