Fats bring significant benefits to the body. They are part of the cell membrane, they take part in the absorption of fat-soluble vitamins (A, D, E, K), they ensure the proper functioning of the cardiovascular system and the nervous system. However, excessive consumption leads to atherosclerosis and heart disease, overweight and diseases of the digestive system. In this article, we suggest on which fat you can fry.
Taking into account the chemical processes, the selection of fat for frying should be made due to its characteristics. It is worth emphasizing that fat is an essential component of our daily diet. Its amount in the diet should fluctuate within 20-30% of the total energy demand. First of all, each fat has a specific smoking temperature. This is the temperature at which many fats occur in fats, e.g. oxidation, leading to their degradation. The intensity of these changes depends on the temperature reached, the frying time, as well as the type and quality of the fat being subjected to heat treatment. During this process, peroxides, aldehydes and ketones are formed, which are very harmful to health. The frying process can adversely affect the digestive system due to the fact that frying reduces the digestibility and absorption of fats. In addition, fat oxidation products that arise when subjected to high temperature, can have a mutagenic and carcinogenic effect on our body. Oil resistance to heat treatment is determined by the ratio of saturated, monounsaturated and polyunsaturated fatty acids. The higher the percentage of saturated fatty acids, the more resistant the product to temperature. Saturated fatty acids are all fats of animal origin.
In the case of vegetable oils is much more difficult. They are more susceptible to oxidation processes, in particular products rich in polyunsaturated fatty acids. Refined and unrefined vegetable oils can be found. Refining is an additional purification. During this process, excess moisture and other substances are removed from the product, which increases the temperature of the smoke. This means that refined vegetable oil is more suitable for frying, and unrefined should be used in raw form or for frying at very low heat and for a short time.
Butter is a well-known product derived exclusively from cow’s milk. Butter belongs to the group of high-fat products, and as a zoonotic product it provides us mainly with saturated fatty acids. It is rich in vitamins A, D and E and in macro- and micronutrients, and also contains phospholipids. It also contains cholesterol. Frying butter is not recommended. First of all, because the substances contained in it during the thermal treatment break down very quickly. In addition, excessive amounts of butter added to the dishes adversely affect the metabolism of lipids, which is harmful to the heart and blood vessels. The exception is fast frying of omelette or scrambled eggs.
Sunflower oil is not suitable for frying due to the low smoke point (unrefined 100 ° C). It consists mainly of polyunsaturated fatty acids, among which we distinguish linoleic acid, which is much more susceptible to fat oxidation processes than monounsaturated oleic acid. Sunflower oil in its composition contains about 55-66% linoleic acid.
Olive oil in 99% of its mass consists of lipids. It has a high content (68%) of oleic acid belonging to monounsaturated fatty acids. For comparison – it is about 57% in rapeseed oil. These acids play a special role in the prevention of cardiovascular diseases. They inhibit the development of atherosclerotic lesions and reduce cholesterol in the blood serum. The remaining part of the lipids in the oil composition are saturated fatty acids (palmitic and stearic acid) – about 17%, and linoleic acid, which is about 8% of the lipid mass of olive oil. Due to the fatty composition and content of antioxidants, olive oil is characterized by high resistance to fat oxidation, which is why it is suitable for frying. The relative lower oxidative stability is characterized by refined olive oil. This is due to the fact that the refining process leads to a reduction in the content of antioxidants (carotenoids, tocopherols, sterols, phospholipids) in the product.
Each olive oil in 70-80% consists of monounsaturated fatty acids, namely oleic and linoleic acids. Unfortunately, these acids lose their properties at temperatures above 90-120 ° C. Considering that the frying temperature in the pan reaches 190-250 ° C, olive oil loses its valuable properties when frying. Only olive oil from a second pressing or refined olive oil can be used for frying.
Corn oil is rich in vitamins, microelements and fatty acids. Like sunflower oil in its composition contains mainly linoleic acids, therefore it is not suitable for frying. We can use it mainly in raw form or for frying in refined form. In addition, this oil can not be stored for a long time, especially in a very sunny place, because it quickly undergoes oxidation and rancidity.
Linseed oil is obtained from flax seeds. It consists mainly of linolenic acid (4.39-45%), to a lesser extent linoleic acid (16.5-17.9%) and oleic acid (26-27%). Due to the high content of polyunsaturated acids, this oil is not suitable for any heat treatment. To show its numerous pro-health properties on the cardiovascular system, it should be cold pressed. Due to the high content of unsaturated fatty acids, it can not be stored for a long time. Linseed oil should be stored in a dark package in a cool and shady place.
First of all, one should distinguish natural palm oil, which is hard even at room temperature, from its commercial version, oxidized by means of high temperatures and hydrogen to a liquid state. The second version is harmful to the body.
Natural palm oil is suitable for frying because it withstands 200 ° C. Additionally, it contains a large amount of antioxidants, tokochromanols and carotenoids (which suppress singlet oxygen), and vitamins E and A. Red palm oil is considered the best, which in 44% consists of palmitic acid and 39% oleic acid. The amounts of polyunsaturated fatty acids that are most susceptible to thermal heat treatment are small.Posted on: November 20, 2019