Olive oil: how to choose it

December, the month we enjoy the products of the olive, which was harvested the previous month. Chief among its products is olive oil, the main fat source of the Mediterranean Diet. The flesh of the olive contains 20-30% of oil, which is obtained by pressing and extraction. It is marketed as extra virgin olive oil, with acidity less than 0.8-1%, produced only by mechanical means, without chemical treatment, as virgin olive oil with acidity less than 2% and as olive oil that is a mixture of virgin and refined olive oil with less acidity from 1.5%. Olive oil contains 70-80% monounsaturated (oleic acid), 6-16% omega-6 fatty acids, 0.3-1.3% omega-3 fatty acids and 8-10% saturated fatty acids.

Oleic acid contributes to the increase of HDL ("good" cholesterol) while reducing the oxidation of LDL ("bad" cholesterol), thus also its atheromatogenic effect and contributes to the prevention of cardiovascular diseases. Olive oil contains 64-86% oleic acid and polyunsaturated fatty acids and is a very good source of vitamin E. Virgin olive oil contains 100-140 µg tocopherol/g.

But how should we choose olive oil?

The first thing to check is its organoleptic characteristics. It should taste and smell good. The aromas can be fruity or reminiscent of chamomile or marjoram. If there are unpleasant odors, reminiscent of mold, spoiled cheese, aged or burnt oil or dirt, then you should be wary of buying and consuming this particular olive oil. In terms of taste, we look for bitter and spicy. If it tastes bitter (like that of medicines), rancid, or leaves the feeling of oils, avoid consuming it.

Olive oil deteriorates under the influence of light and oxygen. That is why we must always choose it in opaque packaging so that it does not come into contact with light, from the lowest shelves of the supermarket and from the last rows. This is also the reason why most of us, without knowing it, store olive oil in the cupboard under the sink which is usually dark and cool. It is also good to avoid leaving it on the kitchen counter or table for a long time, especially if it is in a transparent package and comes into contact with light.

As for oxygen, in order not to alter its organoleptic characteristics and its acidity, it should be in small packages because oxygen enters the contents of the package even through the small hole it has. Especially if we source olive oil from producers in large containers, the first amount of oil that we take out of the container will be superior in taste and quality than the last one due to its mixing with oxygen during its transfer from the large container to a smaller and usable one for daily use. The best containers for storing the oil are dark glass bottles. Glass is, after all, a stable and inert material and the dark color is necessary, because the oil oxidizes if it comes into contact with light. Whenever it is good to transfer it from the beginning in opaque glass packages and use it from there to reduce its oxidation. However, we should be particularly careful with the bulk anonymous oil because it does not have an expiry date, is not subject to quality controls and no one guarantees its quality and authenticity.

Consume olive oil both raw and cooked, even in the pan and benefit from its many beneficial components.

Irene Kontopidou,

Clinical Dietitian, M.Sc.

www.adunatizw.gr