Research has shown that extra virgin olive oil (EVOO), is a healthier option than other vegetable oils.
Extra Virgin Olive Oil (EVOO), is a high-quality source of bioavailable phenolic substances that offer a variety health benefits for many diseases, such as:
Neurodegenerative Disorders and Other
Olive Oil is monounsaturated and higher in bioactive chemicals than other vegetable oils. It is well-known that olive oil can be made into a healthy, all-purpose oil. However, it is not easy to maintain the many nutritional properties below. Let's look at the research surrounding Olive Oil and different national approaches, including deep frying, pan frying and boiling.
The latest research was published in Food Chemistry (2015). It examined the effects of a combination national cooking methods within the article of different Mediterranean foods: tomato, eggplant, pumpkin, and potato. All four different cooking methods were analyzed.
Deep-frying at 180°C
Boiling (plain water)
Boiling (waterEVOO mix - both boiling at 100degC).
Each participant was given a ten-minute intake. Then, five minutes of heating were followed by testing and refrigeration.
Surprisingly, the analysis showed that vegetables with extra virgin olive oil (EVOO), were significantly better because they are made with phenols from the oil.
Although it may seem like this, it is important to note that the fat content in boiling is much higher than what is expected.
It is important to remember that the effects for each vegetable did not vary. Because the compounds were found to be more concentrated at deep-fried vegetables, the conclusion was that each of the cooked vegetables had its own phenolic or antioxidant activity profiles. This was due to the characteristics of the raw vegetables as well as the ingestion strategies.
A second study was published in Food Chemistry Toxicology (2010) and focused on the effects of olive oil frying. The analysis involved five samples of commercial Olive Oil, including one Extra Virgin Olive Oil (EVOO) from northeast Portugal. As the vegetable subject, potatoes were used along with domestic deep-fat electric fryers at 100 degrees Celsius. Before frying, all Olive Oil contained similar total phenolic compounds (TPC).
It was found that "the degradation rates were similar to amongst all oil samples with a 0.7 percent rise an hour at Extra Virgin Olive Oil, and 0.8 percent in every other olive sample, with no obvious differences." The highest oxidative stability was achieved by Extra Virgin Olive Oil. After six hours of frying, only the Extra Virgin Olive Oil, (EVOO), still contained phenols. The other oils have been reduced.
It is not common to cook for 6-12 hours in domestic circumstances so the analysis concluded that olive oil, separate from the commercial category, is "clearly resistant" to degradation under national cooking conditions (one billion degrees Celsius).
Another study was published in the Journal of Agriculture and Food Chemistry 2003. It involved potato bits that were exposed to deep frying at a temperature of 115°C and Extra Virgin Olive Oil (EVOO) for 10 minutes. The analysis showed that the concentrations of phenolic chemicals decreased by 40-50% after one frying process, compared to their original concentration. After six frying sessions, less than 10% of the original concentrations were left.
The total antioxidant power decreased from 740 l Trolox/kg to less than 250 seconds after the initial frying session, and further to 139-144 Umol/kg after 12 frying sessions. Extra Virgin Olive Oil (EVOO), showed remarkable resistance to the formation and total polar materials.
The pan frying process causes a slightly faster degradation of Extra Virgin Olive Oils (EVOO) than deep frying. A review published in Food Research International (2013) suggests that this could be due to "higher foodoil contact surfaces, higher vulnerability and lower temperatures." They also mention that fried foods are enhanced with olive oil antioxidants in comparison to other vegetable oils as long as they are not heated too much.
In a report published in Food Science and Technology (2010), a sample of Extra Virgin Olive Oil and Olive Oil was used together with carrots and onions to assess the effects of peanuts. The vegetables were boiled for 60 seconds, with 60 grams of each Olive Oil at the beginning or 15 minutes before the end of the boil.
The results showed that boiling does NOT cause oxidation, as expected. Concentrations of all polyphenolic and tocopherol elements, as well as tocopherols, decreased. However, just 15 minutes before the boil was over, Olive Oil was added to the boiling water. This increased the "content of oleanolic acids derivatives, 3,4 DHPEA–EA and 4- HPEA–EA, as well as hydroxytyrosol acetate."
The behavior of olive oil's phenolic compounds during roasting was the subject of a report published in Food Chemistry (2010). The analysis revealed that the samples included extra-virgin oil (EVOO), virgin oil (VOO), oil of olive (OR), oil of sunflower (SFO), oil of soy (SO), oil oil from corn (CO), and oil made with peanut oil.
150 grams of beef (in a block form) or 150 grams of potatoes (six quarters). Now, the vegetables were processed at 60 grams of each oil in an oven at180 degC. The inner temperature of the meat reached 100 before it was cooked. This took on average forty-five seconds.
Sunflower and seed oils were more prone to oxidization and did not retain their antioxidant properties. Olive oil was the exception, and it didn't oxidize during roasting. The authors attribute this to higher levels of tocopherol. The oil samples, such as olive oil, had higher levels of phenolic compounds. These amounts were significantly decreased after roasting. OO samples showed a dramatic decrease in 3,4-DHPEA–EDA (98%) and 3,4–DHPEA–EA (70%), respectively. However, OO samples had a higher level of radical activity than other vegetable oils.
The process of Olive Oil processing can lead to Olive Oil degrading. This is an intricate issue that involves many factors. Despite the benefits of heavy fryingpans, high temperatures from deep frying can cause chemical changes like oxidation and polymerization.
Olive Oil, however, is superior to vegetable oils in terms of its resistance to oxidation and free radicals.
The study, published in Food Chemistry 2015, states that chemical reactions can be influenced by oil quality, food properties and food/oil ratios, among other factors.
Olive Oil, and especially Extra Virgin Olive Oil, is considered a healthy cooking oil, particularly when compared to other vegetable oils. Cooking time can be reduced and oils not re-used may help to reduce oxidation or loss of phenolic compounds.
Olive Oil's bioactive compounds and benefits can be preserved if it is consumed raw.