A group of researchers from Spain and Brazil have found that polyphenols are exchanged between vegetables and olive oil when they are cooked together. The process makes the polyphenols more accessible to the body and easier to absorb.
The study examined the traditional methods of Mediterranean cooking to find out how extra virgin olive oil interacts with other ingredients. The researchers found that as well as polyphenols, various other bioactive compounds from the vegetables were also absorbed by olive oil when cooked.
The research focused on a popular Mediterranean cooking technique for preparing a light sauce with tomato, onion and garlic, known as the sofrito method. Sofrito reportedly contains 40 different phenolic compounds and a high carotenoid content. The consumption of sofrito is associated with reduced cardiovascular risk and insulin sensitivity.
After the cooking process, an analysis of the olive oil showed that it was infused with polyphenols from the vegetables in the sofrito sauce; specifically with naringenin, ferulic acid, quercetin and Z-isomer carotenoids, none of which are typically found in extra virgin olive oil.
The temperature at which the sauce is cooked is important. If it is too hot, the polyphenols are oxidised and become ineffective. Temperatures over 100 degrees celsius begin to have an effect on the anti-inflammatory properties of the sauce.
The migration of bioactive compounds, such as polyphenols and carotenoids, from the tomato to the olive oil explains the findings of previous research work, which also found that sofrito sauce has increased anti-inflammatory properties.
This research show that, apart from consuming the ingredients and staple foods of the Mediterranean diet, using traditional cooking methods can also play a part in providing the full benefits of this type of cuisine.
Reference
Using Extra Virgin Olive Oil to Cook Vegetables Enhances Polyphenol and Carotenoid Extractability: A Study Applying the sofrito Technique. Molecules 2019, 24(8), 1555; https://doi.org/10.3390/molecules24081555