Vegetable oils under the microscope

All these are essentials for cooking, yet do you know the oil you use? Using vegetable oil for cooking is a standard practice today, however, not everyone can withstand high temperatures.

Vegetable oils under the microscope
New oil and old vegetable oils. Photo: Gabriele Cantini via Flickr

They are essential for cooking, but do you know the oil you use? Using vegetable oil for cooking is a common practice today, however, not everyone can withstand high temperatures, and where the "smoke point" takes importance. The term "smoke point" refers to the temperature at which the oil begins to smoke and decompose. Oils with high smoke points are good for frying and stir-frying over high heat: Peanut oil, Sesame oil, and Soybean oil. Oils with a moderate smoke point are good for frying over medium heat: Avocado oil, Corn oil, Canola oil, and Olive oil.

Effect of temperature on oils

Above a certain temperature, fatty acids begin to alter, generating free radicals and harmful compounds and triggering negative aspects for the organism.

Above a certain temperature, carcinogenic substances are generated, and heat destroys vitamin E, a natural antioxidant in fats.

The fact that the vegetable oil is beneficial or not, depends on the type of fatty acids that it contains, and these are divided in

Saturated fats such as butter, sausages, cheeses, whole milk, and pork, chicken, and beef

Polyunsaturated fats such as fish, nuts, seeds, and dried fruits, foods containing Omega 6 and Omega 3.

Monounsaturated fats such as avocado and olives

Oils provide essential fatty acids such as linoleic and linolenic acids and fat-soluble vitamins (A, D, E, and K).

An oil of vegetable origin should not suffer transformations and when hydrogenated it loses many of its natural benefits, even causing the development of cancer cells.

In turn, fatty acids contain two types of omegas:

Omega 6: Reduces risks of heart disease, bad cholesterol levels, increases good cholesterol, and decreases the risk of cancer.

Omega 3: Benefits heart rate, vasodilation, blood clotting, immune system, central nervous system, and hormone regulation.


The oil obtained from this native South American plant is a colorless or yellowish liquid with a faint nutty odor and a mild flavor.


The oil is obtained from pressing or cooking, the fruits are roasted and passed between cylinders and the preparation is made in a hydraulic press. The ground seeds are mixed with hot water and boiled to allow them to float and be collected. When extracting the oil, salt is usually added to make the proteins coagulate and help the oil to separate.

Benefits of peanuts

It improves blood circulation and oxygenation.

Increases cellular metabolism.

Reduces cholesterol oxidation.

Decreases the synthesis of bad cholesterol.

Increases the formation of good cholesterol.

It highlights its content of vitamin E.

It resists heat very well, so it is suitable for frying.


The oil is obtained from the ground seeds of the canola plant, which is native to the Mediterranean and Asia. These contain about 44% oil. The oil that is extracted is yellow, It stands out for having a minor content of saturated fatty acids and a high content of monounsaturated acids, the reason why its consumption is highly advisable.

Benefits of canola

It is low in saturated fat 7% of total fatty acids lower than any other oil.

It is a source of Omega 6 fat, 19% of total fatty acids.

It is high in Omega 3 vegetable fat, 9% of total fatty acids, the highest content in any common oil.

Rich in monounsaturated fat.

Source of vitamins E and K.

Prevents coronary and vascular diseases such as thrombosis and arteriosclerosis.

It helps prevent diseases such as cholesterol and triglycerides in the blood.


Safflower oil is extracted from the seeds of the plant of the same name and is native to India. In the chemical extraction process, this oil is refined through heat and the addition of other chemicals, which reduces its natural nutritional benefits.

Benefits of safflower

It contains a high percentage of Omega 6 which protects against coronary diseases or arteriosclerosis.

It is rich in vitamin E, ideal for moisturizing dry skin.

It is recommended to prevent and improve cardiovascular diseases, arthritis, rheumatism, constipation, and intestinal parasites. It also revitalizes dry hair and controls dermatitis.


Sunflower oil is of vegetable origin and is extracted from the pressing of seeds of the plant. It has a crystalline appearance and a pale yellow color.

Benefits of sunflower seed

It is mainly made up of polyunsaturated acids, the most important of which are Omega 3 and Omega 6, which are considered essential and must be provided daily.

Rich in vitamin E.

It has anti-inflammatory properties, so it is suitable in cases of arthritis, premenstrual syndrome, and inflammatory diseases.


Corn oil has a pale, crystalline appearance, is not very aromatic, and has low acidity. It is ideal for frying due to its high smoking point, excellent for baking, and can be used as a dressing. It is obtained from humidified corn starch, it is ground and dried, finally, the raw oil is refined.

Benefits of corn

It bears high temperatures well, however, virgin oil does not bear high temperatures, so it is used as a dressing for its more intense flavor.

It prevents the formation of cholesterol plaques in the arteries.

It has antioxidant and anti-aging properties due to the large amount of vitamin E.


The grape is native to the Caucasus and Western Asia and as its name suggests, the oil is extracted from the grape seeds. The oil is obtained by grinding the seeds that are released from the grapes used for wine production. It is very aromatic and has an accentuated grape and nutty flavor. It has a delicate pale color. It can be used cold to dress salads or in the maceration of meats. Its boiling point is high, which allows it to resist heat well.

Benefits of the grape

Its high linoleic acid content stands out.

It provides large amounts of vitamins C and D, but if the greater concentration is in unsaturated fatty acids, such as Omega 6.

Due to its content of essential fatty acids, it is a great help in controlling cholesterol, since it increases the good one and reduces the bad one.

It regulates triglycerides and helps prevent hypertension and diabetes.

Due to its richness in Omega 6, it is excellent for people with circulatory problems, preventing heart attacks.

It has anti-inflammatory properties, which help people with rheumatic diseases.


The soybean is a legume that contains from one to four seeds in its pod and is native to Southeast Asia. Soya oil is obtained from yellow seeds collected at full maturity through the process of breaking, flaking, and extraction. It undergoes a refining process. It is unctuous, light, and yellowish. It tends to go stale fairly quickly. It has an intense and particular flavour.

Benefits of soya

It is abundant in Omega 3 Omega 6.

It helps to keep the central nervous system in good condition.

It is rich in mono- and polyunsaturated fats.

It is a source of vitamin E and helps the correct absorption of liposoluble vitamins such as A, K, and D.

When fried it is absorbed less in food, so it yields more than other oils.


The olive tree is a fruit that originated in Mesopotamia (now Iraq) from where it spread to the Mediterranean. The olives are harvested as they reach maturity, not before, and damage to the fruit should be avoided and not mixed with broken olives. Harvesting methods can be:

Milking: The olives are picked by hand, one by one.

Shaking: The trunk or branches are shaken to remove the fruit. This method can damage them.

Shaking: This is the traditional method. It consists of gently beating the branches of the tree with a stick so that the ripe fruit falls into a net.

Benefits of the olive

It helps lower cholesterol and reduces levels of bad cholesterol.

The antioxidant components of extra virgin olive oil slow down the formation of atheroma plaque which leads to the obstruction of arteries.

It is a source of vitamins E and K.

It helps to lower blood sugar levels in people with diabetes.


The avocado is a fruit of the laurel family and its name is derived from the Nahuatl aoacatl or ahuacatl. The extraction method is cold-pressed and extra virgin avocado oil is extracted. The process begins with cold-pressing, a mill that chops the fruit, then it is sent to a malaxator, and finally a series of centrifuges to extract the raw oil. In the end, the oil goes through a greenhouse process to remove all the waxes so that it maintains its brilliance at low temperatures, resulting in refined top-quality oil.

Benefits of avocado

It's rich in oleic acid.

It helps reduce cholesterol, hypertension and improves heart health.

It is high in lutein. A beneficial antioxidant for the eyes, it reduces the risk of eye diseases such as cataracts or macular degeneration.

Reduces symptoms of arthritis

It neutralizes free radicals that can lead to the development of type 2 diabetes.


It is a very economical fat of vegetable origin, obtained by pressing the fruit of the palm. It is widely used in processed foods such as ice cream, sauces, kinds of margarine, cookies, bread, fried foods, or chocolates. It is best to dispense with foods that contain them. Some distributors avoid mentioning it on the label by using names such as palm kernel oil, vegetable fat, fractionated and hydrogenated palm kernel fat, or palm butter.

Its high content of saturated fat does not make it advisable for health. The World Health Organization (WHO) recommends limiting its intake because there is evidence that it can cause vascular and heart problems. In addition, its consumption damages the environment; its intensive cultivation in countries such as Indonesia and Malaysia have destroyed large tropical forests.