TFAs are harmful fats that can build up along artery walls, blocking blood flow and increasing the risk of heart attack.
Although TFAs are commonly found in processed foods, evidence suggests they may also be formed at home during cooking. Studies show that unsaturated fatty acids (UFAs), which are generally considered beneficial, can undergo trans-isomerization – a molecular reconfiguration that turns them into TFAs when heated to 150 degrees Celsius or higher. It changes.
To find out, researchers at Meijo University examined the role of isothiocyanates and polysulfides — sulfur-containing compounds found in vegetables such as garlic, leeks, onions, scallions and shallots — on vegetable UFAs during cooking. In promoting trans isomerization.
The team first examined the effects of sulfur compounds on triacylglycerols (TAGs) in a model system using the reagents. They then experimented with garlic, onion, leek, cabbage, horseradish, broccoli sprouts, and vegetable oils such as soybean and olive oil to mimic the actual cooking process.
The results, published online in the journal Food Research International, show that sulfur compounds significantly promote the heat-induced trans-isomerization of UFAs in vegetable oils. This is especially true when the cooking temperature is above 140 degrees Celsius.
In addition, the team also examined the role of antioxidants such as alpha-tocopherol in reducing the isomerisation of UFAs into triglycerides such as triolein and trilinolein.
Although the addition of antioxidants significantly reduced the promotion of isomerisation of UFA by isothiocyanates, they did little to prevent the promotion of isomerisation by polysulphides.
“This suggests that cooking polysulfide-rich vegetables such as garlic and onion in vegetable oil at high temperatures can produce TFAs. Studies show that garlic and onion significantly promote the trans-isomerization of UFAs.” ” said the team led by Dr. Masaki Honda at Mijo University.
On the other hand, the release of TFAs under normal cooking conditions is minimal.
“Cooking with ingredients rich in natural sulfur compounds may increase the risk of TFA intake,” the researchers said.
According to the World Health Organization (WHO), TFAs are responsible for more than 278,000 annual deaths worldwide. The World Health Organization recommends limiting TFA consumption to less than 1 percent of daily energy intake.