How to check the quality of a vegetable oil?

Vegetable oils are mainly composed of fatty acids and it is these different molecules that give the oils their cosmetic, nutritional and therapeutic properties. But be careful, fatty acids often mean oxidation! And it is this oxidation that will affect the quality of your oil, apart from the choice of raw material at the beginning obviously. So how to choose good quality vegetable oils and especially how to store them well? We explain everything here.

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How to recognize a quality vegetable oil?

Mentions and certifications

Just like essential oils, there are many different qualities of vegetable oils. In order to guarantee the quality of your vegetable oil, it is enough to pay attention to these few points:

  • Virgin Oil: this means that the oil has not undergone any treatment before or after pressing, it is a pure oil that has simply been filtered to remove any impurities.
  • First Cold Pressed: First cold pressing is a simple, mechanical extraction method where oil-bearing fruits and seeds are pressed to extract the oil directly. It is possible to press by heating the raw material and pressing repeatedly to obtain more oil, but the quality will be lower.
  • Organic certifications: these certifications guarantee that the plant at the origin of the oil has been produced according to the principles of Organic Agriculture, and that there are no phytosanitary products in it. According to the mode of use of the vegetable oil, food or cosmetic, we will find two types of certifications: AB and Cosmos.

Quality control

These different mentions ensure that the oil has been produced in the best possible conditions, nevertheless like essential oils, vegetable oils are natural products and their final quality depends initially on the raw materials selected.

In effect, if the raw material is of poor quality, the finished product will be too, regardless of the skills of the processor. And to make sure that an oil contains all the molecules we are looking for, there is only one solution: the chromatographic analysis! It alone allows you to know precisely which molecules are present in the oil and in what proportion.

This is why the composition of the oils is meticulously analyzed to ensure the best possible quality. A small subtlety foroily macerates, it is important to check both the organic origin of the carrier oil, often sunflower oil, as well as the origin of the plant used in the maceration.

Good to know

It is possible to see tocopherol mentioned in the list of ingredients on the label of some vegetable oils. This is actually the other name for vitamin E, which is an antioxidant. It is often added to vegetable oils or oily macerates that are more sensitive to oxidation, to increase their stability and thus preserve them longer.

What should the label of a vegetable oil contain?

On the label of a quality vegetable oil, you must find :

  • The botanical name in French and Latin provides more information about the type of plant used to produce the vegetable oil.
  • The method of obtaining with the mentions virgin oil of first cold pressure
  • The certifications with the COSMOS ORGANIC logo certified by Ecocert or the AB and Eurofoil logos certified by Ecocert FR-BIO-01.
  • The list ofingredients ideally with the chemical composition and part of the plant used.
  • TheLot number, thegeographic originand thecoordinates of the manufacturer are a guarantee of traceability

How to store vegetable oils?

If essential oils are stable products that can be kept for several years at room temperature, vegetable oils are less stable and will age more quickly, particularly because of their fatty acid composition.

The oxidation of vegetable oils

Vegetable oils are often defined by their oxidative potential, this is a degradation of the fatty acids that make up the oil and which will therefore alter the quality of the oil. This oxidation can be caused by various factors:

  • Oxygen from the air: an oil in contact with the air can in the long term alter the molecular structure of the fatty acids and thus modify the structure of the oil. This phenomenon of alteration of the oil, is explained by the fixation of oxygen atoms on the carboxylic acid functions of the fatty acid.
  • Light: UV rays are factors in the degradation of the links between the atoms forming the fatty acids. Thus, too frequent exposure to light can lead to the formation of free radicals and mutations that alter the quality of the oil.
  • Container interactions: metal packaging, such as iron or copper, can react with the contents and release molecules that will degrade the oil.
  • Heat: it is known that heat acts as a catalyst in these reactions, that is to say that it will promote the denaturation of fatty acids and therefore lead to the oxidation of the oil. Even if some oils are less sensitive to heat than others, it is important to keep them in a cool place.

These factors can therefore promote the oxidation of oils and consequently lead to allergic reactions, pimples (because an oxidized oil becomes very comedogenic) and a rancid odor when used. It is therefore important to store your oils away from heat and light, but also in a cool, dry place to avoid any contamination of microorganisms and in a suitable container! A virgin oil extracted by first cold pressing is richer and will therefore tend to degrade more quickly than mineral oils. This is why it is essential to take care of the conservation of your vegetable oils.

Here are some examples of vegetable oils classified according to their stability to oxidation:

  • Excellent:Oil of