The word of the Month:Acidity and other chemical parameters


Chemical parameter that measures the percentage of free fatty acids contained in a sample of olive oil. This parameter is measured by degrees, one percent is a degree and has no direct relation to the sensory characteristics of the sample, ie, it does not refer to acidic flavors or correspond to more or less intense tastes, as erroneously associated .
Source: Mercacei

Oleic Acid: Monounsaturated fat typical of vegetable sources and predominant in olive oil.

The acidity has nothing to do with the taste or corresponds to more or less intense tastes. It is related to the processing process. A high acidity indicates anomalies in the state of the fruits, in the treatment and / or in the conservation. It is also important to know that a very low acidity, for example 0.1 °, is not necessarily synonymous with exceptional oil.

In fact, for a little more than two years, EEC regulations banned the mention of the degree of acidity on the label of an extra virgin oil unless it was accompanied by other chemical parameters such as that of peroxides (Determines the initial oxidation Of virgin olive oil and the deterioration that may have been suffered by natural antioxidants, polyphenols and certain components of nutritional interest, such as vitamin E, tocopherols. It is a control of good practice in the production of extra virgin olive oil)

Polyphenols: Natural antioxidants present in olive oil, which prevent oxidation.

Tocopherols: A substance present in 90% extra virgin olive oil. Its main functions are Vitamin E and high antioxidant power.


To confirm the quality of an olive oil one of the most usual analytical tests is the spectrophotometric. It measures the extinction coefficient of a grease. These tests are governed by several regulations (EC) such as nº 2472/1997 or nº 1989/2003.
The K270 factor is a spectrophotometric test in the ultraviolet wavelength range that can indicate the presence in the oil of secondary oxidation compounds (other than peroxides) that exhibit a maximum absorption at the wavelength of 270 nm. These compounds are a result of the state of conservation of the oil, of changes suffered as a result of technological processes, contamination or adulteration.

The ability to fade over time is measured. An oil will be of higher quality when lower its index K270, the greater value will indicate more amount of substances that have undergone oxidation (the oil is more altered).
Source: Cook Book Laboratory


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