For decades, the word in the kitchen has been that olive oil shouldn’t be used for frying as it has a low smoke point and produces toxic compounds. But in a recent scientific trial, researchers found that extra virgin olive oil is better for frying food than other vegetable oils.
Home cooks generally opt for refined seed oils, such as canola, or, more recently, coconut oil, because of their high smoke point. However, growing evidence suggests there’s more to frying oil than the smoke point, and olive oil has been unfairly maligned.
In 2018, Australian researchers published findings from a review of 10 commonly used cooking oils: high-quality extra virgin olive oil, virgin olive oil, olive oil, canola oil, rice bran oil, grapeseed oil, coconut oil, high-oleic peanut oil, sunflower oil and avocado oil.
The oils were subjected to two trials, one to simulate pan frying and a second to simulate deep-frying. They then assessed the oils’ free fatty acids, smoke point, oil stability index and presence of polar compounds.
When oil is heated at high temperatures, or for extended periods, it degrades, forming undesirable polar compounds such as aldehydes, alkyl benzenes and aromatic hydrocarbons. Some, but not all, of these compounds have been linked to cancers and neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease.
The link between these compounds and health is dependent on the level of exposure, and many countries limit the amount of total polar materials (TPM) allowed in frying oil. Typically, less than 24-27% is considered safe for food eaten immediately after frying. For fried food that is packaged or stored, the oil must have less than 10% TPM to ensure that it doesn’t exceed the 24% endpoint.
The Australian study found that refined seed oils create the most polar compounds, despite their higher smoke point. And, overall, the researchers noted that extra virgin olive oil was the most stable when heated, followed by coconut oil and other virgin oils such as those made from avocado and high-oleic seeds such as peanuts.
Hence, Researchers have concluded that high-quality extra virgin olive oils are the best option for frying at home compared to other lesser-quality vegetable oils.
