The quality criteria for the right categorization of an olive oil derive from the chemical analysis and the organoleptic evaluation (smell and taste assessment, only for virgin olive oils) which determine and ensure its quality.
The International Olive Council (IOC) and Regulation (EEC) No 2568/91 and its amendment on 11 October 2016, regarding the characteristics of olive oil, clearly determines criteria for categorizing each oil.
The table below serves as Annex 1 (page 11) in the above stated regulation:
Table 2: Annex 1 (EC) Νο1989/2003
According to Annex 1 of the regulation, olive oils are categorized into 8 different categories according to some physico-chemical parameters such as:
Acidity, which is an important parameter for the qualitative evaluation of an olive oil. It is the content of olive oil in free fatty acids created by the enzyme lipase, which is found in the fruit.
The factors that negatively affect acidity are:
Overripe or injured fruit
Fruit affected by the olive fruit fly
Prolonged storage of the fruit after harvest and until the extraction process
Number of peroxides, where peroxides are chemical compounds generated by the effect of oxygen (oxidation).
Oxidation can be enzymatic (it is created during the olive oil extraction process by enzymes present in the olives) or chemical (it is created during the storage of olive oil after the olive oil extraction).
The factors that negatively influence the number of peroxides are:
injured fruit during harvesting, storage
olive oil contact with vegetable water
light
temperature
oxygen
traces of metallic elements
Spectrophotometric UV test
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Indicator K232, demonstrates the storage conditions of an olive oil
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Indicator K270, demonstrates how fresh an olive oil is
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Indicator Delta-K, demonstrates cases of adulteration by mixing different qualities of olive oil
The factors negatively affecting ultraviolet absorption are:
air
light
temperature
traces of metallic elements
Organoleptic evaluation, according to the IOC* standards, concerns only the virgin olive oils (extra virgin and virgin) and not the other categories listed in Table 1, such as refined olive oils and olive-pomace oils, which have not been produced with mechanical methods.
The organoleptic assessment concerns the following:
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It locates and describes the characteristics (positive or negative) of an olive oil using the senses of smell and taste from a specialized tasting panel.
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It is a necessary qualitative criterion for the classification of an olive oil in the categories of extra virgin or virgin or lampante depending on its organoleptic characteristics.
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It is equivalent to the other quality parameters and irreplaceable
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It uses a group of selected, qualified testers (recognized by the IOC) to classify virgin olive oils according to the perceived intensity of the predominant defect and the presence or not of fruity.
