In today’s article we will know more in depth the characteristics of the most important vegetable oils, as well as the aspects that we must take into account when choosing one or the other to cook.
Choose the cooking oil correctly
Vegetable oils are obtained from seeds, legumes, nuts and some fruits. Basically, vegetable oils are fats that are in the liquid state at room temperature. All fats are made up of triglycerides, which in turn are made up of fatty acids linked to glycerol. Vegetable oils contain a mixture of saturated fatty acids (major in animal fats) and monounsaturated and polyunsaturated fatty acids which, with few exceptions, predominate in the composition of vegetable oils.
Vegetable oils may have different levels of refining. The refining of oils is used to remove any unwanted taste, odor, color or any type of impurity that may appear during the manufacturing process. In short, at lower refining, greater purity of the oil and, consequently, higher organoleptic and nutritional quality.
During cooking, oils not only serve as heat transfer medium but are also absorbed by food and therefore, a part of the cooking oil we consume when taking these foods.
The oils, as a consequence, should be treated with great care. Fatty acids are sensitive to heat; light and oxygen, and overexposure to these factors during storage or cooking can change the chemical structure of fatty acids.
The stability of the fatty acids that make up the fats of vegetable origin vary between the different oils and these are indicated by measuring the “smoke point”, i.e. the temperature at which the decomposition of the fats becomes visible with a bluish smoke . If the cooking temperature is too high, the oil degrades over time. Generally, the more times it is heated, the more it will deteriorate. On the other hand, using a lower temperature, the cooking time is extended and the amount absorbed by the food will be higher.
It is also important to note that the higher the level of unsaturation of the fatty acids, the lower the heat stability of the same. Oils rich in monounsaturated fatty acids such as virgin olive oil, peanut oil, rapeseed oil or high oleic sunflower oil will be more stable than corn oil or normal sunflower oil.
Repeated use of oil, typical of frying, reduces the temperature at which the “smoke point” occurs, although this effect will occurs later on stable oils, such as high oilseed rape and high oleic sunflower oil as we have seen. If we use oil solely for frying, we will filter it after frying (cold) to remove the remains of particles. The bucket where we keep the frying oil should be clean and dry.
In practice, oils can be used several times as long as the sensory characteristics of the oils are kept intact. In general, it is advisable to completely renew the oil after 10 uses.