Trans-fatty acids (TFA) are a serious reason for cardiovascular illnesses. These dangerous fat can accumulate alongside artery partitions, proscribing blood circulation and rising the danger of coronary heart assaults. Based on the World Well being Group (WHO), TFAs are liable for over 278,000 annual deaths worldwide, and it recommends that TFA consumption needs to be restricted to lower than 1% of each day power consumption. Widespread sources of TFAs embody fried (junk) meals and processed meals equivalent to margarine, ghee, biscuits, desserts, and so forth. In processed meals, TFAs are produced by the hydrogenation of vegetable oil, a chemical course of that saturates the oil with hydrogen. Whereas the formation technique of TFAs in processed meals is well-known, proof means that they may also be created at house throughout cooking.
Research point out that unsaturated fatty acids (UFAs) can endure trans-isomerization, a molecular reconfiguration that rework them into TFAs when heated at 150 °C or greater. Alternatively, sulfur-containing compounds, equivalent to isothiocyanates and polysulfides, that are discovered in lots of greens, are identified to advertise geometrical isomerization of carotenoids (e.g., lycopene in tomato) -;pure pigments that give greens their crimson, orange, or yellow coloration. This raises the query that whether or not these sulfur compounds additionally promote the trans-isomerization of UFAs in on a regular basis cooking. Understanding the impression of pure sulfur compounds on the cooking course of may help regulate TFA consumption, notably for individuals who keep away from processed meals.
To discover this, a Japanese analysis staff led by by Mr. Junji Obi of Nissui Company and Dr. Masaki Honda of Meijo College assessed the position of isothiocyanates and polysulfides in selling the trans-isomerization of vegetable UFAs throughout cooking. The analysis was printed on-line on November 27, 2024, within the journal Meals Analysis Worldwide.
The researchers first evaluated the consequences of sulfur compounds in triacylglycerols (TAGs) in a mannequin system utilizing reagents. Then, exams had been carried out utilizing components (garlic, onion, leek, cabbage, horseradish, and broccoli sprouts) and vegetable oils (soybean and olive oils) to simulate precise cooking processes.
“We needed to know the principal traits of UFA isomerization in TAGs promoted by sulfur compounds by a mannequin system utilizing reagent-grade sulfur compounds and triglycerides,” explains Junji Obi, the primary writer of this paper. “We had been within the results of temperature, response time, sulfur compound focus, the kind of sulfur compounds, and addition of antioxidants on UFA isomerization.”
The staff additionally assessed the position of antioxidants equivalent to α-tocopherol in lowering the isomerization of UFAs in triglycerides like triolein and trilinolein.
The examine revealed that sulfur compounds considerably promote heat-induced trans-isomerization of UFAs in vegetable oils, particularly when cooking temperatures is above 140°C. The addition of antioxidants considerably decreased the promotion of UFAs isomerization by isothiocyanates, whereas they did little to inhibit the promotion of isomerization by polysulfides. This explains that cooking polysulfide-rich greens equivalent to garlic and onions in vegetable oil at excessive temperatures can generate TFAs. The truth is, this examine demonstrated that garlic and onions considerably promote the trans-isomerization of UFAs.
Beneath regular cooking situations, the corresponding enhance within the trans isomer ratio is anticipated to be minimal, at most a number of percentages. Due to this fact, whereas extreme warning shouldn’t be mandatory, it is very important acknowledge that cooking with components wealthy in sulfur compounds could enhance the danger of TFA consumption.
“Launch of TFAs underneath regular cooking situations is anticipated to be minimal. Due to this fact, extreme warning is pointless,” concludes Dr. Honda, the corresponding writer of this paper. “Nonetheless, it is very important perceive that cooking with components wealthy in pure sulfur compounds could enhance the danger of TFA consumption.”
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Journal reference:
Obi, J., et al. (2025). Greens containing sulfur compounds promote trans-isomerization of unsaturated fatty acids in triacylglycerols in the course of the cooking course of. Meals Analysis Worldwide. doi.org/10.1016/j.foodres.2024.115425.
