Learning about extra virgin olive oil > Preservation and uses of oil

“New oil, old wine”; popular wisdom clearly points out that the quality of oil declines with age and it is a good rule to use it within the year of its production. Generally it is thought that the product should be consumed preferably by a certain date, generally 24 months from the date of bottling. Is this rule always valid?

Normally, a correctly preserved oil, sealed in its bottle, arrives at its second birthday without problems; it contains antioxidant components by nature which protect it from rancidifying, even though their action becomes weaker as time goes on.

The presence of these antioxidant substances (phenolic compounds and tocopherols amongst them) may be nullified if certain rules for the preservation of oil are not observed at home.

First of all, the oil must be protected from direct light and heat and the bottle, once opened, should be kept tightly closed: three simple but indispensable rules for protecting antioxidant substances which are extremely easily destroyed.

Once the oil has been exposed to air, it should be consumed in a reasonably short time, and the top should be tightly closed each time. Metal pourers should not be left on the bottle as they do not allow for a perfect seal.

Contrary to what one might think, cold does not cause any alterations in the structure of the product and its preservability. Confusion also arises regarding taste from the diffusion of  an insufficiently clear technical terminology: since acidity is often cited as a parameter on which to base the quality of an extra virgin – and this is really a fundamental aspect – it is easy to think that this acidity can be tasted in the oil, whereas it is definable only through a laboratory analysis. So, if an extra virgin oil of recent pressing on tasting has a very intense taste of the fruit, which causes a slight nippiness in the throat – the sensation of fruitiness which experts find delicious – this is easily confused with an excess of acidity.

The recognition of the better nutritional qualities of olive oil compared to animal fats has given rise to the mistaken idea that every fat of vegetable origin is good or is more healthy, with the result that some people use margarine instead of butter in the serious belief that they are protecting their health.

Margarine is produced from hydrogenated vegetable oils, that is turning the double links of fatty acids into saturated fats by means of the absorption of hydrogen. Thus the benefit that vegetable oils have in the prevention of cardiovascular diseases, linked above all to the presence of mono- and polyunsaturated fatty acids, is completely nullified.

Another very common mistake is that the best way to behave, to prevent an increase in cholesterol levels and in general to enjoy good health, is to adopt a diet as poor in fats as possible. A diet with a low quantity of fats tends however to lower both good and bad cholesterol, with obvious ill effects on bodily functions.

A diet which is rich in olive oil helps to keep one’s LDL levels down (“bad cholesterol”) while it does not lower HDL (“good cholesterol”, known as the street sweeper of the arteries), which is protected by monounsaturated fatty acids in which olive oil is rich.

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