Olive Oil vs Vegetable Oils

All fatty substances are altered and oxidized under the effect of temperature proportionally to the thermal stress. However, the chemical composition of oils causes a different response.

Olive oil has a high ratio of mono-unsaturated to poly-unsaturated fat and at the same time a plethora of anti-oxidant substances which make it stable. On the other hand, vegetable oils, deficient in anti-oxidants, become highly unstable.

Due to this substantial difference, oils respond to thermal stresses in a different way. To sum up, the following differences may be referenced:

1) fatty substances are characterised by two critical temperatures. The first one concerns the temperature when smoke appears and the second one the temperature of alteration. Olive oil has the enormous advantage of having smoke point much smaller than the temperature of alteration. So, when the olive oil begins to give off smoke, we lower the intensity of the heat in order to keep the temperature stable. Therefore, the olive oil is not spoilt. For vegetable oils this relation is inverse. Specifically:

Fatty substance Smoke point Temperature of alteration

Virgin olive oil 200 ºC 230 ºC

Corn oil 227 ºC 160 ºC

Soybean oil 256 ºC 170 ºC

The temperature of alteration for olive oil is significantly higher than other vegetable oils. What is more it is higher than the normal cooking - frying temperature which ranges from 160 ºC to 200 ºC.

2) Olive oil, even after the beginning of alteration, it oxidizes less than vegetable oils as it creates fewer peroxides and free radicals that have serious negative effects on our health.

3) Olive oil can be reused safely up to 3-4 times in the pan if:
a) The temperature does not exceed 180 º C
b) It is filtered after each use and
c) It is kept in a dark and cool place.
For the same conditions, vegetable oils are better not to be re-used as they produce many trans substances, even from the first frying.

4) By using the shallow frying method (partially covered food) and under control conditions-temperature less than 180 ºc and brief frying time- beneficial effects have been observed on foods as they were enriched with valuable ingredients of olive oil. Specifically, alpha-tocopherol, terpenic acids and polyphenols have been detected in a degree that varies according to the fried food.

5) Consumption of food fried in olive oils, increases blood triglycerides considerably less, compared to other vegetable oils.

6) Consumption of fried oils increases the coagulability of blood but the effect of olive oil is smaller than of seed oils.

7) When food is fried in olive oil, a "thin and crispy crust" is created that protects it from the "deep" impregnation. Thus, less olive oil is consumed during frying while the food is not burdened with many calories (unless the frying time is long so the ' crust ' breaks and no longer performs its protective role).

8) Food cooked with olive oil is more digestible as olive oil:
a) is absorbed by the human body to a degree of assimilation that approaches 98% and
b) increases the content of gastric juice in "pepsin" facilitating digestion and absorption of nutrients from food.

9) Olive oil darkens after one or two uses. This is explained by the "firing" of natural pigments (carotenes – chlorophyll) which is not a defect but proof of its naturalness

10) According to the indications of chefs and tasters, dishes cooked with olive oil excel in palatability and flavour.

Meanwhile, apart from all the differences that have been noted, there is one important similarity to be mentioned:

Olive oil and seed or vegetable oils give exactly the same number of calories i.e. 9kcal/g. Thus, claiming that seed oils are lighter than olive oil, is just a fable.

Of all the above, the conclusions to be drawn are yours.

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